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<!-- DFIN ActiveDisclosure(SM) XBRL Linkbase Document - http://www.dfinsolutions.com/ -->
<!-- Creation Date      : 2020-08-04T23:30:49.5275570+00:00 -->
<!-- Version            : 5.0.1.476 -->
<!-- Package ID         : e5aafa244b47497d9a95ff7652389aac -->
<!-- Copyright (c) 2020 Donnelley Financial Solutions, Inc. All Rights Reserved. -->
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    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityCentralIndexKey" xlink:type="locator" xlink:label="dei_EntityCentralIndexKey" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityCentralIndexKey_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Central Index Key</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityCentralIndexKey" xlink:to="dei_EntityCentralIndexKey_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeasesRightOfUseAssets" xlink:type="locator" xlink:label="psn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeasesRightOfUseAssets" />
    <link:label xml:lang="en-US" xlink:label="psn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeasesRightOfUseAssets_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Business combination recognized identifiable assets acquired and liabilities assumed operating leases right of use assets.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeasesRightOfUseAssets" xlink:to="psn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeasesRightOfUseAssets_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccruedExpensesAndOtherLiabilities" xlink:type="locator" xlink:label="psn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccruedExpensesAndOtherLiabilities" />
    <link:label xml:lang="en-US" xlink:label="psn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccruedExpensesAndOtherLiabilities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Business combination recognized identifiable assets acquired and liabilities assumed current liabilities accrued expenses and other liabilities.</link:label>
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    <link:loc xlink:href="psn-20200630.xsd#psn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeasesShortTermLeaseLiabilities" xlink:type="locator" xlink:label="psn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeasesShortTermLeaseLiabilities" />
    <link:label xml:lang="en-US" xlink:label="psn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeasesShortTermLeaseLiabilities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Business combination recognized identifiable assets acquired and liabilities assumed operating leases short-term lease liabilities.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeasesShortTermLeaseLiabilities" xlink:to="psn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeasesShortTermLeaseLiabilities_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIncomeTaxPayable" xlink:type="locator" xlink:label="psn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIncomeTaxPayable" />
    <link:label xml:lang="en-US" xlink:label="psn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIncomeTaxPayable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Business combination recognized identifiable assets acquired and liabilities assumed income tax payable.</link:label>
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    <link:loc xlink:href="psn-20200630.xsd#psn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeasesLongTermLeaseLiabilities" xlink:type="locator" xlink:label="psn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeasesLongTermLeaseLiabilities" />
    <link:label xml:lang="en-US" xlink:label="psn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeasesLongTermLeaseLiabilities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Business combination recognized identifiable assets acquired and liabilities assumed operating leases long-term lease liabilities.</link:label>
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    <link:loc xlink:href="psn-20200630.xsd#psn_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour" xlink:type="locator" xlink:label="psn_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour" />
    <link:label xml:lang="en-US" xlink:label="psn_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Lessee operating lease liability payments due after year four.</link:label>
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    <link:loc xlink:href="psn-20200630.xsd#psn_FinanceLeaseLiabilityPaymentsDueAfterYearFour" xlink:type="locator" xlink:label="psn_FinanceLeaseLiabilityPaymentsDueAfterYearFour" />
    <link:label xml:lang="en-US" xlink:label="psn_FinanceLeaseLiabilityPaymentsDueAfterYearFour_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Finance lease liability payments due after year four.</link:label>
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    <link:loc xlink:href="psn-20200630.xsd#psn_LongTermEmployeeIncentives" xlink:type="locator" xlink:label="psn_LongTermEmployeeIncentives" />
    <link:label xml:lang="en-US" xlink:label="psn_LongTermEmployeeIncentives_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Long-term employee incentives.</link:label>
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    <link:loc xlink:href="psn-20200630.xsd#psn_AdjustedEBITDAAttributableToParent" xlink:type="locator" xlink:label="psn_AdjustedEBITDAAttributableToParent" />
    <link:label xml:lang="en-US" xlink:label="psn_AdjustedEBITDAAttributableToParent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Adjusted EBITDA attributable to parent.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_AdjustedEBITDAAttributableToParent" xlink:to="psn_AdjustedEBITDAAttributableToParent_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_AdjustedEBITDAAttributableToNoncontrollingInterests" xlink:type="locator" xlink:label="psn_AdjustedEBITDAAttributableToNoncontrollingInterests" />
    <link:label xml:lang="en-US" xlink:label="psn_AdjustedEBITDAAttributableToNoncontrollingInterests_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Adjusted EBITDA attributable to noncontrolling interests.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_AdjustedEBITDAAttributableToNoncontrollingInterests" xlink:to="psn_AdjustedEBITDAAttributableToNoncontrollingInterests_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_EquityBasedCompensationIncomeExpense" xlink:type="locator" xlink:label="psn_EquityBasedCompensationIncomeExpense" />
    <link:label xml:lang="en-US" xlink:label="psn_EquityBasedCompensationIncomeExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Equity-based compensation income (expense).</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_EquityBasedCompensationIncomeExpense" xlink:to="psn_EquityBasedCompensationIncomeExpense_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_TransactionRelatedCosts" xlink:type="locator" xlink:label="psn_TransactionRelatedCosts" />
    <link:label xml:lang="en-US" xlink:label="psn_TransactionRelatedCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Transaction related costs.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_TransactionRelatedCosts" xlink:to="psn_TransactionRelatedCosts_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_RestructuringIncomeExpense" xlink:type="locator" xlink:label="psn_RestructuringIncomeExpense" />
    <link:label xml:lang="en-US" xlink:label="psn_RestructuringIncomeExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Restructuring income (expense).</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_RestructuringIncomeExpense" xlink:to="psn_RestructuringIncomeExpense_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_OtherReconciliationFromNetIncomeToAdjustedEBITDA" xlink:type="locator" xlink:label="psn_OtherReconciliationFromNetIncomeToAdjustedEBITDA" />
    <link:label xml:lang="en-US" xlink:label="psn_OtherReconciliationFromNetIncomeToAdjustedEBITDA_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Other reconciliation from net income to adjusted EBITDA.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_OtherReconciliationFromNetIncomeToAdjustedEBITDA" xlink:to="psn_OtherReconciliationFromNetIncomeToAdjustedEBITDA_lbl" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_CoverAbstract" xlink:type="locator" xlink:label="dei_CoverAbstract" />
    <link:label xml:lang="en-US" xlink:label="dei_CoverAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Cover [Abstract]</link:label>
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    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentType" xlink:type="locator" xlink:label="dei_DocumentType" />
    <link:label xml:lang="en-US" xlink:label="dei_DocumentType_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Type</link:label>
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    <link:label xml:lang="en-US" xlink:label="dei_DocumentType_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Document Type</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_AmendmentFlag" xlink:type="locator" xlink:label="dei_AmendmentFlag" />
    <link:label xml:lang="en-US" xlink:label="dei_AmendmentFlag_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Amendment Flag</link:label>
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    <link:label xml:lang="en-US" xlink:label="dei_AmendmentFlag_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Amendment Flag</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentPeriodEndDate" xlink:type="locator" xlink:label="dei_DocumentPeriodEndDate" />
    <link:label xml:lang="en-US" xlink:label="dei_DocumentPeriodEndDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Period End Date</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_DocumentPeriodEndDate" xlink:to="dei_DocumentPeriodEndDate_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_DocumentPeriodEndDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Document Period End Date</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentFiscalYearFocus" xlink:type="locator" xlink:label="dei_DocumentFiscalYearFocus" />
    <link:label xml:lang="en-US" xlink:label="dei_DocumentFiscalYearFocus_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Document Fiscal Year Focus</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_DocumentFiscalYearFocus" xlink:to="dei_DocumentFiscalYearFocus_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_DocumentFiscalYearFocus_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Document Fiscal Year Focus</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentFiscalPeriodFocus" xlink:type="locator" xlink:label="dei_DocumentFiscalPeriodFocus" />
    <link:label xml:lang="en-US" xlink:label="dei_DocumentFiscalPeriodFocus_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Fiscal Period Focus</link:label>
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    <link:label xml:lang="en-US" xlink:label="dei_DocumentFiscalPeriodFocus_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Document Fiscal Period Focus</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_TradingSymbol" xlink:type="locator" xlink:label="dei_TradingSymbol" />
    <link:label xml:lang="en-US" xlink:label="dei_TradingSymbol_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Trading Symbol</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_TradingSymbol" xlink:to="dei_TradingSymbol_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_TradingSymbol_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Trading Symbol</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityRegistrantName" xlink:type="locator" xlink:label="dei_EntityRegistrantName" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityRegistrantName_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Registrant Name</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityRegistrantName" xlink:to="dei_EntityRegistrantName_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityRegistrantName_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Registrant Name</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_EntityCentralIndexKey_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Central Index Key</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_CurrentFiscalYearEndDate" xlink:type="locator" xlink:label="dei_CurrentFiscalYearEndDate" />
    <link:label xml:lang="en-US" xlink:label="dei_CurrentFiscalYearEndDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current Fiscal Year End Date</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_CurrentFiscalYearEndDate" xlink:to="dei_CurrentFiscalYearEndDate_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_CurrentFiscalYearEndDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Current Fiscal Year End Date</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityCurrentReportingStatus" xlink:type="locator" xlink:label="dei_EntityCurrentReportingStatus" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityCurrentReportingStatus_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Current Reporting Status</link:label>
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    <link:label xml:lang="en-US" xlink:label="dei_EntityCurrentReportingStatus_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Current Reporting Status</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityShellCompany" xlink:type="locator" xlink:label="dei_EntityShellCompany" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityShellCompany_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Shell Company</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityShellCompany" xlink:to="dei_EntityShellCompany_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityShellCompany_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Shell Company</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityFilerCategory" xlink:type="locator" xlink:label="dei_EntityFilerCategory" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityFilerCategory_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Entity Filer Category</link:label>
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    <link:label xml:lang="en-US" xlink:label="dei_EntityFilerCategory_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Filer Category</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntitySmallBusiness" xlink:type="locator" xlink:label="dei_EntitySmallBusiness" />
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    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntitySmallBusiness" xlink:to="dei_EntitySmallBusiness_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntitySmallBusiness_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Small Business</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityEmergingGrowthCompany" xlink:type="locator" xlink:label="dei_EntityEmergingGrowthCompany" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityEmergingGrowthCompany_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Emerging Growth Company</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityEmergingGrowthCompany" xlink:to="dei_EntityEmergingGrowthCompany_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityEmergingGrowthCompany_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Emerging Growth Company</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityCommonStockSharesOutstanding" xlink:type="locator" xlink:label="dei_EntityCommonStockSharesOutstanding" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityCommonStockSharesOutstanding_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Common Stock, Shares Outstanding</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityCommonStockSharesOutstanding" xlink:to="dei_EntityCommonStockSharesOutstanding_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityCommonStockSharesOutstanding_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Common Stock Shares Outstanding</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityFileNumber" xlink:type="locator" xlink:label="dei_EntityFileNumber" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityFileNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity File Number</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityFileNumber" xlink:to="dei_EntityFileNumber_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityFileNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity File Number</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityTaxIdentificationNumber" xlink:type="locator" xlink:label="dei_EntityTaxIdentificationNumber" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityTaxIdentificationNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Tax Identification Number</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityTaxIdentificationNumber" xlink:to="dei_EntityTaxIdentificationNumber_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityTaxIdentificationNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Tax Identification Number</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityAddressAddressLine1" xlink:type="locator" xlink:label="dei_EntityAddressAddressLine1" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityAddressAddressLine1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, Address Line One</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityAddressAddressLine1" xlink:to="dei_EntityAddressAddressLine1_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityAddressAddressLine1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address Address Line1</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityAddressCityOrTown" xlink:type="locator" xlink:label="dei_EntityAddressCityOrTown" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityAddressCityOrTown_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, City or Town</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityAddressCityOrTown" xlink:to="dei_EntityAddressCityOrTown_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityAddressCityOrTown_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address City Or Town</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityAddressStateOrProvince" xlink:type="locator" xlink:label="dei_EntityAddressStateOrProvince" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityAddressStateOrProvince_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, State or Province</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityAddressStateOrProvince" xlink:to="dei_EntityAddressStateOrProvince_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityAddressStateOrProvince_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address State Or Province</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityAddressPostalZipCode" xlink:type="locator" xlink:label="dei_EntityAddressPostalZipCode" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityAddressPostalZipCode_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, Postal Zip Code</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityAddressPostalZipCode" xlink:to="dei_EntityAddressPostalZipCode_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityAddressPostalZipCode_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address Postal Zip Code</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_CityAreaCode" xlink:type="locator" xlink:label="dei_CityAreaCode" />
    <link:label xml:lang="en-US" xlink:label="dei_CityAreaCode_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">City Area Code</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_CityAreaCode" xlink:to="dei_CityAreaCode_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_CityAreaCode_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">City Area Code</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_LocalPhoneNumber" xlink:type="locator" xlink:label="dei_LocalPhoneNumber" />
    <link:label xml:lang="en-US" xlink:label="dei_LocalPhoneNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Local Phone Number</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_LocalPhoneNumber" xlink:to="dei_LocalPhoneNumber_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_LocalPhoneNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Local Phone Number</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_Security12bTitle" xlink:type="locator" xlink:label="dei_Security12bTitle" />
    <link:label xml:lang="en-US" xlink:label="dei_Security12bTitle_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Title of 12(b) Security</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_Security12bTitle" xlink:to="dei_Security12bTitle_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_Security12bTitle_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Security12b Title</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_SecurityExchangeName" xlink:type="locator" xlink:label="dei_SecurityExchangeName" />
    <link:label xml:lang="en-US" xlink:label="dei_SecurityExchangeName_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Security Exchange Name</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_SecurityExchangeName" xlink:to="dei_SecurityExchangeName_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_SecurityExchangeName_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Security Exchange Name</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentQuarterlyReport" xlink:type="locator" xlink:label="dei_DocumentQuarterlyReport" />
    <link:label xml:lang="en-US" xlink:label="dei_DocumentQuarterlyReport_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Quarterly Report</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_DocumentQuarterlyReport" xlink:to="dei_DocumentQuarterlyReport_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_DocumentQuarterlyReport_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Document Quarterly Report</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentTransitionReport" xlink:type="locator" xlink:label="dei_DocumentTransitionReport" />
    <link:label xml:lang="en-US" xlink:label="dei_DocumentTransitionReport_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Transition Report</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_DocumentTransitionReport" xlink:to="dei_DocumentTransitionReport_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_DocumentTransitionReport_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Document Transition Report</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityIncorporationStateCountryCode" xlink:type="locator" xlink:label="dei_EntityIncorporationStateCountryCode" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityIncorporationStateCountryCode_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Incorporation, State or Country Code</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityIncorporationStateCountryCode" xlink:to="dei_EntityIncorporationStateCountryCode_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityIncorporationStateCountryCode_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Incorporation State Country Code</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityInteractiveDataCurrent" xlink:type="locator" xlink:label="dei_EntityInteractiveDataCurrent" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityInteractiveDataCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Interactive Data Current</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityInteractiveDataCurrent" xlink:to="dei_EntityInteractiveDataCurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityInteractiveDataCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Interactive Data Current</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_AccruedExpensesAndOtherCurrentLiabilities" xlink:type="locator" xlink:label="psn_AccruedExpensesAndOtherCurrentLiabilities" />
    <link:label xml:lang="en-US" xlink:label="psn_AccruedExpensesAndOtherCurrentLiabilities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Accrued expenses and other current liabilities.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_AccruedExpensesAndOtherCurrentLiabilities" xlink:to="psn_AccruedExpensesAndOtherCurrentLiabilities_lbl" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementOfFinancialPositionAbstract" xlink:type="locator" xlink:label="us-gaap_StatementOfFinancialPositionAbstract" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_StatementOfFinancialPositionAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Statement Of Financial Position [Abstract]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementOfFinancialPositionAbstract" xlink:to="us-gaap_StatementOfFinancialPositionAbstract_lbl" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsAbstract" xlink:type="locator" xlink:label="us-gaap_AssetsAbstract" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AssetsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Assets</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AssetsAbstract" xlink:to="us-gaap_AssetsAbstract_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AssetsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Assets [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:type="locator" xlink:label="us-gaap_AssetsCurrentAbstract" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AssetsCurrentAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current assets:</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AssetsCurrentAbstract" xlink:to="us-gaap_AssetsCurrentAbstract_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AssetsCurrentAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Assets Current [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:type="locator" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash and cash equivalents (including $31,221 and $51,171 Cash of consolidated joint ventures)</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:to="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Cash And Cash Equivalents At Carrying Value</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedCashAndInvestmentsCurrent" xlink:type="locator" xlink:label="us-gaap_RestrictedCashAndInvestmentsCurrent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RestrictedCashAndInvestmentsCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restricted cash and investments</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RestrictedCashAndInvestmentsCurrent" xlink:to="us-gaap_RestrictedCashAndInvestmentsCurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RestrictedCashAndInvestmentsCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Restricted Cash And Investments Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:type="locator" xlink:label="us-gaap_AccountsReceivableNetCurrent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AccountsReceivableNetCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accounts receivable, net (including $257,967 and $166,355 Accounts receivable of consolidated joint ventures, net)</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccountsReceivableNetCurrent" xlink:to="us-gaap_AccountsReceivableNetCurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AccountsReceivableNetCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Accounts Receivable Net Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractWithCustomerAssetNetCurrent" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerAssetNetCurrent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerAssetNetCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/positiveLabel">Contract assets (including $27,010 and $26,458 Contract assets of consolidated joint ventures)</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ContractWithCustomerAssetNetCurrent" xlink:to="us-gaap_ContractWithCustomerAssetNetCurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerAssetNetCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Contract With Customer Asset Net Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:type="locator" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Prepaid expenses and other current assets (including $8,524 and $11,182 Prepaid expenses and other current assets of consolidated joint ventures)</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:to="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Prepaid Expense And Other Assets Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsCurrent" xlink:type="locator" xlink:label="us-gaap_AssetsCurrent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AssetsCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total current assets</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AssetsCurrent" xlink:to="us-gaap_AssetsCurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AssetsCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Assets Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentNet" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/positiveLabel">Property and equipment, net (including $2,672 and $2,945 Property and equipment of consolidated joint ventures, net)</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentNet" xlink:to="us-gaap_PropertyPlantAndEquipmentNet_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Property Plant And Equipment Net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset" xlink:type="locator" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Right of use assets, operating leases</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeaseRightOfUseAsset" xlink:to="us-gaap_OperatingLeaseRightOfUseAsset_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease Right Of Use Asset</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Goodwill" xlink:type="locator" xlink:label="us-gaap_Goodwill" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_Goodwill_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Goodwill</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Goodwill" xlink:to="us-gaap_Goodwill_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_Goodwill_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Goodwill</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:type="locator" xlink:label="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Investments in and advances to unconsolidated joint ventures</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:to="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Investments In Affiliates Subsidiaries Associates And Joint Ventures</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:type="locator" xlink:label="us-gaap_IntangibleAssetsNetExcludingGoodwill" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_IntangibleAssetsNetExcludingGoodwill_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Intangible assets, net</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:to="us-gaap_IntangibleAssetsNetExcludingGoodwill_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_IntangibleAssetsNetExcludingGoodwill_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Intangible Assets Net Excluding Goodwill</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredIncomeTaxAssetsNet" xlink:type="locator" xlink:label="us-gaap_DeferredIncomeTaxAssetsNet" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DeferredIncomeTaxAssetsNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred tax assets</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredIncomeTaxAssetsNet" xlink:to="us-gaap_DeferredIncomeTaxAssetsNet_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DeferredIncomeTaxAssetsNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Income Tax Assets Net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:type="locator" xlink:label="us-gaap_OtherAssetsNoncurrent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OtherAssetsNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other noncurrent assets</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherAssetsNoncurrent" xlink:to="us-gaap_OtherAssetsNoncurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OtherAssetsNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Other Assets Noncurrent</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Assets" xlink:type="locator" xlink:label="us-gaap_Assets" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_Assets_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total assets</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Assets" xlink:to="us-gaap_Assets_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_Assets_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:type="locator" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Liabilities and Shareholders&apos; Equity (Deficit)</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:to="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities And Stockholders Equity [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:type="locator" xlink:label="us-gaap_LiabilitiesCurrentAbstract" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesCurrentAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current liabilities:</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesCurrentAbstract" xlink:to="us-gaap_LiabilitiesCurrentAbstract_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesCurrentAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities Current [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:type="locator" xlink:label="us-gaap_AccountsPayableCurrent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AccountsPayableCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accounts payable (including $91,969 and $85,869 Accounts payable of consolidated joint ventures)</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccountsPayableCurrent" xlink:to="us-gaap_AccountsPayableCurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AccountsPayableCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Accounts Payable Current</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_AccruedExpensesAndOtherCurrentLiabilities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/positiveLabel">Accrued expenses and other current liabilities (including $112,014 and $74,857 Accrued expenses and other current liabilities of consolidated joint ventures)</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_AccruedExpensesAndOtherCurrentLiabilities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Accrued Expenses And Other Current Liabilities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractWithCustomerLiabilityCurrent" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerLiabilityCurrent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiabilityCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/positiveLabel">Contract liabilities (including $41,945 and $32,638 Contract liabilities of consolidated joint ventures)</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ContractWithCustomerLiabilityCurrent" xlink:to="us-gaap_ContractWithCustomerLiabilityCurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiabilityCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Contract With Customer Liability Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseLiabilityCurrent" xlink:type="locator" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Short-term lease liabilities, operating leases</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeaseLiabilityCurrent" xlink:to="us-gaap_OperatingLeaseLiabilityCurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease Liability Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxesPayableCurrent" xlink:type="locator" xlink:label="us-gaap_TaxesPayableCurrent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_TaxesPayableCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income taxes payable</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TaxesPayableCurrent" xlink:to="us-gaap_TaxesPayableCurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_TaxesPayableCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Taxes Payable Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:type="locator" xlink:label="us-gaap_LiabilitiesCurrent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total current liabilities</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_LiabilitiesCurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities Current</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LongTermEmployeeIncentives_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-term employee incentives</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LongTermEmployeeIncentives_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Long Term Employee Incentives</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebt" xlink:type="locator" xlink:label="us-gaap_LongTermDebt" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LongTermDebt_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-term debt</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LongTermDebt" xlink:to="us-gaap_LongTermDebt_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LongTermDebt_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Long Term Debt</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:type="locator" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-term lease liabilities, operating leases</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:to="us-gaap_OperatingLeaseLiabilityNoncurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease Liability Noncurrent</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:type="locator" xlink:label="us-gaap_DeferredIncomeTaxLiabilitiesNet" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DeferredIncomeTaxLiabilitiesNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred tax liabilities</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:to="us-gaap_DeferredIncomeTaxLiabilitiesNet_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DeferredIncomeTaxLiabilitiesNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Income Tax Liabilities Net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:type="locator" xlink:label="us-gaap_OtherLiabilitiesNoncurrent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OtherLiabilitiesNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other long-term liabilities</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherLiabilitiesNoncurrent" xlink:to="us-gaap_OtherLiabilitiesNoncurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OtherLiabilitiesNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Other Liabilities Noncurrent</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Liabilities" xlink:type="locator" xlink:label="us-gaap_Liabilities" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_Liabilities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total liabilities</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Liabilities" xlink:to="us-gaap_Liabilities_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_Liabilities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommitmentsAndContingencies" xlink:type="locator" xlink:label="us-gaap_CommitmentsAndContingencies" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_CommitmentsAndContingencies_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Contingencies (Note 12)</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommitmentsAndContingencies" xlink:to="us-gaap_CommitmentsAndContingencies_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_CommitmentsAndContingencies_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Commitments And Contingencies</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:type="locator" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Shareholders&apos; equity (deficit):</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:to="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Stockholders Equity Including Portion Attributable To Noncontrolling Interest [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockValue" xlink:type="locator" xlink:label="us-gaap_CommonStockValue" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_CommonStockValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, $1 par value; authorized 1,000,000,000 shares; 146,495,690 and 146,440,701 shares issued; 23,929,462 and 21,772,888 public shares outstanding; 76,795,221 and 78,896,806 ESOP shares outstanding</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockValue" xlink:to="us-gaap_CommonStockValue_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_CommonStockValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock Value</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TreasuryStockValue" xlink:type="locator" xlink:label="us-gaap_TreasuryStockValue" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_TreasuryStockValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Treasury stock, 45,771,008 shares at cost</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TreasuryStockValue" xlink:to="us-gaap_TreasuryStockValue_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_TreasuryStockValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Treasury Stock Value</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdditionalPaidInCapitalCommonStock" xlink:type="locator" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Additional paid-in capital</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdditionalPaidInCapitalCommonStock" xlink:to="us-gaap_AdditionalPaidInCapitalCommonStock_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Additional Paid In Capital Common Stock</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:type="locator" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:type="locator" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accumulated other comprehensive loss</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_StockholdersEquity_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Stockholders Equity</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MinorityInterest" xlink:type="locator" xlink:label="us-gaap_MinorityInterest" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_MinorityInterest_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Noncontrolling interests</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MinorityInterest" xlink:to="us-gaap_MinorityInterest_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_MinorityInterest_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Minority Interest</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:type="locator" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total shareholders&apos; equity</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:to="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Stockholders Equity Including Portion Attributable To Noncontrolling Interest</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:type="locator" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total liabilities, redeemable common stock and shareholders&apos; equity</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities And Stockholders Equity</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:type="locator" xlink:label="us-gaap_StatementTable" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_StatementTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statement [Table]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementTable_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_StatementTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Statement [Table]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Related Party</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Related Party Transactions By Related Party [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:type="locator" xlink:label="us-gaap_RelatedPartyDomain" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RelatedPartyDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Related Party</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="us-gaap_RelatedPartyDomain_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RelatedPartyDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Related Party [Domain]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_ConsolidatedJointVenturesMember" xlink:type="locator" xlink:label="psn_ConsolidatedJointVenturesMember" />
    <link:label xml:lang="en-US" xlink:label="psn_ConsolidatedJointVenturesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Consolidated joint ventures.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_ConsolidatedJointVenturesMember" xlink:to="psn_ConsolidatedJointVenturesMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_ConsolidatedJointVenturesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Consolidated Joint Ventures</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ConsolidatedJointVenturesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Consolidated Joint Ventures [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameAxis" xlink:type="locator" xlink:label="us-gaap_PlanNameAxis" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PlanNameAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Plan Name</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_PlanNameAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Plan Name [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameDomain" xlink:type="locator" xlink:label="us-gaap_PlanNameDomain" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PlanNameDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Plan Name</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PlanNameDomain" xlink:to="us-gaap_PlanNameDomain_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PlanNameDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Plan Name [Domain]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_EmployeeStockOwnershipPlanMember" xlink:type="locator" xlink:label="psn_EmployeeStockOwnershipPlanMember" />
    <link:label xml:lang="en-US" xlink:label="psn_EmployeeStockOwnershipPlanMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Employee Stock Ownership Plan.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_EmployeeStockOwnershipPlanMember" xlink:to="psn_EmployeeStockOwnershipPlanMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_EmployeeStockOwnershipPlanMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">ESOP</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_EmployeeStockOwnershipPlanMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Employee Stock Ownership Plan [Member]</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_StatementLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statement [Line Items]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementLineItems_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_StatementLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Statement [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Cash and cash equivalents</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_AccountsReceivableNetCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Accounts receivable, net</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerAssetNetCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Contract assets</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Prepaid expenses and other current assets</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Property and equipment, net</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_AccountsPayableCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Accounts payable</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_AccruedExpensesAndOtherCurrentLiabilities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Accrued expenses and other current liabilities</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiabilityCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Contract liabilities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:type="locator" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, par value</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock Par Or Stated Value Per Share</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:type="locator" xlink:label="us-gaap_CommonStockSharesAuthorized" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_CommonStockSharesAuthorized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, shares authorized</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_CommonStockSharesAuthorized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock Shares Authorized</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_CommonStockSharesIssued_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, shares, issued</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_CommonStockSharesIssued_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock Shares Issued</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, shares, outstanding</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock Shares Outstanding</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_TreasuryStockShares_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Treasury stock, shares</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_TreasuryStockShares_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Treasury Stock Shares</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_OtherIncomeExpense" xlink:type="locator" xlink:label="psn_OtherIncomeExpense" />
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    <link:label xml:lang="en-US" xlink:label="us-gaap_CostOfGoodsAndServicesSold_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Direct cost of contracts</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_CostOfGoodsAndServicesSold_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Cost Of Goods And Services Sold</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:type="locator" xlink:label="us-gaap_IncomeLossFromEquityMethodInvestments" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_IncomeLossFromEquityMethodInvestments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Equity in earnings of unconsolidated joint ventures</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from sale of property and equipment</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment" xlink:to="us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds From Sale Of Property Plant And Equipment</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Payments for acquisitions, net of cash acquired</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:to="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Payments To Acquire Businesses Net Of Cash Acquired</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToAcquireInterestInJointVenture" xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquireInterestInJointVenture" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PaymentsToAcquireInterestInJointVenture_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Investments in unconsolidated joint ventures</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToAcquireInterestInJointVenture" xlink:to="us-gaap_PaymentsToAcquireInterestInJointVenture_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PaymentsToAcquireInterestInJointVenture_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Payments To Acquire Interest In Joint Venture</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital" xlink:type="locator" xlink:label="us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Return of investments in unconsolidated joint ventures</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital" xlink:to="us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds From Equity Method Investment Dividends Or Distributions Return Of Capital</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net cash used in investing activities</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Net Cash Provided By Used In Investing Activities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash flows from financing activities:</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Net Cash Provided By Used In Financing Activities [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromLinesOfCredit" xlink:type="locator" xlink:label="us-gaap_ProceedsFromLinesOfCredit" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromLinesOfCredit_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from borrowings</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromLinesOfCredit" xlink:to="us-gaap_ProceedsFromLinesOfCredit_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromLinesOfCredit_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds From Lines Of Credit</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RepaymentsOfLinesOfCredit" xlink:type="locator" xlink:label="us-gaap_RepaymentsOfLinesOfCredit" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RepaymentsOfLinesOfCredit_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Repayments of borrowings</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RepaymentsOfLinesOfCredit" xlink:to="us-gaap_RepaymentsOfLinesOfCredit_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RepaymentsOfLinesOfCredit_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Repayments Of Lines Of Credit</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsOfDebtIssuanceCosts" xlink:type="locator" xlink:label="us-gaap_PaymentsOfDebtIssuanceCosts" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PaymentsOfDebtIssuanceCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Payments for debt costs and credit agreement</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsOfDebtIssuanceCosts" xlink:to="us-gaap_PaymentsOfDebtIssuanceCosts_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PaymentsOfDebtIssuanceCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Payments Of Debt Issuance Costs</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromMinorityShareholders" xlink:type="locator" xlink:label="us-gaap_ProceedsFromMinorityShareholders" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromMinorityShareholders_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Contributions by noncontrolling interests</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromMinorityShareholders" xlink:to="us-gaap_ProceedsFromMinorityShareholders_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromMinorityShareholders_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds From Minority Shareholders</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToMinorityShareholders" xlink:type="locator" xlink:label="us-gaap_PaymentsToMinorityShareholders" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PaymentsToMinorityShareholders_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Distributions to noncontrolling interests</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToMinorityShareholders" xlink:to="us-gaap_PaymentsToMinorityShareholders_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PaymentsToMinorityShareholders_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Payments To Minority Shareholders</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_PaymentsForPurchaseOfTreasuryStock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Purchase of treasury stock</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_PaymentsForPurchaseOfTreasuryStock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Payments For Purchase Of Treasury Stock</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_PaymentsForTaxesPaidOnVestedStock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Taxes paid on vested stock</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_PaymentsForTaxesPaidOnVestedStock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Payments For Taxes Paid On Vested Stock</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonStock" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonStock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from issuance of common stock</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:to="us-gaap_ProceedsFromIssuanceOfCommonStock_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonStock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds From Issuance Of Common Stock</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsOfDividends" xlink:type="locator" xlink:label="us-gaap_PaymentsOfDividends" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PaymentsOfDividends_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Dividend paid</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsOfDividends" xlink:to="us-gaap_PaymentsOfDividends_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PaymentsOfDividends_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Payments Of Dividends</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net cash (used in) provided by financing activities</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivities_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Net Cash Provided By Used In Financing Activities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsDisposalGroupIncludingDiscontinuedOperations" xlink:type="locator" xlink:label="us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsDisposalGroupIncludingDiscontinuedOperations" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsDisposalGroupIncludingDiscontinuedOperations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Effect of exchange rate changes</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsDisposalGroupIncludingDiscontinuedOperations" xlink:to="us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsDisposalGroupIncludingDiscontinuedOperations_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsDisposalGroupIncludingDiscontinuedOperations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Disposal Group Including Discontinued Operations</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:type="locator" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net decrease in cash, cash equivalents, and restricted cash</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffectAbstract" xlink:type="locator" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffectAbstract" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffectAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash, cash equivalents and restricted cash:</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffectAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations" xlink:type="locator" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Beginning of year</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">End of period</link:label>
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    <link:label xml:lang="en-US" xlink:label="psn_MinorityInterestIncreaseDecreaseFromContributionsToNoncontrollingInterestHolders_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Minority interest increase (decrease) from contributions to noncontrolling interest holders.</link:label>
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    <link:loc xlink:href="psn-20200630.xsd#psn_TemporaryEquityDistributionsAmount" xlink:type="locator" xlink:label="psn_TemporaryEquityDistributionsAmount" />
    <link:label xml:lang="en-US" xlink:label="psn_TemporaryEquityDistributionsAmount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Temporary equity distributions amount.</link:label>
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    <link:loc xlink:href="psn-20200630.xsd#psn_MinorityInterestIncreaseDecreaseFromDistributionsToNoncontrollingInterestHolders" xlink:type="locator" xlink:label="psn_MinorityInterestIncreaseDecreaseFromDistributionsToNoncontrollingInterestHolders" />
    <link:label xml:lang="en-US" xlink:label="psn_MinorityInterestIncreaseDecreaseFromDistributionsToNoncontrollingInterestHolders_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Minority interest increase (decrease) from distributions to noncontrolling interest holders.</link:label>
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    <link:loc xlink:href="psn-20200630.xsd#psn_TemporaryEquityStockIssuedDuringPeriodValueConversionOfUnits" xlink:type="locator" xlink:label="psn_TemporaryEquityStockIssuedDuringPeriodValueConversionOfUnits" />
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    <link:label xml:lang="en-US" xlink:label="us-gaap_EquityComponentDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Equity Component [Domain]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_RedeemableCommonStockMember" xlink:type="locator" xlink:label="psn_RedeemableCommonStockMember" />
    <link:label xml:lang="en-US" xlink:label="psn_RedeemableCommonStockMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Redeemable common stock.</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_CommonStockMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common Stock</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_CommonStockMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock [Member]</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_TreasuryStockMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Treasury Stock</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_TreasuryStockMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Treasury Stock [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:type="locator" xlink:label="us-gaap_AdditionalPaidInCapitalMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AdditionalPaidInCapitalMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Additional Paid-in Capital</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_AdditionalPaidInCapitalMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Additional Paid In Capital [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:type="locator" xlink:label="us-gaap_RetainedEarningsMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RetainedEarningsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Retained Earnings (Accumulated Deficit)</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RetainedEarningsMember" xlink:to="us-gaap_RetainedEarningsMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RetainedEarningsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Retained Earnings [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:type="locator" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accumulated Other Comprehensive Income (Loss)</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Accumulated Other Comprehensive Income [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ParentMember" xlink:type="locator" xlink:label="us-gaap_ParentMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ParentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total Parsons Equity (Deficit)</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ParentMember" xlink:to="us-gaap_ParentMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ParentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Parent [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:type="locator" xlink:label="us-gaap_NoncontrollingInterestMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_NoncontrollingInterestMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Noncontrolling Interest</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NoncontrollingInterestMember" xlink:to="us-gaap_NoncontrollingInterestMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_NoncontrollingInterestMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Noncontrolling Interest [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RestatementAxis" xlink:type="locator" xlink:label="srt_RestatementAxis" />
    <link:label xml:lang="en-US" xlink:label="srt_RestatementAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Revision of Prior Period</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_RestatementAxis" xlink:to="srt_RestatementAxis_lbl" />
    <link:label xml:lang="en-US" xlink:label="srt_RestatementAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Restatement [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RestatementDomain" xlink:type="locator" xlink:label="srt_RestatementDomain" />
    <link:label xml:lang="en-US" xlink:label="srt_RestatementDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Revision of Prior Period</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_RestatementDomain" xlink:to="srt_RestatementDomain_lbl" />
    <link:label xml:lang="en-US" xlink:label="srt_RestatementDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Restatement [Domain]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RevisionOfPriorPeriodAccountingStandardsUpdateAdjustmentMember" xlink:type="locator" xlink:label="srt_RevisionOfPriorPeriodAccountingStandardsUpdateAdjustmentMember" />
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    <link:label xml:lang="en-US" xlink:label="us-gaap_TypeOfAdoptionMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accounting Standards Update</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_TypeOfAdoptionMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Type Of Adoption [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountingStandardsUpdate201613Member" xlink:type="locator" xlink:label="us-gaap_AccountingStandardsUpdate201613Member" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AccountingStandardsUpdate201613Member_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">ASC 2016-13</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountingStandardsUpdate201602Member" xlink:type="locator" xlink:label="us-gaap_AccountingStandardsUpdate201602Member" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AccountingStandardsUpdate201602Member_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">ASC 842</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Beginning balance</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_TemporaryEquityCarryingAmountAttributableToParent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Temporary Equity Carrying Amount Attributable To Parent</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:type="locator" xlink:label="us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterestAbstract" />
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    <link:label xml:lang="en-US" xlink:label="us-gaap_ProfitLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Net income</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" />
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    <link:label xml:lang="en-US" xlink:label="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Pension adjustments, net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod" xlink:type="locator" xlink:label="us-gaap_TreasuryStockValueAcquiredCostMethod" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_TreasuryStockValueAcquiredCostMethod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Purchase of treasury stock</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_TreasuryStockValueAcquiredCostMethod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Treasury Stock Value Acquired Cost Method</link:label>
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    <link:loc xlink:href="psn-20200630.xsd#psn_ScheduleOfMaturitiesOfOperatingAndFinanceLeaseLiabilitiesTableTextBlock" xlink:type="locator" xlink:label="psn_ScheduleOfMaturitiesOfOperatingAndFinanceLeaseLiabilitiesTableTextBlock" />
    <link:label xml:lang="en-US" xlink:label="psn_ScheduleOfMaturitiesOfOperatingAndFinanceLeaseLiabilitiesTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Schedule of maturities of operating and finance lease liabilities.</link:label>
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    <link:loc xlink:href="psn-20200630.xsd#psn_ScheduleOfFinancialInformationOfConsolidatedJointVenturesTableTextBlock" xlink:type="locator" xlink:label="psn_ScheduleOfFinancialInformationOfConsolidatedJointVenturesTableTextBlock" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock" />
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    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock" xlink:to="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock_lbl" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedTextBlock" xlink:type="locator" xlink:label="us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedTextBlock" />
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    <link:loc xlink:href="psn-20200630.xsd#psn_SummaryOfRevenuesAndPropertyAndEquipmentNetByGeographicAreaTableTextBlock" xlink:type="locator" xlink:label="psn_SummaryOfRevenuesAndPropertyAndEquipmentNetByGeographicAreaTableTextBlock" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTextBlock" />
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    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTextBlock" xlink:to="us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTextBlock_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Entity Wide Information Revenue From External Customers By Products And Services [Text Block]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_PurchaseOfAdditionalSharesUponExerciseOfOptions" xlink:type="locator" xlink:label="psn_PurchaseOfAdditionalSharesUponExerciseOfOptions" />
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    <link:loc xlink:href="psn-20200630.xsd#psn_UnderwritingDiscountPerShare" xlink:type="locator" xlink:label="psn_UnderwritingDiscountPerShare" />
    <link:label xml:lang="en-US" xlink:label="psn_UnderwritingDiscountPerShare_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Underwriting discount per share.</link:label>
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    <link:loc xlink:href="psn-20200630.xsd#psn_FundsToDividendsThroughPublicOffering" xlink:type="locator" xlink:label="psn_FundsToDividendsThroughPublicOffering" />
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    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_FundsToDividendsThroughPublicOffering" xlink:to="psn_FundsToDividendsThroughPublicOffering_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_RepaymentOnTermLoanThroughPublicOffering" xlink:type="locator" xlink:label="psn_RepaymentOnTermLoanThroughPublicOffering" />
    <link:label xml:lang="en-US" xlink:label="psn_RepaymentOnTermLoanThroughPublicOffering_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Repayment on term loan through public offering.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_RepaymentOnTermLoanThroughPublicOffering" xlink:to="psn_RepaymentOnTermLoanThroughPublicOffering_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_DescriptionOfOperationsDisclosureLineItems" xlink:type="locator" xlink:label="psn_DescriptionOfOperationsDisclosureLineItems" />
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    <link:loc xlink:href="psn-20200630.xsd#psn_DescriptionOfOperationsDisclosureTable" xlink:type="locator" xlink:label="psn_DescriptionOfOperationsDisclosureTable" />
    <link:label xml:lang="en-US" xlink:label="psn_DescriptionOfOperationsDisclosureTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Description of operations disclosure.</link:label>
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    <link:label xml:lang="en-US" xlink:label="psn_DescriptionOfOperationsDisclosureTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Description Of Operations Disclosure [Table]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsidiarySaleOfStockAxis" xlink:type="locator" xlink:label="us-gaap_SubsidiarySaleOfStockAxis" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_SubsidiarySaleOfStockAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Sale of Stock</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_SubsidiarySaleOfStockAxis_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_SubsidiarySaleOfStockAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Subsidiary Sale Of Stock [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:type="locator" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Sale of Stock</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SaleOfStockNameOfTransactionDomain" xlink:to="us-gaap_SaleOfStockNameOfTransactionDomain_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Sale Of Stock Name Of Transaction [Domain]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IPOMember" xlink:type="locator" xlink:label="us-gaap_IPOMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_IPOMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">IPO</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IPOMember" xlink:to="us-gaap_IPOMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_IPOMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">I P O [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OverAllotmentOptionMember" xlink:type="locator" xlink:label="us-gaap_OverAllotmentOptionMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OverAllotmentOptionMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Underwriters</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OverAllotmentOptionMember" xlink:to="us-gaap_OverAllotmentOptionMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OverAllotmentOptionMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Over Allotment Option [Member]</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_DescriptionOfOperationsDisclosureLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Description Of Operations Disclosure [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_DescriptionOfOperationsDisclosureLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Description Of Operations Disclosure [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesNewIssues" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_StockIssuedDuringPeriodSharesNewIssues_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock shares sold</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:to="us-gaap_StockIssuedDuringPeriodSharesNewIssues_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_StockIssuedDuringPeriodSharesNewIssues_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period Shares New Issues</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SaleOfStockPricePerShare" xlink:type="locator" xlink:label="us-gaap_SaleOfStockPricePerShare" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_SaleOfStockPricePerShare_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock sold per share</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SaleOfStockPricePerShare" xlink:to="us-gaap_SaleOfStockPricePerShare_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_SaleOfStockPricePerShare_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Sale Of Stock Price Per Share</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_PurchaseOfAdditionalSharesUponExerciseOfOptions_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Purchase of additional shares upon exercise of options</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_PurchaseOfAdditionalSharesUponExerciseOfOptions_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Purchase Of Additional Shares Upon Exercise Of Options</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharePrice" xlink:type="locator" xlink:label="us-gaap_SharePrice" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_SharePrice_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share price</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharePrice" xlink:to="us-gaap_SharePrice_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_SharePrice_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Share Price</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_UnderwritingDiscountPerShare_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Underwriting discount per share</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_UnderwritingDiscountPerShare_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Underwriting Discount Per Share</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromIssuanceInitialPublicOffering" xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceInitialPublicOffering" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromIssuanceInitialPublicOffering_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from IPO</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromIssuanceInitialPublicOffering" xlink:to="us-gaap_ProceedsFromIssuanceInitialPublicOffering_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromIssuanceInitialPublicOffering_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds From Issuance Initial Public Offering</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_FundsToDividendsThroughPublicOffering_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Funds to dividend through public offering</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_FundsToDividendsThroughPublicOffering_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Funds To Dividends Through Public Offering</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_RepaymentOnTermLoanThroughPublicOffering_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Repayment on term loan through public offering</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_RepaymentOnTermLoanThroughPublicOffering_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Repayment On Term Loan Through Public Offering</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_CommonStockDividendRatio" xlink:type="locator" xlink:label="psn_CommonStockDividendRatio" />
    <link:label xml:lang="en-US" xlink:label="psn_CommonStockDividendRatio_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Common stock dividend ratio.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_CommonStockDividendRatio" xlink:to="psn_CommonStockDividendRatio_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_DividendPayablePaymentDate" xlink:type="locator" xlink:label="psn_DividendPayablePaymentDate" />
    <link:label xml:lang="en-US" xlink:label="psn_DividendPayablePaymentDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Dividend payable payment date.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_DividendPayablePaymentDate" xlink:to="psn_DividendPayablePaymentDate_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_CommonStockDividendRatio_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock dividend ratio</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_CommonStockDividendRatio_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock Dividend Ratio</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_DividendPayablePaymentDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Dividends payment, date</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_DividendPayablePaymentDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Dividend Payable Payment Date</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_BasisOfPresentationAndPrinciplesOfConsolidationDisclosureLineItems" xlink:type="locator" xlink:label="psn_BasisOfPresentationAndPrinciplesOfConsolidationDisclosureLineItems" />
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    <link:loc xlink:href="psn-20200630.xsd#psn_BasisOfPresentationAndPrinciplesOfConsolidationDisclosureTable" xlink:type="locator" xlink:label="psn_BasisOfPresentationAndPrinciplesOfConsolidationDisclosureTable" />
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    <link:label xml:lang="en-US" xlink:label="psn_BasisOfPresentationAndPrinciplesOfConsolidationDisclosureTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Basis Of Presentation And Principles Of Consolidation Disclosure [Table]</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_BasisOfPresentationAndPrinciplesOfConsolidationDisclosureTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Basis Of Presentation And Principles Of Consolidation Disclosure [Table]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_EmployeeStockPurchasePlanMember" xlink:type="locator" xlink:label="psn_EmployeeStockPurchasePlanMember" />
    <link:label xml:lang="en-US" xlink:label="psn_EmployeeStockPurchasePlanMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Employee stock purchase plan.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_EmployeeStockPurchasePlanMember" xlink:to="psn_EmployeeStockPurchasePlanMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_EmployeeStockPurchasePlanMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Employee Stock Purchase Plan</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_EmployeeStockPurchasePlanMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Employee Stock Purchase Plan [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:type="locator" xlink:label="srt_RangeAxis" />
    <link:label xml:lang="en-US" xlink:label="srt_RangeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statistical Measurement</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_RangeAxis" xlink:to="srt_RangeAxis_lbl" />
    <link:label xml:lang="en-US" xlink:label="srt_RangeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Range [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:type="locator" xlink:label="srt_RangeMember" />
    <link:label xml:lang="en-US" xlink:label="srt_RangeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statistical Measurement</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_RangeMember" xlink:to="srt_RangeMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="srt_RangeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Range [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:type="locator" xlink:label="srt_MinimumMember" />
    <link:label xml:lang="en-US" xlink:label="srt_MinimumMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Minimum</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_MinimumMember" xlink:to="srt_MinimumMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="srt_MinimumMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Minimum [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:type="locator" xlink:label="srt_MaximumMember" />
    <link:label xml:lang="en-US" xlink:label="srt_MaximumMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maximum</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_MaximumMember" xlink:to="srt_MaximumMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="srt_MaximumMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Maximum [Member]</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_BasisOfPresentationAndPrinciplesOfConsolidationDisclosureLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Basis Of Presentation And Principles Of Consolidation Disclosure [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_BasisOfPresentationAndPrinciplesOfConsolidationDisclosureLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Basis Of Presentation And Principles Of Consolidation Disclosure [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage of per-share market value limit for share purchases</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Share Based Compensation Arrangement By Share Based Payment Award Discount From Market Price Purchase Date</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NewAccountingPronouncementsAndChangesInAccountingPrinciplesAbstract" xlink:type="locator" xlink:label="us-gaap_NewAccountingPronouncementsAndChangesInAccountingPrinciplesAbstract" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_NewAccountingPronouncementsAndChangesInAccountingPrinciplesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">New Accounting Pronouncements And Changes In Accounting Principles [Abstract]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NewAccountingPronouncementsAndChangesInAccountingPrinciplesAbstract" xlink:to="us-gaap_NewAccountingPronouncementsAndChangesInAccountingPrinciplesAbstract_lbl" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable" xlink:type="locator" xlink:label="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">New Accounting Pronouncements Or Change In Accounting Principle [Table]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable" xlink:to="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">New Accounting Pronouncements Or Change In Accounting Principle [Table]</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_AccountingStandardsUpdate201613Member_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">ASU 2016-13</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" xlink:type="locator" xlink:label="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">New Accounting Pronouncements Or Change In Accounting Principle [Line Items]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" xlink:to="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">New Accounting Pronouncements Or Change In Accounting Principle [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ChangeInAccountingPrincipleAccountingStandardsUpdateAdopted" xlink:type="locator" xlink:label="us-gaap_ChangeInAccountingPrincipleAccountingStandardsUpdateAdopted" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ChangeInAccountingPrincipleAccountingStandardsUpdateAdopted_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Change in accounting principle, accounting standards update, adopted</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ChangeInAccountingPrincipleAccountingStandardsUpdateAdopted" xlink:to="us-gaap_ChangeInAccountingPrincipleAccountingStandardsUpdateAdopted_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ChangeInAccountingPrincipleAccountingStandardsUpdateAdopted_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Change In Accounting Principle Accounting Standards Update Adopted</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ChangeInAccountingPrincipleAccountingStandardsUpdateImmaterialEffect" xlink:type="locator" xlink:label="us-gaap_ChangeInAccountingPrincipleAccountingStandardsUpdateImmaterialEffect" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ChangeInAccountingPrincipleAccountingStandardsUpdateImmaterialEffect_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Change in accounting principle, accounting standards update, immaterial effect</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ChangeInAccountingPrincipleAccountingStandardsUpdateImmaterialEffect" xlink:to="us-gaap_ChangeInAccountingPrincipleAccountingStandardsUpdateImmaterialEffect_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ChangeInAccountingPrincipleAccountingStandardsUpdateImmaterialEffect_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Change In Accounting Principle Accounting Standards Update Immaterial Effect</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Business Acquisitions By Acquisition [Table]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Business Acquisitions By Acquisition [Table]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermDebtTypeAxis" xlink:type="locator" xlink:label="us-gaap_ShortTermDebtTypeAxis" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ShortTermDebtTypeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Short-term Debt, Type</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShortTermDebtTypeAxis" xlink:to="us-gaap_ShortTermDebtTypeAxis_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ShortTermDebtTypeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Short Term Debt Type [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermDebtTypeDomain" xlink:type="locator" xlink:label="us-gaap_ShortTermDebtTypeDomain" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ShortTermDebtTypeDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Short-term Debt, Type</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShortTermDebtTypeDomain" xlink:to="us-gaap_ShortTermDebtTypeDomain_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ShortTermDebtTypeDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Short Term Debt Type [Domain]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_TermLoanMember" xlink:type="locator" xlink:label="psn_TermLoanMember" />
    <link:label xml:lang="en-US" xlink:label="psn_TermLoanMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Term loan.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_TermLoanMember" xlink:to="psn_TermLoanMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_TermLoanMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Term Loan</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_TermLoanMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Term Loan [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationAxis" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_IncomeStatementLocationAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income Statement Location</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeStatementLocationAxis" xlink:to="us-gaap_IncomeStatementLocationAxis_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_IncomeStatementLocationAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Income Statement Location [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationDomain" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_IncomeStatementLocationDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income Statement Location</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeStatementLocationDomain" xlink:to="us-gaap_IncomeStatementLocationDomain_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_IncomeStatementLocationDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Income Statement Location [Domain]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_IndirectGeneralAndAdministrativeExpenseMember" xlink:type="locator" xlink:label="psn_IndirectGeneralAndAdministrativeExpenseMember" />
    <link:label xml:lang="en-US" xlink:label="psn_IndirectGeneralAndAdministrativeExpenseMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Indirect, General and Administrative Expense.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_IndirectGeneralAndAdministrativeExpenseMember" xlink:to="psn_IndirectGeneralAndAdministrativeExpenseMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_IndirectGeneralAndAdministrativeExpenseMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Indirect, General and Administrative Expense</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_IndirectGeneralAndAdministrativeExpenseMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Indirect General And Administrative Expense [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:type="locator" xlink:label="us-gaap_CreditFacilityAxis" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_CreditFacilityAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Credit Facility</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CreditFacilityAxis" xlink:to="us-gaap_CreditFacilityAxis_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_CreditFacilityAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Credit Facility [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:type="locator" xlink:label="us-gaap_CreditFacilityDomain" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_CreditFacilityDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Credit Facility</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="us-gaap_CreditFacilityDomain_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_CreditFacilityDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Credit Facility [Domain]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:type="locator" xlink:label="us-gaap_RevolvingCreditFacilityMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RevolvingCreditFacilityMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Revolving Credit Facility</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_RevolvingCreditFacilityMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Revolving Credit Facility [Member]</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_BusinessAcquisitionLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Business Acquisition [Line Items]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessAcquisitionLineItems_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_BusinessAcquisitionLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Business Acquisition [Line Items]</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage of ownership interest acquired</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross" xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquireBusinessesGross" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PaymentsToAcquireBusinessesGross_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash paid to acquire</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_NoncompeteAgreementsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Non compete Agreements</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NoncompeteAgreementsMember" xlink:to="us-gaap_NoncompeteAgreementsMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_NoncompeteAgreementsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Noncompete Agreements [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DevelopedTechnologyRightsMember" xlink:type="locator" xlink:label="us-gaap_DevelopedTechnologyRightsMember" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InProcessResearchAndDevelopmentMember" xlink:type="locator" xlink:label="us-gaap_InProcessResearchAndDevelopmentMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_InProcessResearchAndDevelopmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">In-Process Research and Development</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InProcessResearchAndDevelopmentMember" xlink:to="us-gaap_InProcessResearchAndDevelopmentMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_InProcessResearchAndDevelopmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">In Process Research And Development [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems" xlink:type="locator" xlink:label="us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Acquired Finite Lived Intangible Assets [Line Items]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems" xlink:to="us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Acquired Finite Lived Intangible Assets [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinitelivedIntangibleAssetsAcquired1" xlink:type="locator" xlink:label="us-gaap_FinitelivedIntangibleAssetsAcquired1" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinitelivedIntangibleAssetsAcquired1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Gross Carrying Amount</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinitelivedIntangibleAssetsAcquired1" xlink:to="us-gaap_FinitelivedIntangibleAssetsAcquired1_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinitelivedIntangibleAssetsAcquired1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finitelived Intangible Assets Acquired1</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" xlink:type="locator" xlink:label="us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Amortization Period (in years)</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" xlink:to="us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Acquired Finite Lived Intangible Assets Weighted Average Useful Life</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:type="locator" xlink:label="us-gaap_AmortizationOfIntangibleAssets" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AmortizationOfIntangibleAssets_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Amortization of intangible assets</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AmortizationOfIntangibleAssets" xlink:to="us-gaap_AmortizationOfIntangibleAssets_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AmortizationOfIntangibleAssets_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Amortization Of Intangible Assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Goodwill deductible for tax purposes</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount" xlink:to="us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Business Acquisition Purchase Price Allocation Goodwill Expected Tax Deductible Amount</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Revenues</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_BusinessAcquisitionProFormaNetIncomeLossIncludingPortionAttributableToNoncontrollingInterest" xlink:type="locator" xlink:label="psn_BusinessAcquisitionProFormaNetIncomeLossIncludingPortionAttributableToNoncontrollingInterest" />
    <link:label xml:lang="en-US" xlink:label="psn_BusinessAcquisitionProFormaNetIncomeLossIncludingPortionAttributableToNoncontrollingInterest_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Business acquisition, pro forma net income (loss), including portion attributable to noncontrolling interest.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_BusinessAcquisitionProFormaNetIncomeLossIncludingPortionAttributableToNoncontrollingInterest" xlink:to="psn_BusinessAcquisitionProFormaNetIncomeLossIncludingPortionAttributableToNoncontrollingInterest_lbl" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionsProFormaRevenue" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionsProFormaRevenue" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_BusinessAcquisitionsProFormaRevenue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Pro forma revenue</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessAcquisitionsProFormaRevenue" xlink:to="us-gaap_BusinessAcquisitionsProFormaRevenue_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_BusinessAcquisitionsProFormaRevenue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Business Acquisitions Pro Forma Revenue</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_BusinessAcquisitionProFormaNetIncomeLossIncludingPortionAttributableToNoncontrollingInterest_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Pro forma net income including noncontrolling interests</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_BusinessAcquisitionProFormaNetIncomeLossIncludingPortionAttributableToNoncontrollingInterest_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Business Acquisition Pro Forma Net Income Loss Including Portion Attributable To Noncontrolling Interest</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:type="locator" xlink:label="us-gaap_DisaggregationOfRevenueTable" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DisaggregationOfRevenueTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Disaggregation Of Revenue [Table]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DisaggregationOfRevenueTable" xlink:to="us-gaap_DisaggregationOfRevenueTable_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DisaggregationOfRevenueTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Disaggregation Of Revenue [Table]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractWithCustomerBasisOfPricingAxis" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerBasisOfPricingAxis" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerBasisOfPricingAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Contract with Customer, Basis of Pricing</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ContractWithCustomerBasisOfPricingAxis" xlink:to="us-gaap_ContractWithCustomerBasisOfPricingAxis_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerBasisOfPricingAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Contract With Customer Basis Of Pricing [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractWithCustomerBasisOfPricingDomain" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerBasisOfPricingDomain" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerBasisOfPricingDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Contract with Customer, Basis of Pricing</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ContractWithCustomerBasisOfPricingDomain" xlink:to="us-gaap_ContractWithCustomerBasisOfPricingDomain_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerBasisOfPricingDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Contract With Customer Basis Of Pricing [Domain]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FixedPriceContractMember" xlink:type="locator" xlink:label="us-gaap_FixedPriceContractMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FixedPriceContractMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fixed-Price</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FixedPriceContractMember" xlink:to="us-gaap_FixedPriceContractMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FixedPriceContractMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Fixed Price Contract [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TimeAndMaterialsContractMember" xlink:type="locator" xlink:label="us-gaap_TimeAndMaterialsContractMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_TimeAndMaterialsContractMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Time-and-Materials</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TimeAndMaterialsContractMember" xlink:to="us-gaap_TimeAndMaterialsContractMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_TimeAndMaterialsContractMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Time And Materials Contract [Member]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_CostPlusMember" xlink:type="locator" xlink:label="psn_CostPlusMember" />
    <link:label xml:lang="en-US" xlink:label="psn_CostPlusMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Cost plus.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_CostPlusMember" xlink:to="psn_CostPlusMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_CostPlusMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cost-Plus</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_CostPlusMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Cost Plus [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:type="locator" xlink:label="us-gaap_DisaggregationOfRevenueLineItems" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DisaggregationOfRevenueLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Disaggregation Of Revenue [Line Items]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DisaggregationOfRevenueLineItems" xlink:to="us-gaap_DisaggregationOfRevenueLineItems_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DisaggregationOfRevenueLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Disaggregation Of Revenue [Line Items]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_ContractWithCustomerAssetLiabilityNet" xlink:type="locator" xlink:label="psn_ContractWithCustomerAssetLiabilityNet" />
    <link:label xml:lang="en-US" xlink:label="psn_ContractWithCustomerAssetLiabilityNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Contract with customer asset and liabilities net.</link:label>
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    <link:label xml:lang="en-US" xlink:label="psn_ChangeInContractWithCustomerAssetsAndLiabilitiesNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Change in contract with customer assets and liabilities net.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_ChangeInContractWithCustomerAssetsAndLiabilitiesNet" xlink:to="psn_ChangeInContractWithCustomerAssetsAndLiabilitiesNet_lbl" />
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    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_ChangeInContractWithCustomerAssets" xlink:to="psn_ChangeInContractWithCustomerAssets_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_ChangeInContractWithCustomerLiability" xlink:type="locator" xlink:label="psn_ChangeInContractWithCustomerLiability" />
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    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_ChangeInContractWithCustomerLiability" xlink:to="psn_ChangeInContractWithCustomerLiability_lbl" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractWithCustomerAssetNet" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerAssetNet" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerAssetNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Contract assets</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ContractWithCustomerAssetNet" xlink:to="us-gaap_ContractWithCustomerAssetNet_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerAssetNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Contract With Customer Asset Net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractWithCustomerLiability" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerLiability" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Contract liabilities</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ContractWithCustomerLiability" xlink:to="us-gaap_ContractWithCustomerLiability_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Contract With Customer Liability</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ContractWithCustomerAssetLiabilityNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net contract assets (liabilities)</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ContractWithCustomerAssetLiabilityNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Contract With Customer Asset Liability Net</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ChangeInContractWithCustomerAssets_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Change in contract assets</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ChangeInContractWithCustomerAssets_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Change In Contract With Customer Assets</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ChangeInContractWithCustomerLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Change in contract liabilities</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ChangeInContractWithCustomerLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Change In Contract With Customer Liability</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ChangeInContractWithCustomerAssetsAndLiabilitiesNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Change in contract assets and liabilities</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ChangeInContractWithCustomerAssetsAndLiabilitiesNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Change In Contract With Customer Assets And Liabilities Net</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_ContractWithCustomerAssetCumulativeCatchupAdjustmentToRevenueChangeInMeasureOfProgressPercent" xlink:type="locator" xlink:label="psn_ContractWithCustomerAssetCumulativeCatchupAdjustmentToRevenueChangeInMeasureOfProgressPercent" />
    <link:label xml:lang="en-US" xlink:label="psn_ContractWithCustomerAssetCumulativeCatchupAdjustmentToRevenueChangeInMeasureOfProgressPercent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Contract with customer asset cumulative catchup adjustment to revenue change in measure of progress percent.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_ContractWithCustomerAssetCumulativeCatchupAdjustmentToRevenueChangeInMeasureOfProgressPercent" xlink:to="psn_ContractWithCustomerAssetCumulativeCatchupAdjustmentToRevenueChangeInMeasureOfProgressPercent_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_ContractWithCustomerLiabilityCumulativeCatchupAdjustmentToRevenueChangeInMeasureOfProgressPercent" xlink:type="locator" xlink:label="psn_ContractWithCustomerLiabilityCumulativeCatchupAdjustmentToRevenueChangeInMeasureOfProgressPercent" />
    <link:label xml:lang="en-US" xlink:label="psn_ContractWithCustomerLiabilityCumulativeCatchupAdjustmentToRevenueChangeInMeasureOfProgressPercent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Contract with customer liability cumulative catchup adjustment to revenue change in measure of progress percent.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_ContractWithCustomerLiabilityCumulativeCatchupAdjustmentToRevenueChangeInMeasureOfProgressPercent" xlink:to="psn_ContractWithCustomerLiabilityCumulativeCatchupAdjustmentToRevenueChangeInMeasureOfProgressPercent_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_ContractWithCustomerAssetLiabilityCumulativeCatchupAdjustmentToRevenueChangeInMeasureOfProgressPercent" xlink:type="locator" xlink:label="psn_ContractWithCustomerAssetLiabilityCumulativeCatchupAdjustmentToRevenueChangeInMeasureOfProgressPercent" />
    <link:label xml:lang="en-US" xlink:label="psn_ContractWithCustomerAssetLiabilityCumulativeCatchupAdjustmentToRevenueChangeInMeasureOfProgressPercent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Contract with customer asset cumulative catchup adjustment to revenue change in measure of progress percent.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_ContractWithCustomerAssetLiabilityCumulativeCatchupAdjustmentToRevenueChangeInMeasureOfProgressPercent" xlink:to="psn_ContractWithCustomerAssetLiabilityCumulativeCatchupAdjustmentToRevenueChangeInMeasureOfProgressPercent_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_ContractWithCustomerAssetCumulativeCatchupAdjustmentToRevenueChangeInMeasureOfProgressPercent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage change in contract assets</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ContractWithCustomerAssetCumulativeCatchupAdjustmentToRevenueChangeInMeasureOfProgressPercent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Contract With Customer Asset Cumulative Catchup Adjustment To Revenue Change In Measure Of Progress Percent</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ContractWithCustomerLiabilityCumulativeCatchupAdjustmentToRevenueChangeInMeasureOfProgressPercent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage change in contract liabilities</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ContractWithCustomerLiabilityCumulativeCatchupAdjustmentToRevenueChangeInMeasureOfProgressPercent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Contract With Customer Liability Cumulative Catchup Adjustment To Revenue Change In Measure Of Progress Percent</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ContractWithCustomerAssetLiabilityCumulativeCatchupAdjustmentToRevenueChangeInMeasureOfProgressPercent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage change in contract assets and liabilities</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ContractWithCustomerAssetLiabilityCumulativeCatchupAdjustmentToRevenueChangeInMeasureOfProgressPercent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Contract With Customer Asset Liability Cumulative Catchup Adjustment To Revenue Change In Measure Of Progress Percent</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_ContractReceivableRetainageAssetsLiabilitiesNet" xlink:type="locator" xlink:label="psn_ContractReceivableRetainageAssetsLiabilitiesNet" />
    <link:label xml:lang="en-US" xlink:label="psn_ContractReceivableRetainageAssetsLiabilitiesNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Contract receivable retainage assets (Liabilities) net.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_ContractReceivableRetainageAssetsLiabilitiesNet" xlink:to="psn_ContractReceivableRetainageAssetsLiabilitiesNet_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_ContractReceivableRetainageAssetLiabilitiesNetDueAfterOneYear" xlink:type="locator" xlink:label="psn_ContractReceivableRetainageAssetLiabilitiesNetDueAfterOneYear" />
    <link:label xml:lang="en-US" xlink:label="psn_ContractReceivableRetainageAssetLiabilitiesNetDueAfterOneYear_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Contract receivable retainage asset (liabilities) net, due after one year.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_ContractReceivableRetainageAssetLiabilitiesNetDueAfterOneYear" xlink:to="psn_ContractReceivableRetainageAssetLiabilitiesNetDueAfterOneYear_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_ContractReceivableRetainageAssetsLiabilitiesNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Contract retentions</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ContractReceivableRetainageAssetsLiabilitiesNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Contract Receivable Retainage Assets Liabilities Net</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ContractReceivableRetainageAssetLiabilitiesNetDueAfterOneYear_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Contract retentions, not expected to be paid in next 12 months</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ContractReceivableRetainageAssetLiabilitiesNetDueAfterOneYear_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Contract Receivable Retainage Asset Liabilities Net Due After One Year</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractsReceivableClaimsAndUncertainAmounts" xlink:type="locator" xlink:label="us-gaap_ContractsReceivableClaimsAndUncertainAmounts" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractsReceivableClaimsAndUncertainAmounts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Contract assets, unapproved change orders, claims, and requests</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ContractsReceivableClaimsAndUncertainAmounts" xlink:to="us-gaap_ContractsReceivableClaimsAndUncertainAmounts_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractsReceivableClaimsAndUncertainAmounts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Contracts Receivable Claims And Uncertain Amounts</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractWithCustomerLiabilityRevenueRecognized" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerLiabilityRevenueRecognized" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiabilityRevenueRecognized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Revenue recognized included contract liability</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ContractWithCustomerLiabilityRevenueRecognized" xlink:to="us-gaap_ContractWithCustomerLiabilityRevenueRecognized_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiabilityRevenueRecognized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Contract With Customer Liability Revenue Recognized</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractWithCustomerAssetIncreaseDecreaseForContractAcquiredInBusinessCombination" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerAssetIncreaseDecreaseForContractAcquiredInBusinessCombination" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerAssetIncreaseDecreaseForContractAcquiredInBusinessCombination_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Acquired contract assets</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ContractWithCustomerAssetIncreaseDecreaseForContractAcquiredInBusinessCombination" xlink:to="us-gaap_ContractWithCustomerAssetIncreaseDecreaseForContractAcquiredInBusinessCombination_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerAssetIncreaseDecreaseForContractAcquiredInBusinessCombination_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Contract With Customer Asset Increase Decrease For Contract Acquired In Business Combination</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractWithCustomerLiabilityIncreaseDecreaseForContractAcquiredInBusinessCombination" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerLiabilityIncreaseDecreaseForContractAcquiredInBusinessCombination" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiabilityIncreaseDecreaseForContractAcquiredInBusinessCombination_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Acquired contract liabilities</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ContractWithCustomerLiabilityIncreaseDecreaseForContractAcquiredInBusinessCombination" xlink:to="us-gaap_ContractWithCustomerLiabilityIncreaseDecreaseForContractAcquiredInBusinessCombination_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiabilityIncreaseDecreaseForContractAcquiredInBusinessCombination_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Contract With Customer Liability Increase Decrease For Contract Acquired In Business Combination</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInEstimateOfTransactionPrice" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInEstimateOfTransactionPrice" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInEstimateOfTransactionPrice_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Change in the estimate of variable consideration</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInEstimateOfTransactionPrice" xlink:to="us-gaap_ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInEstimateOfTransactionPrice_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInEstimateOfTransactionPrice_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Contract With Customer Liability Cumulative Catch Up Adjustment To Revenue Change In Estimate Of Transaction Price</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalizedContractCostImpairmentLoss" xlink:type="locator" xlink:label="us-gaap_CapitalizedContractCostImpairmentLoss" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_CapitalizedContractCostImpairmentLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Impairment of contract assets</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CapitalizedContractCostImpairmentLoss" xlink:to="us-gaap_CapitalizedContractCostImpairmentLoss_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_CapitalizedContractCostImpairmentLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Capitalized Contract Cost Impairment Loss</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_ContractWithCustomerAdjustmentToRevenueImpactOfChangesInEstimatedClaimsOrIncentivesOverThreshold" xlink:type="locator" xlink:label="psn_ContractWithCustomerAdjustmentToRevenueImpactOfChangesInEstimatedClaimsOrIncentivesOverThreshold" />
    <link:label xml:lang="en-US" xlink:label="psn_ContractWithCustomerAdjustmentToRevenueImpactOfChangesInEstimatedClaimsOrIncentivesOverThreshold_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Contract with customer adjustment to revenue impact of changes in estimated claims or incentives over threshold.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_ContractWithCustomerAdjustmentToRevenueImpactOfChangesInEstimatedClaimsOrIncentivesOverThreshold" xlink:to="psn_ContractWithCustomerAdjustmentToRevenueImpactOfChangesInEstimatedClaimsOrIncentivesOverThreshold_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_ContractWithCustomerAdjustmentToRevenueImpactOfChangesInEstimatedClaimsOrIncentivesOverThreshold_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Impact of changes in estimated claims or incentives on revenue</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ContractWithCustomerAdjustmentToRevenueImpactOfChangesInEstimatedClaimsOrIncentivesOverThreshold_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Contract With Customer Adjustment To Revenue Impact Of Changes In Estimated Claims Or Incentives Over Threshold</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgress" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgress" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgress_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Increase in revenue due to Impact of changes in estimated claims or incentives</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgress" xlink:to="us-gaap_ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgress_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgress_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Contract With Customer Liability Cumulative Catch Up Adjustment To Revenue Change In Measure Of Progress</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_BilledReceivablesCurrent" xlink:type="locator" xlink:label="psn_BilledReceivablesCurrent" />
    <link:label xml:lang="en-US" xlink:label="psn_BilledReceivablesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Billed receivables current.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_BilledReceivablesCurrent" xlink:to="psn_BilledReceivablesCurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_BilledReceivablesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Billed</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_BilledReceivablesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Billed Receivables Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnbilledReceivablesCurrent" xlink:type="locator" xlink:label="us-gaap_UnbilledReceivablesCurrent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_UnbilledReceivablesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unbilled</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_UnbilledReceivablesCurrent" xlink:to="us-gaap_UnbilledReceivablesCurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_UnbilledReceivablesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Unbilled Receivables Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsReceivableGrossCurrent" xlink:type="locator" xlink:label="us-gaap_AccountsReceivableGrossCurrent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AccountsReceivableGrossCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total accounts receivable, gross</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccountsReceivableGrossCurrent" xlink:to="us-gaap_AccountsReceivableGrossCurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AccountsReceivableGrossCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Accounts Receivable Gross Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:type="locator" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Allowance for doubtful accounts</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:to="us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Allowance For Doubtful Accounts Receivable Current</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_AccountsReceivableNetCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total accounts receivable, net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligation" xlink:type="locator" xlink:label="us-gaap_RevenueRemainingPerformanceObligation" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RevenueRemainingPerformanceObligation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Remaining unsatisfied performance obligations</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RevenueRemainingPerformanceObligation" xlink:to="us-gaap_RevenueRemainingPerformanceObligation_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RevenueRemainingPerformanceObligation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Revenue Remaining Performance Obligation</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable" xlink:type="locator" xlink:label="us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Table]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable" xlink:to="us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Table]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:type="locator" xlink:label="us-gaap_StatementBusinessSegmentsAxis" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_StatementBusinessSegmentsAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Segments</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementBusinessSegmentsAxis" xlink:to="us-gaap_StatementBusinessSegmentsAxis_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_StatementBusinessSegmentsAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Statement Business Segments [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain" xlink:type="locator" xlink:label="us-gaap_SegmentDomain" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_SegmentDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Segments</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SegmentDomain" xlink:to="us-gaap_SegmentDomain_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_SegmentDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Segment [Domain]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_FederalSolutionSegmentMember" xlink:type="locator" xlink:label="psn_FederalSolutionSegmentMember" />
    <link:label xml:lang="en-US" xlink:label="psn_FederalSolutionSegmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Federal Solution Segment.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_FederalSolutionSegmentMember" xlink:to="psn_FederalSolutionSegmentMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_FederalSolutionSegmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal Solution Segment</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_FederalSolutionSegmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Federal Solution Segment [Member]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_CriticalInfrastructureSegmentMember" xlink:type="locator" xlink:label="psn_CriticalInfrastructureSegmentMember" />
    <link:label xml:lang="en-US" xlink:label="psn_CriticalInfrastructureSegmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Critical Infrastructure Segment.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_CriticalInfrastructureSegmentMember" xlink:to="psn_CriticalInfrastructureSegmentMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_CriticalInfrastructureSegmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Critical Infrastructure</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_CriticalInfrastructureSegmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Critical Infrastructure Segment [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis" xlink:type="locator" xlink:label="us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis" xlink:to="us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Start Date [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems" xlink:type="locator" xlink:label="us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems" xlink:to="us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1" xlink:type="locator" xlink:label="us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Revenue, remaining performance obligation, expected timing of satisfaction, period</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1" xlink:to="us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_LesseeLeaseTermOfContract" xlink:type="locator" xlink:label="psn_LesseeLeaseTermOfContract" />
    <link:label xml:lang="en-US" xlink:label="psn_LesseeLeaseTermOfContract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Lessee lease term of contract.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_LesseeLeaseTermOfContract" xlink:to="psn_LesseeLeaseTermOfContract_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_LesseeLeaseOptionToExtend" xlink:type="locator" xlink:label="psn_LesseeLeaseOptionToExtend" />
    <link:label xml:lang="en-US" xlink:label="psn_LesseeLeaseOptionToExtend_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Lessee lease option to extend.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_LesseeLeaseOptionToExtend" xlink:to="psn_LesseeLeaseOptionToExtend_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_LesseeLeaseOptionToTerminate" xlink:type="locator" xlink:label="psn_LesseeLeaseOptionToTerminate" />
    <link:label xml:lang="en-US" xlink:label="psn_LesseeLeaseOptionToTerminate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Lessee lease option to terminate.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_LesseeLeaseOptionToTerminate" xlink:to="psn_LesseeLeaseOptionToTerminate_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_LesseeLeaseExistenceOfOptionToExtend" xlink:type="locator" xlink:label="psn_LesseeLeaseExistenceOfOptionToExtend" />
    <link:label xml:lang="en-US" xlink:label="psn_LesseeLeaseExistenceOfOptionToExtend_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Lessee lease existence of option to extend.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_LesseeLeaseExistenceOfOptionToExtend" xlink:to="psn_LesseeLeaseExistenceOfOptionToExtend_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_LesseeLeaseExistenceOfOptionToTerminate" xlink:type="locator" xlink:label="psn_LesseeLeaseExistenceOfOptionToTerminate" />
    <link:label xml:lang="en-US" xlink:label="psn_LesseeLeaseExistenceOfOptionToTerminate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Lessee lease existence of option to terminate.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_LesseeLeaseExistenceOfOptionToTerminate" xlink:to="psn_LesseeLeaseExistenceOfOptionToTerminate_lbl" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeLeaseDescriptionTable" xlink:type="locator" xlink:label="us-gaap_LesseeLeaseDescriptionTable" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LesseeLeaseDescriptionTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lessee Lease Description [Table]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeLeaseDescriptionTable" xlink:to="us-gaap_LesseeLeaseDescriptionTable_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LesseeLeaseDescriptionTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Lessee Lease Description [Table]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeLeaseDescriptionLineItems" xlink:type="locator" xlink:label="us-gaap_LesseeLeaseDescriptionLineItems" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LesseeLeaseDescriptionLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lessee Lease Description [Line Items]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeLeaseDescriptionLineItems" xlink:to="us-gaap_LesseeLeaseDescriptionLineItems_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LesseeLeaseDescriptionLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Lessee Lease Description [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LesseeLeaseTermOfContract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lease term of contract</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LesseeLeaseTermOfContract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Lessee Lease Term Of Contract</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LesseeLeaseOptionToExtend_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lease option to extend</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LesseeLeaseOptionToExtend_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Lessee Lease Option To Extend</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LesseeLeaseExistenceOfOptionToExtend_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lease existence of option to extend</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LesseeLeaseExistenceOfOptionToExtend_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Lessee Lease Existence Of Option To Extend</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LesseeLeaseOptionToTerminate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lease option to terminate</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LesseeLeaseOptionToTerminate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Lessee Lease Option To Terminate</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LesseeLeaseExistenceOfOptionToTerminate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lease existence of option to terminate</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LesseeLeaseExistenceOfOptionToTerminate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Lessee Lease Existence Of Option To Terminate</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseCost" xlink:type="locator" xlink:label="us-gaap_OperatingLeaseCost" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseCost_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating lease cost</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeaseCost" xlink:to="us-gaap_OperatingLeaseCost_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseCost_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease Cost</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermLeaseCost" xlink:type="locator" xlink:label="us-gaap_ShortTermLeaseCost" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ShortTermLeaseCost_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Short-term lease cost</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShortTermLeaseCost" xlink:to="us-gaap_ShortTermLeaseCost_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ShortTermLeaseCost_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Short Term Lease Cost</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseRightOfUseAssetAmortization" xlink:type="locator" xlink:label="us-gaap_FinanceLeaseRightOfUseAssetAmortization" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseRightOfUseAssetAmortization_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Amortization of right-of-use assets</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLeaseRightOfUseAssetAmortization" xlink:to="us-gaap_FinanceLeaseRightOfUseAssetAmortization_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseRightOfUseAssetAmortization_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Lease Right Of Use Asset Amortization</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseInterestExpense" xlink:type="locator" xlink:label="us-gaap_FinanceLeaseInterestExpense" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseInterestExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest on lease liabilities</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLeaseInterestExpense" xlink:to="us-gaap_FinanceLeaseInterestExpense_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseInterestExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Lease Interest Expense</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubleaseIncome" xlink:type="locator" xlink:label="us-gaap_SubleaseIncome" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_SubleaseIncome_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Sublease income</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SubleaseIncome" xlink:to="us-gaap_SubleaseIncome_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_SubleaseIncome_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Sublease Income</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LeaseCost" xlink:type="locator" xlink:label="us-gaap_LeaseCost" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LeaseCost_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total lease cost</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LeaseCost" xlink:to="us-gaap_LeaseCost_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LeaseCost_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Lease Cost</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeasePayments" xlink:type="locator" xlink:label="us-gaap_OperatingLeasePayments" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeasePayments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating cash flows for operating leases</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasePayments" xlink:to="us-gaap_OperatingLeasePayments_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeasePayments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease Payments</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseInterestPaymentOnLiability" xlink:type="locator" xlink:label="us-gaap_FinanceLeaseInterestPaymentOnLiability" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseInterestPaymentOnLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Operating cash flows for financing activities</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLeaseInterestPaymentOnLiability" xlink:to="us-gaap_FinanceLeaseInterestPaymentOnLiability_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseInterestPaymentOnLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Lease Interest Payment On Liability</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeasePrincipalPayments" xlink:type="locator" xlink:label="us-gaap_FinanceLeasePrincipalPayments" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeasePrincipalPayments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financing cash flows from finance leases</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLeasePrincipalPayments" xlink:to="us-gaap_FinanceLeasePrincipalPayments_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeasePrincipalPayments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Lease Principal Payments</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability" xlink:type="locator" xlink:label="us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Right-of-use assets obtained in exchange for new operating lease liabilities</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability" xlink:to="us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Right Of Use Asset Obtained In Exchange For Operating Lease Liability</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability" xlink:type="locator" xlink:label="us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Right-of-use assets obtained in exchange for new finance lease liabilities</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability" xlink:to="us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Right Of Use Asset Obtained In Exchange For Finance Lease Liability</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_OperatingLeasesAbstract" xlink:type="locator" xlink:label="psn_OperatingLeasesAbstract" />
    <link:label xml:lang="en-US" xlink:label="psn_OperatingLeasesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Operating lease.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_OperatingLeasesAbstract" xlink:to="psn_OperatingLeasesAbstract_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_LeaseLiabilitiesAbstract" xlink:type="locator" xlink:label="psn_LeaseLiabilitiesAbstract" />
    <link:label xml:lang="en-US" xlink:label="psn_LeaseLiabilitiesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Lease liabilities.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_LeaseLiabilitiesAbstract" xlink:to="psn_LeaseLiabilitiesAbstract_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_FinanceLeasesAbstract" xlink:type="locator" xlink:label="psn_FinanceLeasesAbstract" />
    <link:label xml:lang="en-US" xlink:label="psn_FinanceLeasesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Finance leases.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_FinanceLeasesAbstract" xlink:to="psn_FinanceLeasesAbstract_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_FinanceLeasesOtherAssetsNoncurrent" xlink:type="locator" xlink:label="psn_FinanceLeasesOtherAssetsNoncurrent" />
    <link:label xml:lang="en-US" xlink:label="psn_FinanceLeasesOtherAssetsNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Finance leases other assets noncurrent.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_FinanceLeasesOtherAssetsNoncurrent" xlink:to="psn_FinanceLeasesOtherAssetsNoncurrent_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_WeightedAverageRemainingLeaseTermAbstract" xlink:type="locator" xlink:label="psn_WeightedAverageRemainingLeaseTermAbstract" />
    <link:label xml:lang="en-US" xlink:label="psn_WeightedAverageRemainingLeaseTermAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Weighted average remaining lease term.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_WeightedAverageRemainingLeaseTermAbstract" xlink:to="psn_WeightedAverageRemainingLeaseTermAbstract_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_WeightedAverageDiscountRateAbstract" xlink:type="locator" xlink:label="psn_WeightedAverageDiscountRateAbstract" />
    <link:label xml:lang="en-US" xlink:label="psn_WeightedAverageDiscountRateAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Weighted average discount rate.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_WeightedAverageDiscountRateAbstract" xlink:to="psn_WeightedAverageDiscountRateAbstract_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_OperatingLeasesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating Leases:</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_OperatingLeasesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Operating Leases [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Right-of-use assets</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LeaseLiabilitiesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lease liabilities:</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LeaseLiabilitiesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Lease Liabilities [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Current</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Long-term</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseLiability" xlink:type="locator" xlink:label="us-gaap_OperatingLeaseLiability" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total operating lease liabilities</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeaseLiability" xlink:to="us-gaap_OperatingLeaseLiability_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease Liability</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_FinanceLeasesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Finance Leases:</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_FinanceLeasesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Leases [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_FinanceLeasesOtherAssetsNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other noncurrent assets</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_FinanceLeasesOtherAssetsNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Leases Other Assets Noncurrent</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseLiabilityCurrent" xlink:type="locator" xlink:label="us-gaap_FinanceLeaseLiabilityCurrent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accrued expenses and other current liabilities</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLeaseLiabilityCurrent" xlink:to="us-gaap_FinanceLeaseLiabilityCurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Lease Liability Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList" xlink:type="locator" xlink:label="us-gaap_FinanceLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList" xlink:to="us-gaap_FinanceLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Lease Liability Current Statement Of Financial Position Extensible List</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseLiabilityNoncurrent" xlink:type="locator" xlink:label="us-gaap_FinanceLeaseLiabilityNoncurrent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other long-term liabilities</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLeaseLiabilityNoncurrent" xlink:to="us-gaap_FinanceLeaseLiabilityNoncurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Lease Liability Noncurrent</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList" xlink:type="locator" xlink:label="us-gaap_FinanceLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList" xlink:to="us-gaap_FinanceLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Lease Liability Noncurrent Statement Of Financial Position Extensible List</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_WeightedAverageRemainingLeaseTermAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted Average Remaining Lease Term:</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_WeightedAverageRemainingLeaseTermAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Weighted Average Remaining Lease Term [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1" xlink:type="locator" xlink:label="us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating leases</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1" xlink:to="us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease Weighted Average Remaining Lease Term1</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1" xlink:type="locator" xlink:label="us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Finance leases</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1" xlink:to="us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Lease Weighted Average Remaining Lease Term1</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_WeightedAverageDiscountRateAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted Average Discount Rate:</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_WeightedAverageDiscountRateAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Weighted Average Discount Rate [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent" xlink:type="locator" xlink:label="us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating leases</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent" xlink:to="us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease Weighted Average Discount Rate Percent</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseWeightedAverageDiscountRatePercent" xlink:type="locator" xlink:label="us-gaap_FinanceLeaseWeightedAverageDiscountRatePercent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseWeightedAverageDiscountRatePercent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Finance leases</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLeaseWeightedAverageDiscountRatePercent" xlink:to="us-gaap_FinanceLeaseWeightedAverageDiscountRatePercent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseWeightedAverageDiscountRatePercent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Lease Weighted Average Discount Rate Percent</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_OperatingLeaseNotYetCommencedExpense" xlink:type="locator" xlink:label="psn_OperatingLeaseNotYetCommencedExpense" />
    <link:label xml:lang="en-US" xlink:label="psn_OperatingLeaseNotYetCommencedExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Operating lease not yet commenced expense.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_OperatingLeaseNotYetCommencedExpense" xlink:to="psn_OperatingLeaseNotYetCommencedExpense_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_OperatingLeaseNotYetCommencedExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating lease not yet commenced expense</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_OperatingLeaseNotYetCommencedExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease Not Yet Commenced Expense</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1" xlink:type="locator" xlink:label="us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating lease not yet commenced term of contract</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1" xlink:to="us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Lessee Operating Lease Lease Not Yet Commenced Term Of Contract1</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract" xlink:type="locator" xlink:label="us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating Leases</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract" xlink:to="us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease Liabilities Payments Due [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear" xlink:type="locator" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2020 (remaining)</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Lessee Operating Lease Liability Payments Remainder Of Fiscal Year</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:type="locator" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2021</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Lessee Operating Lease Liability Payments Due Next Twelve Months</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:type="locator" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2022</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Lessee Operating Lease Liability Payments Due Year Two</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:type="locator" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2023</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Lessee Operating Lease Liability Payments Due Year Three</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:type="locator" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2024</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Lessee Operating Lease Liability Payments Due Year Four</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Thereafter</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Lessee Operating Lease Liability Payments Due After Year Four</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:type="locator" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total lease payments</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Lessee Operating Lease Liability Payments Due</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:type="locator" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Less: imputed interest</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Lessee Operating Lease Liability Undiscounted Excess Amount</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total present value of lease liabilities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract" xlink:type="locator" xlink:label="us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Finance Leases</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract" xlink:to="us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Lease Liabilities Payments Due [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear" xlink:type="locator" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2020 (remaining)</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear" xlink:to="us-gaap_FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Lease Liability Payments Remainder Of Fiscal Year</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:type="locator" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2021</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:to="us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Lease Liability Payments Due Next Twelve Months</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo" xlink:type="locator" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2022</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo" xlink:to="us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Lease Liability Payments Due Year Two</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree" xlink:type="locator" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2023</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree" xlink:to="us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Lease Liability Payments Due Year Three</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour" xlink:type="locator" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2024</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour" xlink:to="us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Lease Liability Payments Due Year Four</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_FinanceLeaseLiabilityPaymentsDueAfterYearFour_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Thereafter</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_FinanceLeaseLiabilityPaymentsDueAfterYearFour_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Lease Liability Payments Due After Year Four</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDue" xlink:type="locator" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDue" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total lease payments</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLeaseLiabilityPaymentsDue" xlink:to="us-gaap_FinanceLeaseLiabilityPaymentsDue_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Lease Liability Payments Due</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:type="locator" xlink:label="us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Less: imputed interest</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:to="us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Lease Liability Undiscounted Excess Amount</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseLiability" xlink:type="locator" xlink:label="us-gaap_FinanceLeaseLiability" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total present value of lease liabilities</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLeaseLiability" xlink:to="us-gaap_FinanceLeaseLiability_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FinanceLeaseLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finance Lease Liability</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfGoodwillTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfGoodwillTable" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfGoodwillTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Goodwill [Table]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfGoodwillTable" xlink:to="us-gaap_ScheduleOfGoodwillTable_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfGoodwillTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Goodwill [Table]</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_FederalSolutionSegmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Federal Solutions</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GoodwillLineItems" xlink:type="locator" xlink:label="us-gaap_GoodwillLineItems" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_GoodwillLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Goodwill [Line Items]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GoodwillLineItems" xlink:to="us-gaap_GoodwillLineItems_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_GoodwillLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Goodwill [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_Goodwill_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Beginning Balance</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GoodwillForeignCurrencyTranslationGainLoss" xlink:type="locator" xlink:label="us-gaap_GoodwillForeignCurrencyTranslationGainLoss" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_GoodwillForeignCurrencyTranslationGainLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Foreign Exchange</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GoodwillForeignCurrencyTranslationGainLoss" xlink:to="us-gaap_GoodwillForeignCurrencyTranslationGainLoss_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_GoodwillForeignCurrencyTranslationGainLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Goodwill Foreign Currency Translation Gain Loss</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_Goodwill_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Ending Balance</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GoodwillImpairmentLoss" xlink:type="locator" xlink:label="us-gaap_GoodwillImpairmentLoss" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_GoodwillImpairmentLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Impairment of goodwill</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GoodwillImpairmentLoss" xlink:to="us-gaap_GoodwillImpairmentLoss_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_GoodwillImpairmentLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Goodwill Impairment Loss</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Acquired Finite Lived Intangible Asset By Major Class [Table]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable" xlink:to="us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Acquired Finite Lived Intangible Asset By Major Class [Table]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LeaseAgreementsMember" xlink:type="locator" xlink:label="us-gaap_LeaseAgreementsMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LeaseAgreementsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Leases</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LeaseAgreementsMember" xlink:to="us-gaap_LeaseAgreementsMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LeaseAgreementsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Lease Agreements [Member]</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_DevelopedTechnologyRightsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Developed Technology</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_InProcessResearchAndDevelopmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">In Process Research and Development</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherIntangibleAssetsMember" xlink:type="locator" xlink:label="us-gaap_OtherIntangibleAssetsMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OtherIntangibleAssetsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Intangibles</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherIntangibleAssetsMember" xlink:to="us-gaap_OtherIntangibleAssetsMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_OtherIntangibleAssetsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Other Intangible Assets [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsGross" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsGross_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Gross Carrying Amount</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsGross" xlink:to="us-gaap_FiniteLivedIntangibleAssetsGross_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsGross_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finite Lived Intangible Assets Gross</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Accumulated Amortization</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finite Lived Intangible Assets Accumulated Amortization</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net Carrying Amount</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsNet" xlink:to="us-gaap_FiniteLivedIntangibleAssetsNet_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finite Lived Intangible Assets Net</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_AmortizationOfIntangibleAssets_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Amortization expense of intangible assets</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_FiniteLivedIntangibleAssetsAmortizableAmount" xlink:type="locator" xlink:label="psn_FiniteLivedIntangibleAssetsAmortizableAmount" />
    <link:label xml:lang="en-US" xlink:label="psn_FiniteLivedIntangibleAssetsAmortizableAmount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Finite lived intangible assets amortizable amount.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_FiniteLivedIntangibleAssetsAmortizableAmount" xlink:to="psn_FiniteLivedIntangibleAssetsAmortizableAmount_lbl" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2020 (remaining)</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finite Lived Intangible Assets Amortization Expense Remainder Of Fiscal Year</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2021</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finite Lived Intangible Assets Amortization Expense Year Two</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2022</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finite Lived Intangible Assets Amortization Expense Year Three</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2023</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finite Lived Intangible Assets Amortization Expense Year Four</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2024</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finite Lived Intangible Assets Amortization Expense Year Five</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Thereafter</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finite Lived Intangible Assets Amortization Expense After Year Five</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_FiniteLivedIntangibleAssetsAmortizableAmount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Finite-Lived Intangible Assets, Net</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_FiniteLivedIntangibleAssetsAmortizableAmount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Finite Lived Intangible Assets Amortizable Amount</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Property Plant And Equipment [Table]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:to="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Property Plant And Equipment [Table]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-Lived Tangible Asset</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="us-gaap_PropertyPlantAndEquipmentByTypeAxis_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Property Plant And Equipment By Type [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-Lived Tangible Asset</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_PropertyPlantAndEquipmentTypeDomain_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Property Plant And Equipment Type [Domain]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BuildingAndBuildingImprovementsMember" xlink:type="locator" xlink:label="us-gaap_BuildingAndBuildingImprovementsMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_BuildingAndBuildingImprovementsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Buildings and Leasehold Improvements</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BuildingAndBuildingImprovementsMember" xlink:to="us-gaap_BuildingAndBuildingImprovementsMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_BuildingAndBuildingImprovementsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Building And Building Improvements [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:type="locator" xlink:label="us-gaap_FurnitureAndFixturesMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FurnitureAndFixturesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Furniture and Equipment</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FurnitureAndFixturesMember" xlink:to="us-gaap_FurnitureAndFixturesMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FurnitureAndFixturesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Furniture And Fixtures [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ComputerEquipmentMember" xlink:type="locator" xlink:label="us-gaap_ComputerEquipmentMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ComputerEquipmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Computer Systems and Equipment</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ComputerEquipmentMember" xlink:to="us-gaap_ComputerEquipmentMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ComputerEquipmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Computer Equipment [Member]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_ConstructionEquipmentMember" xlink:type="locator" xlink:label="psn_ConstructionEquipmentMember" />
    <link:label xml:lang="en-US" xlink:label="psn_ConstructionEquipmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Construction equipment.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_ConstructionEquipmentMember" xlink:to="psn_ConstructionEquipmentMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_ConstructionEquipmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Construction Equipment</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ConstructionEquipmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Construction Equipment [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Property Plant And Equipment [Line Items]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentLineItems" xlink:to="us-gaap_PropertyPlantAndEquipmentLineItems_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Property Plant And Equipment [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentGross" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Property and equipment, gross</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentGross" xlink:to="us-gaap_PropertyPlantAndEquipmentGross_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Property Plant And Equipment Gross</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:type="locator" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Accumulated depreciation</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Accumulated Depreciation Depletion And Amortization Property Plant And Equipment</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Property and equipment, net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Useful lives (years)</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:to="us-gaap_PropertyPlantAndEquipmentUsefulLife_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Property Plant And Equipment Useful Life</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Depreciation" xlink:type="locator" xlink:label="us-gaap_Depreciation" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_Depreciation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Depreciation expense</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Depreciation" xlink:to="us-gaap_Depreciation_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_Depreciation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Depreciation</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentTable" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Instrument [Table]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_DebtInstrumentTable_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument [Table]</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_LongtermDebtTypeDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-term Debt, Type</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LongtermDebtTypeDomain" xlink:to="us-gaap_LongtermDebtTypeDomain_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LongtermDebtTypeDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Longterm Debt Type [Domain]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SeniorNotesMember" xlink:type="locator" xlink:label="us-gaap_SeniorNotesMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_SeniorNotesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Senior Notes</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SeniorNotesMember" xlink:to="us-gaap_SeniorNotesMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_SeniorNotesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Senior Notes [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentLineItems" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Instrument [Line Items]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentLineItems_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentCarryingAmount" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentCarryingAmount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-term debt</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentCarryingAmount" xlink:to="us-gaap_DebtInstrumentCarryingAmount_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentCarryingAmount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Carrying Amount</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredFinanceCostsNoncurrentNet" xlink:type="locator" xlink:label="us-gaap_DeferredFinanceCostsNoncurrentNet" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DeferredFinanceCostsNoncurrentNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Long-Term Debt issuance costs</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredFinanceCostsNoncurrentNet" xlink:to="us-gaap_DeferredFinanceCostsNoncurrentNet_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DeferredFinanceCostsNoncurrentNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Finance Costs Noncurrent Net</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_LongTermDebt_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total long-term</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_LineOfCreditFacilityExtendedDate" xlink:type="locator" xlink:label="psn_LineOfCreditFacilityExtendedDate" />
    <link:label xml:lang="en-US" xlink:label="psn_LineOfCreditFacilityExtendedDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Line of credit facility extended date.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_LineOfCreditFacilityExtendedDate" xlink:to="psn_LineOfCreditFacilityExtendedDate_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_CreditAgreementMember" xlink:type="locator" xlink:label="psn_CreditAgreementMember" />
    <link:label xml:lang="en-US" xlink:label="psn_CreditAgreementMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Credit agreement.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_CreditAgreementMember" xlink:to="psn_CreditAgreementMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_CreditAgreementMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Credit Agreement</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_CreditAgreementMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Credit Agreement [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateAxis" xlink:type="locator" xlink:label="us-gaap_VariableRateAxis" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_VariableRateAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Variable Rate</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_VariableRateAxis" xlink:to="us-gaap_VariableRateAxis_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_VariableRateAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Variable Rate [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateDomain" xlink:type="locator" xlink:label="us-gaap_VariableRateDomain" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_VariableRateDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Variable Rate</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_VariableRateDomain" xlink:to="us-gaap_VariableRateDomain_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_VariableRateDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Variable Rate [Domain]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BaseRateMember" xlink:type="locator" xlink:label="us-gaap_BaseRateMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_BaseRateMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Base Rate</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BaseRateMember" xlink:to="us-gaap_BaseRateMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_BaseRateMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Base Rate [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember" xlink:type="locator" xlink:label="us-gaap_LondonInterbankOfferedRateLIBORMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LondonInterbankOfferedRateLIBORMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">LIBOR</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LondonInterbankOfferedRateLIBORMember" xlink:to="us-gaap_LondonInterbankOfferedRateLIBORMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LondonInterbankOfferedRateLIBORMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">London Interbank Offered Rate L I B O R [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PrivatePlacementMember" xlink:type="locator" xlink:label="us-gaap_PrivatePlacementMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PrivatePlacementMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Private Placement</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PrivatePlacementMember" xlink:to="us-gaap_PrivatePlacementMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_PrivatePlacementMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Private Placement [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:type="locator" xlink:label="us-gaap_BalanceSheetLocationAxis" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_BalanceSheetLocationAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Balance Sheet Location</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_BalanceSheetLocationAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Balance Sheet Location [Axis]</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_BalanceSheetLocationDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Balance Sheet Location</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BalanceSheetLocationDomain" xlink:to="us-gaap_BalanceSheetLocationDomain_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_BalanceSheetLocationDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Balance Sheet Location [Domain]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_AccruedExpensesAndOtherCurrentLiabilitiesMember" xlink:type="locator" xlink:label="psn_AccruedExpensesAndOtherCurrentLiabilitiesMember" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:type="locator" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis" />
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    <link:label xml:lang="en-US" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Measurements Fair Value Hierarchy [Domain]</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_FairValueInputsLevel2Member_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Level 2</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueInputsLevel2Member" xlink:to="us-gaap_FairValueInputsLevel2Member_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_FairValueInputsLevel2Member_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Inputs Level2 [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementScenarioAxis" xlink:type="locator" xlink:label="srt_StatementScenarioAxis" />
    <link:label xml:lang="en-US" xlink:label="srt_StatementScenarioAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Scenario</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_StatementScenarioAxis" xlink:to="srt_StatementScenarioAxis_lbl" />
    <link:label xml:lang="en-US" xlink:label="srt_StatementScenarioAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Statement Scenario [Axis]</link:label>
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    <link:label xml:lang="en-US" xlink:label="srt_ScenarioUnspecifiedDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Scenario</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_ScenarioUnspecifiedDomain" xlink:to="srt_ScenarioUnspecifiedDomain_lbl" />
    <link:label xml:lang="en-US" xlink:label="srt_ScenarioUnspecifiedDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Scenario Unspecified [Domain]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioForecastMember" xlink:type="locator" xlink:label="srt_ScenarioForecastMember" />
    <link:label xml:lang="en-US" xlink:label="srt_ScenarioForecastMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Forecast</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_ScenarioForecastMember" xlink:to="srt_ScenarioForecastMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="srt_ScenarioForecastMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Scenario Forecast [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityInitiationDate1" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityInitiationDate1" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LineOfCreditFacilityInitiationDate1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Amended and restated credit agreement date</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityInitiationDate1" xlink:to="us-gaap_LineOfCreditFacilityInitiationDate1_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LineOfCreditFacilityInitiationDate1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Line Of Credit Facility Initiation Date1</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_DeferredFinanceCostsNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt issuance costs incurred</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_DeferredFinanceCostsNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Finance Costs Net</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Revolving credit facility</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity" xlink:to="us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Line Of Credit Facility Current Borrowing Capacity</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Increase in revolving credit facility</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:to="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Line Of Credit Facility Maximum Borrowing Capacity</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LineOfCreditFacilityExtendedDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Credit agreement extended date</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LineOfCreditFacilityExtendedDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Line Of Credit Facility Extended Date</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Margin interest rate</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:to="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Basis Spread On Variable Rate1</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest rate</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:to="us-gaap_DebtInstrumentInterestRateStatedPercentage_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Interest Rate Stated Percentage</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount" xlink:type="locator" xlink:label="us-gaap_LettersOfCreditOutstandingAmount" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LettersOfCreditOutstandingAmount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Letters of credit outstanding amount</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LettersOfCreditOutstandingAmount" xlink:to="us-gaap_LettersOfCreditOutstandingAmount_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LettersOfCreditOutstandingAmount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Letters Of Credit Outstanding Amount</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseDebt" xlink:type="locator" xlink:label="us-gaap_InterestExpenseDebt" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_InterestExpenseDebt_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest expense</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestExpenseDebt" xlink:to="us-gaap_InterestExpenseDebt_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_InterestExpenseDebt_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Interest Expense Debt</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentCarryingAmount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Debt instrument, outstanding amount</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RepaymentsOfDebt" xlink:type="locator" xlink:label="us-gaap_RepaymentsOfDebt" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RepaymentsOfDebt_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Repayment of outstanding balance</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RepaymentsOfDebt" xlink:to="us-gaap_RepaymentsOfDebt_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_RepaymentsOfDebt_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Repayments Of Debt</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_SeriesASeniorNoteMember" xlink:type="locator" xlink:label="psn_SeriesASeniorNoteMember" />
    <link:label xml:lang="en-US" xlink:label="psn_SeriesASeniorNoteMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Series A senior note.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_SeriesASeniorNoteMember" xlink:to="psn_SeriesASeniorNoteMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_SeriesASeniorNoteMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Senior Note, Series A</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_SeriesASeniorNoteMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Series A Senior Note [Member]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_SeriesBSeniorNoteMember" xlink:type="locator" xlink:label="psn_SeriesBSeniorNoteMember" />
    <link:label xml:lang="en-US" xlink:label="psn_SeriesBSeniorNoteMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Series B senior note.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_SeriesBSeniorNoteMember" xlink:to="psn_SeriesBSeniorNoteMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_SeriesBSeniorNoteMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Senior Note, Series B</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_SeriesBSeniorNoteMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Series B Senior Note [Member]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_SeriesCSeniorNoteMember" xlink:type="locator" xlink:label="psn_SeriesCSeniorNoteMember" />
    <link:label xml:lang="en-US" xlink:label="psn_SeriesCSeniorNoteMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Series C senior note.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_SeriesCSeniorNoteMember" xlink:to="psn_SeriesCSeniorNoteMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_SeriesCSeniorNoteMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Senior Note, Series C</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_SeriesCSeniorNoteMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Series C Senior Note [Member]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_SeriesDSeniorNoteMember" xlink:type="locator" xlink:label="psn_SeriesDSeniorNoteMember" />
    <link:label xml:lang="en-US" xlink:label="psn_SeriesDSeniorNoteMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Series D senior note.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_SeriesDSeniorNoteMember" xlink:to="psn_SeriesDSeniorNoteMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_SeriesDSeniorNoteMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Senior Note, Series D</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_SeriesDSeniorNoteMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Series D Senior Note [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentFaceAmount" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentFaceAmount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Amount</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentFaceAmount" xlink:to="us-gaap_DebtInstrumentFaceAmount_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentFaceAmount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Face Amount</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentMaturityDate" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentMaturityDate" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentMaturityDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maturity Date</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentMaturityDate" xlink:to="us-gaap_DebtInstrumentMaturityDate_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentMaturityDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Maturity Date</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentInterestRateDuringPeriod" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentInterestRateDuringPeriod" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentInterestRateDuringPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest Rates</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentInterestRateDuringPeriod" xlink:to="us-gaap_DebtInstrumentInterestRateDuringPeriod_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentInterestRateDuringPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Interest Rate During Period</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentPeriodicPayment" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentPeriodicPayment" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentPeriodicPayment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest payments</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentPeriodicPayment" xlink:to="us-gaap_DebtInstrumentPeriodicPayment_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentPeriodicPayment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Periodic Payment</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestPayableCurrent" xlink:type="locator" xlink:label="us-gaap_InterestPayableCurrent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_InterestPayableCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest payable</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestPayableCurrent" xlink:to="us-gaap_InterestPayableCurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_InterestPayableCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Interest Payable Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesPayableFairValueDisclosure" xlink:type="locator" xlink:label="us-gaap_NotesPayableFairValueDisclosure" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_NotesPayableFairValueDisclosure_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Senior notes, fair value</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NotesPayableFairValueDisclosure" xlink:to="us-gaap_NotesPayableFairValueDisclosure_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_NotesPayableFairValueDisclosure_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Notes Payable Fair Value Disclosure</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_PercentageOfNetOperatingLossCarryforwardsToOffsetOfTaxableIncomeDuringPeriod" xlink:type="locator" xlink:label="psn_PercentageOfNetOperatingLossCarryforwardsToOffsetOfTaxableIncomeDuringPeriod" />
    <link:label xml:lang="en-US" xlink:label="psn_PercentageOfNetOperatingLossCarryforwardsToOffsetOfTaxableIncomeDuringPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage of net operating loss carryforwards to offset of taxable income during a period.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_PercentageOfNetOperatingLossCarryforwardsToOffsetOfTaxableIncomeDuringPeriod" xlink:to="psn_PercentageOfNetOperatingLossCarryforwardsToOffsetOfTaxableIncomeDuringPeriod_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_AllowableBusinessInterestDeductionPercentageOfAdjustedTaxableIncome" xlink:type="locator" xlink:label="psn_AllowableBusinessInterestDeductionPercentageOfAdjustedTaxableIncome" />
    <link:label xml:lang="en-US" xlink:label="psn_AllowableBusinessInterestDeductionPercentageOfAdjustedTaxableIncome_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Allowable business interest deduction percentage of adjusted taxable income.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_AllowableBusinessInterestDeductionPercentageOfAdjustedTaxableIncome" xlink:to="psn_AllowableBusinessInterestDeductionPercentageOfAdjustedTaxableIncome_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_OperatingLossCarryforwardsDescription" xlink:type="locator" xlink:label="psn_OperatingLossCarryforwardsDescription" />
    <link:label xml:lang="en-US" xlink:label="psn_OperatingLossCarryforwardsDescription_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Operating loss carryforwards description.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_OperatingLossCarryforwardsDescription" xlink:to="psn_OperatingLossCarryforwardsDescription_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_IncomeTaxesLineItems" xlink:type="locator" xlink:label="psn_IncomeTaxesLineItems" />
    <link:label xml:lang="en-US" xlink:label="psn_IncomeTaxesLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Income taxes.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_IncomeTaxesLineItems" xlink:to="psn_IncomeTaxesLineItems_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_IncomeTaxesTable" xlink:type="locator" xlink:label="psn_IncomeTaxesTable" />
    <link:label xml:lang="en-US" xlink:label="psn_IncomeTaxesTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Income taxes.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_IncomeTaxesTable" xlink:to="psn_IncomeTaxesTable_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_IncomeTaxesTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income Taxes [Table]</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_IncomeTaxesTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Income Taxes [Table]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatutoryAccountingPracticesByJurisdictionAxis" xlink:type="locator" xlink:label="us-gaap_StatutoryAccountingPracticesByJurisdictionAxis" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_StatutoryAccountingPracticesByJurisdictionAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Jurisdiction</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatutoryAccountingPracticesByJurisdictionAxis" xlink:to="us-gaap_StatutoryAccountingPracticesByJurisdictionAxis_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_StatutoryAccountingPracticesByJurisdictionAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Statutory Accounting Practices By Jurisdiction [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatutoryAccountingPracticesJurisdictionDomain" xlink:type="locator" xlink:label="us-gaap_StatutoryAccountingPracticesJurisdictionDomain" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_StatutoryAccountingPracticesJurisdictionDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statutory Accounting Practices, Jurisdiction</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatutoryAccountingPracticesJurisdictionDomain" xlink:to="us-gaap_StatutoryAccountingPracticesJurisdictionDomain_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_StatutoryAccountingPracticesJurisdictionDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Statutory Accounting Practices Jurisdiction [Domain]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_CoronavirusAidReliefAndEconomicSecurityActMember" xlink:type="locator" xlink:label="psn_CoronavirusAidReliefAndEconomicSecurityActMember" />
    <link:label xml:lang="en-US" xlink:label="psn_CoronavirusAidReliefAndEconomicSecurityActMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Coronavirus aid, relief, and economic security act.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_CoronavirusAidReliefAndEconomicSecurityActMember" xlink:to="psn_CoronavirusAidReliefAndEconomicSecurityActMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_CoronavirusAidReliefAndEconomicSecurityActMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">CARES Act</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_CoronavirusAidReliefAndEconomicSecurityActMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Coronavirus Aid Relief And Economic Security Act [Member]</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_IncomeTaxesLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income Taxes [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_IncomeTaxesLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Income Taxes [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_PercentageOfNetOperatingLossCarryforwardsToOffsetOfTaxableIncomeDuringPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage of net operating loss (NOL) carryovers to offset of taxable income</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_PercentageOfNetOperatingLossCarryforwardsToOffsetOfTaxableIncomeDuringPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Of Net Operating Loss Carryforwards To Offset Of Taxable Income During Period</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_AllowableBusinessInterestDeductionPercentageOfAdjustedTaxableIncome_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Allowable business interest deduction percentage of adjusted taxable income</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_AllowableBusinessInterestDeductionPercentageOfAdjustedTaxableIncome_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Allowable Business Interest Deduction Percentage Of Adjusted Taxable Income</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_OperatingLossCarryforwardsDescription_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating loss carryforwards description</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_OperatingLossCarryforwardsDescription_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Operating Loss Carryforwards Description</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_DeferredIncomeTaxExpenseBenefitRelatedToRemeasurementDueToChangeInTaxStatus" xlink:type="locator" xlink:label="psn_DeferredIncomeTaxExpenseBenefitRelatedToRemeasurementDueToChangeInTaxStatus" />
    <link:label xml:lang="en-US" xlink:label="psn_DeferredIncomeTaxExpenseBenefitRelatedToRemeasurementDueToChangeInTaxStatus_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Deferred income tax expense benefit related to remeasurement due to change in tax status.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_DeferredIncomeTaxExpenseBenefitRelatedToRemeasurementDueToChangeInTaxStatus" xlink:to="psn_DeferredIncomeTaxExpenseBenefitRelatedToRemeasurementDueToChangeInTaxStatus_lbl" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:type="locator" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Effective income tax rate</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateContinuingOperations_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Effective Income Tax Rate Continuing Operations</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_DeferredIncomeTaxExpenseBenefitRelatedToRemeasurementDueToChangeInTaxStatus_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Tax benefit from the remeasurement of deferred taxes due to change in effective tax rate</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_DeferredIncomeTaxExpenseBenefitRelatedToRemeasurementDueToChangeInTaxStatus_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Income Tax Expense Benefit Related To Remeasurement Due To Change In Tax Status</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:type="locator" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">U.S. corporate tax rate</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxAssetsValuationAllowance" xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsValuationAllowance" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DeferredTaxAssetsValuationAllowance_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred tax assets valuation allowance</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxAssetsValuationAllowance" xlink:to="us-gaap_DeferredTaxAssetsValuationAllowance_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DeferredTaxAssetsValuationAllowance_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Tax Assets Valuation Allowance</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilityForUncertainTaxPositionsCurrent" xlink:type="locator" xlink:label="us-gaap_LiabilityForUncertainTaxPositionsCurrent" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LiabilityForUncertainTaxPositionsCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Liability for income taxes associated with uncertain tax positions</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilityForUncertainTaxPositionsCurrent" xlink:to="us-gaap_LiabilityForUncertainTaxPositionsCurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LiabilityForUncertainTaxPositionsCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Liability For Uncertain Tax Positions Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DecreaseInUnrecognizedTaxBenefitsIsReasonablyPossible" xlink:type="locator" xlink:label="us-gaap_DecreaseInUnrecognizedTaxBenefitsIsReasonablyPossible" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DecreaseInUnrecognizedTaxBenefitsIsReasonablyPossible_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Decrease in uncertain tax positions during the next twelve months</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DecreaseInUnrecognizedTaxBenefitsIsReasonablyPossible" xlink:to="us-gaap_DecreaseInUnrecognizedTaxBenefitsIsReasonablyPossible_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DecreaseInUnrecognizedTaxBenefitsIsReasonablyPossible_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Decrease In Unrecognized Tax Benefits Is Reasonably Possible</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_LossContingencyNumberOfClaims" xlink:type="locator" xlink:label="psn_LossContingencyNumberOfClaims" />
    <link:label xml:lang="en-US" xlink:label="psn_LossContingencyNumberOfClaims_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Loss contingency, number of claims.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_LossContingencyNumberOfClaims" xlink:to="psn_LossContingencyNumberOfClaims_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_LegalProceedingsLineItems" xlink:type="locator" xlink:label="psn_LegalProceedingsLineItems" />
    <link:label xml:lang="en-US" xlink:label="psn_LegalProceedingsLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Legal Proceedings [Line Items]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_LegalProceedingsLineItems" xlink:to="psn_LegalProceedingsLineItems_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_LegalProceedingsTable" xlink:type="locator" xlink:label="psn_LegalProceedingsTable" />
    <link:label xml:lang="en-US" xlink:label="psn_LegalProceedingsTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Legal Proceedings [Table]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_LegalProceedingsTable" xlink:to="psn_LegalProceedingsTable_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_LegalProceedingsTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Legal Proceedings [Table]</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LegalProceedingsTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Legal Proceedings [Table]</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LegalProceedingsLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Legal Proceedings [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LegalProceedingsLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Legal Proceedings [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LossContingencyNumberOfClaims_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of claims outstanding</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_LossContingencyNumberOfClaims_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Loss Contingency Number Of Claims</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LossContingencyDamagesSoughtValue" xlink:type="locator" xlink:label="us-gaap_LossContingencyDamagesSoughtValue" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LossContingencyDamagesSoughtValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loss contingency damages value</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LossContingencyDamagesSoughtValue" xlink:to="us-gaap_LossContingencyDamagesSoughtValue_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LossContingencyDamagesSoughtValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Loss Contingency Damages Sought Value</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_CommonStockSharesOutstandingIncludingEmployeeStockOwnershipPlanShares" xlink:type="locator" xlink:label="psn_CommonStockSharesOutstandingIncludingEmployeeStockOwnershipPlanShares" />
    <link:label xml:lang="en-US" xlink:label="psn_CommonStockSharesOutstandingIncludingEmployeeStockOwnershipPlanShares_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Common stock shares outstanding including employee stock ownership plan shares.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_CommonStockSharesOutstandingIncludingEmployeeStockOwnershipPlanShares" xlink:to="psn_CommonStockSharesOutstandingIncludingEmployeeStockOwnershipPlanShares_lbl" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfEmployeeStockOwnershipPlanESOPDisclosuresTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfEmployeeStockOwnershipPlanESOPDisclosuresTable" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfEmployeeStockOwnershipPlanESOPDisclosuresTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Employee Stock Ownership Plan E S O P Disclosures [Table]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfEmployeeStockOwnershipPlanESOPDisclosuresTable" xlink:to="us-gaap_ScheduleOfEmployeeStockOwnershipPlanESOPDisclosuresTable_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfEmployeeStockOwnershipPlanESOPDisclosuresTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Employee Stock Ownership Plan E S O P Disclosures [Table]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_DirectCostsOfContractsAndIndirectGeneralAndAdministrativeExpenseMember" xlink:type="locator" xlink:label="psn_DirectCostsOfContractsAndIndirectGeneralAndAdministrativeExpenseMember" />
    <link:label xml:lang="en-US" xlink:label="psn_DirectCostsOfContractsAndIndirectGeneralAndAdministrativeExpenseMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Direct costs of contracts and indirect, general and administrative expense.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_DirectCostsOfContractsAndIndirectGeneralAndAdministrativeExpenseMember" xlink:to="psn_DirectCostsOfContractsAndIndirectGeneralAndAdministrativeExpenseMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_DirectCostsOfContractsAndIndirectGeneralAndAdministrativeExpenseMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Direct Costs of Contracts and Indirect, General and Administrative Expense</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_DirectCostsOfContractsAndIndirectGeneralAndAdministrativeExpenseMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Direct Costs Of Contracts And Indirect General And Administrative Expense [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeStockOwnershipPlanESOPDisclosuresLineItems" xlink:type="locator" xlink:label="us-gaap_EmployeeStockOwnershipPlanESOPDisclosuresLineItems" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_EmployeeStockOwnershipPlanESOPDisclosuresLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_EmployeeStockOwnershipPlanESOPDisclosuresLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Employee Stock Ownership Plan E S O P Disclosures [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDescription" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDescription" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDescription_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Shares fully vested, Description</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDescription" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDescription_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDescription_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Share Based Compensation Arrangement By Share Based Payment Award Description</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Shares fully vested after credited service</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Share Based Compensation Arrangement By Share Based Payment Award Award Vesting Period1</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_CommonStockSharesOutstandingIncludingEmployeeStockOwnershipPlanShares_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock shares outstanding including ESOP</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_CommonStockSharesOutstandingIncludingEmployeeStockOwnershipPlanShares_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock Shares Outstanding Including Employee Stock Ownership Plan Shares</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeStockOwnershipPlanESOPSharesInESOP" xlink:type="locator" xlink:label="us-gaap_EmployeeStockOwnershipPlanESOPSharesInESOP" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_EmployeeStockOwnershipPlanESOPSharesInESOP_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Company&apos;s stock held by ESOP</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeStockOwnershipPlanESOPSharesInESOP" xlink:to="us-gaap_EmployeeStockOwnershipPlanESOPSharesInESOP_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_EmployeeStockOwnershipPlanESOPSharesInESOP_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Employee Stock Ownership Plan E S O P Shares In E S O P</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeStockOwnershipPlanESOPCompensationExpense" xlink:type="locator" xlink:label="us-gaap_EmployeeStockOwnershipPlanESOPCompensationExpense" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_EmployeeStockOwnershipPlanESOPCompensationExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">ESOP contribution expense</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeStockOwnershipPlanESOPCompensationExpense" xlink:to="us-gaap_EmployeeStockOwnershipPlanESOPCompensationExpense_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_EmployeeStockOwnershipPlanESOPCompensationExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Employee Stock Ownership Plan E S O P Compensation Expense</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_EmployeeStockOwnershipPlanESOPDividendsDeclaredPerShare" xlink:type="locator" xlink:label="psn_EmployeeStockOwnershipPlanESOPDividendsDeclaredPerShare" />
    <link:label xml:lang="en-US" xlink:label="psn_EmployeeStockOwnershipPlanESOPDividendsDeclaredPerShare_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Employee stock ownership plan ESOP dividends declared per share.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_EmployeeStockOwnershipPlanESOPDividendsDeclaredPerShare" xlink:to="psn_EmployeeStockOwnershipPlanESOPDividendsDeclaredPerShare_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_EmployeeStockOwnershipPlanESOPDividendsDeclaredToESOP" xlink:type="locator" xlink:label="psn_EmployeeStockOwnershipPlanESOPDividendsDeclaredToESOP" />
    <link:label xml:lang="en-US" xlink:label="psn_EmployeeStockOwnershipPlanESOPDividendsDeclaredToESOP_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Employee stock ownership plan ESOP dividends declared to ESOP.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_EmployeeStockOwnershipPlanESOPDividendsDeclaredToESOP" xlink:to="psn_EmployeeStockOwnershipPlanESOPDividendsDeclaredToESOP_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_EmployeeStockOwnershipPlanESOPDividendsPaymentDate" xlink:type="locator" xlink:label="psn_EmployeeStockOwnershipPlanESOPDividendsPaymentDate" />
    <link:label xml:lang="en-US" xlink:label="psn_EmployeeStockOwnershipPlanESOPDividendsPaymentDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Employee stock ownership plan ESOP dividends payment date.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_EmployeeStockOwnershipPlanESOPDividendsPaymentDate" xlink:to="psn_EmployeeStockOwnershipPlanESOPDividendsPaymentDate_lbl" />
    <link:loc xlink:href="psn-20200630.xsd#psn_EmployeeStockOwnershipPlanESOPDividendDeclaredDate" xlink:type="locator" xlink:label="psn_EmployeeStockOwnershipPlanESOPDividendDeclaredDate" />
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    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_EmployeeStockOwnershipPlanESOPDividendDeclaredDate" xlink:to="psn_EmployeeStockOwnershipPlanESOPDividendDeclaredDate_lbl" />
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    <link:label xml:lang="en-US" xlink:label="us-gaap_TemporaryEquityValueExcludingAdditionalPaidInCapital_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Temporary Equity Value Excluding Additional Paid In Capital</link:label>
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    <link:label xml:lang="en-US" xlink:label="psn_EmployeeStockOwnershipPlanESOPDividendDeclaredDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Employee Stock Ownership Plan E S O P Dividend Declared Date</link:label>
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    <link:label xml:lang="en-US" xlink:label="psn_EmployeeStockOwnershipPlanESOPDividendsDeclaredPerShare_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Employee Stock Ownership Plan E S O P Dividends Declared Per Share</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_EmployeeStockOwnershipPlanESOPDividendsDeclaredToESOP_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">ESOP dividends declared amount</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_EmployeeStockOwnershipPlanESOPDividendsDeclaredToESOP_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Employee Stock Ownership Plan E S O P Dividends Declared To E S O P</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_EmployeeStockOwnershipPlanESOPDividendsPaymentDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">ESOP dividends payment date</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_EmployeeStockOwnershipPlanESOPDividendsPaymentDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Employee Stock Ownership Plan E S O P Dividends Payment Date</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DividendsPayableDateDeclaredDayMonthAndYear" xlink:type="locator" xlink:label="us-gaap_DividendsPayableDateDeclaredDayMonthAndYear" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DividendsPayableDateDeclaredDayMonthAndYear_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Dividends declared date</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_DividendsPayableDateDeclaredDayMonthAndYear_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Dividends Payable Date Declared Day Month And Year</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DividendsPayableDateOfRecordDayMonthAndYear" xlink:type="locator" xlink:label="us-gaap_DividendsPayableDateOfRecordDayMonthAndYear" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DividendsPayableDateOfRecordDayMonthAndYear_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Dividends record date</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DividendsPayableDateOfRecordDayMonthAndYear" xlink:to="us-gaap_DividendsPayableDateOfRecordDayMonthAndYear_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DividendsPayableDateOfRecordDayMonthAndYear_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Dividends Payable Date Of Record Day Month And Year</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DividendsCommonStock" xlink:type="locator" xlink:label="us-gaap_DividendsCommonStock" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DividendsCommonStock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Dividends declared amount</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DividendsCommonStock" xlink:to="us-gaap_DividendsCommonStock_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_DividendsCommonStock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Dividends Common Stock</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfEquityMethodInvestmentsTable" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfEquityMethodInvestmentsTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Equity Method Investments [Table]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:to="us-gaap_ScheduleOfEquityMethodInvestmentsTable_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfEquityMethodInvestmentsTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Equity Method Investments [Table]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:type="locator" xlink:label="srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" />
    <link:label xml:lang="en-US" xlink:label="srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Investment, Name</link:label>
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    <link:label xml:lang="en-US" xlink:label="srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Equity Method Investment Equity Method Investee Name [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_EquityMethodInvesteeNameDomain" xlink:type="locator" xlink:label="srt_EquityMethodInvesteeNameDomain" />
    <link:label xml:lang="en-US" xlink:label="srt_EquityMethodInvesteeNameDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Investment, Name</link:label>
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    <link:label xml:lang="en-US" xlink:label="srt_EquityMethodInvesteeNameDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Equity Method Investee Name [Domain]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_UnconsolidatedJointVenturesMember" xlink:type="locator" xlink:label="psn_UnconsolidatedJointVenturesMember" />
    <link:label xml:lang="en-US" xlink:label="psn_UnconsolidatedJointVenturesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Unconsolidated joint ventures.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_UnconsolidatedJointVenturesMember" xlink:to="psn_UnconsolidatedJointVenturesMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_UnconsolidatedJointVenturesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unconsolidated Joint Ventures</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_UnconsolidatedJointVenturesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Unconsolidated Joint Ventures [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:type="locator" xlink:label="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Equity Method Investments [Line Items]</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Equity Method Investments [Line Items]</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_AssetsNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Noncurrent assets</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_AssetsNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Assets Noncurrent</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current liabilities</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_StockholdersEquity_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Total joint venture equity</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_CostOfGoodsAndServicesSold_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Costs</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Net income (loss) attributable to noncontrolling interests</link:label>
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    <link:label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Noncurrent liabilities</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesNoncurrent" xlink:to="us-gaap_LiabilitiesNoncurrent_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities Noncurrent</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_IncomeLossFromEquityMethodInvestments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Equity in earnings of unconsolidated joint ventures</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_DistributionsFromContributionsToEquityMethodInvestment" xlink:type="locator" xlink:label="psn_DistributionsFromContributionsToEquityMethodInvestment" />
    <link:label xml:lang="en-US" xlink:label="psn_DistributionsFromContributionsToEquityMethodInvestment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Distributions from (contributions to) equity method investment.</link:label>
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    <link:loc xlink:href="psn-20200630.xsd#psn_ReimbursableCostIncurred" xlink:type="locator" xlink:label="psn_ReimbursableCostIncurred" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionOtherRevenuesFromTransactionsWithRelatedParty" xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionOtherRevenuesFromTransactionsWithRelatedParty" />
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    <link:label xml:lang="en-US" xlink:label="psn_ReimbursableCostIncurred_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reimbursable cost incurred</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ReimbursableCostIncurred_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Reimbursable Cost Incurred</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:type="locator" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" />
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    <link:label xml:lang="en-US" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Weighted Average Number Of Shares Outstanding Basic</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment" xlink:type="locator" xlink:label="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Dilutive common share equivalents</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment" xlink:to="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Weighted Average Number Diluted Shares Outstanding Adjustment</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:type="locator" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Diluted weighted average number of shares outstanding</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:to="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Weighted Average Number Of Diluted Shares Outstanding</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Segment Reporting Information By Segment [Table]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Segment Reporting Information By Segment [Table]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementGeographicalAxis" xlink:type="locator" xlink:label="srt_StatementGeographicalAxis" />
    <link:label xml:lang="en-US" xlink:label="srt_StatementGeographicalAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Geographical</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_StatementGeographicalAxis" xlink:to="srt_StatementGeographicalAxis_lbl" />
    <link:label xml:lang="en-US" xlink:label="srt_StatementGeographicalAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Statement Geographical [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SegmentGeographicalDomain" xlink:type="locator" xlink:label="srt_SegmentGeographicalDomain" />
    <link:label xml:lang="en-US" xlink:label="srt_SegmentGeographicalDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Geographical</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_SegmentGeographicalDomain" xlink:to="srt_SegmentGeographicalDomain_lbl" />
    <link:label xml:lang="en-US" xlink:label="srt_SegmentGeographicalDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Segment Geographical [Domain]</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/country/2020/country-2020-01-31.xsd#country_US" xlink:type="locator" xlink:label="country_US" />
    <link:label xml:lang="en-US" xlink:label="country_US_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">United States</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="country_US" xlink:to="country_US_lbl" />
    <link:label xml:lang="en-US" xlink:label="country_US_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">UNITED STATES</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:type="locator" xlink:label="us-gaap_SegmentReportingInformationLineItems" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_SegmentReportingInformationLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Segment Reporting Information [Line Items]</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_SegmentReportingInformationLineItems_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_SegmentReportingInformationLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting Information [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NumberOfReportableSegments" xlink:type="locator" xlink:label="us-gaap_NumberOfReportableSegments" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_NumberOfReportableSegments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of reportable segments</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NumberOfReportableSegments" xlink:to="us-gaap_NumberOfReportableSegments_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_NumberOfReportableSegments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Number Of Reportable Segments</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/positiveLabel">Total revenue</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_ReconciliationFromNetIncomeToAdjustedEBITDAAbstract" xlink:type="locator" xlink:label="psn_ReconciliationFromNetIncomeToAdjustedEBITDAAbstract" />
    <link:label xml:lang="en-US" xlink:label="psn_ReconciliationFromNetIncomeToAdjustedEBITDAAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Reconciliation from net income to adjusted EBITDA.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_ReconciliationFromNetIncomeToAdjustedEBITDAAbstract" xlink:to="psn_ReconciliationFromNetIncomeToAdjustedEBITDAAbstract_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_ReconciliationFromNetIncomeToAdjustedEBITDAAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Adjusted EBITDA attributable to Parsons Corporation</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ReconciliationFromNetIncomeToAdjustedEBITDAAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Reconciliation From Net Income To Adjusted E B I T D A [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_AdjustedEBITDAAttributableToParent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Adjusted EBITDA attributable to Parsons Corporation</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_AdjustedEBITDAAttributableToParent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Adjusted E B I T D A Attributable To Parent</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_AdjustedEBITDAAttributableToNoncontrollingInterests_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Adjusted EBITDA attributable to noncontrolling interests</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_AdjustedEBITDAAttributableToNoncontrollingInterests_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Adjusted E B I T D A Attributable To Noncontrolling Interests</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_DepreciationAndAmortization_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Depreciation and amortization</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestIncomeExpenseNet" xlink:type="locator" xlink:label="us-gaap_InterestIncomeExpenseNet" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_InterestIncomeExpenseNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest expense, net</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestIncomeExpenseNet" xlink:to="us-gaap_InterestIncomeExpenseNet_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_InterestIncomeExpenseNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Interest Income Expense Net</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_EquityBasedCompensationIncomeExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Equity-based compensation expense</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_EquityBasedCompensationIncomeExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Equity Based Compensation Income Expense</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_TransactionRelatedCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Transaction-related costs</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_TransactionRelatedCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Transaction Related Costs</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_RestructuringIncomeExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restructuring expense</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_RestructuringIncomeExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring Income Expense</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_OtherReconciliationFromNetIncomeToAdjustedEBITDA_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Other</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_OtherReconciliationFromNetIncomeToAdjustedEBITDA_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Other Reconciliation From Net Income To Adjusted E B I T D A</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net income attributable to noncontrolling interests</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_NorthAmericaMember" xlink:type="locator" xlink:label="srt_NorthAmericaMember" />
    <link:label xml:lang="en-US" xlink:label="srt_NorthAmericaMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">North America</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_NorthAmericaMember" xlink:to="srt_NorthAmericaMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="srt_NorthAmericaMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">North America [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MiddleEastMember" xlink:type="locator" xlink:label="us-gaap_MiddleEastMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_MiddleEastMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Middle East</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MiddleEastMember" xlink:to="us-gaap_MiddleEastMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_MiddleEastMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Middle East [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NonUsMember" xlink:type="locator" xlink:label="us-gaap_NonUsMember" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_NonUsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Rest of World</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NonUsMember" xlink:to="us-gaap_NonUsMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_NonUsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Non Us [Member]</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Property and Equipment, Net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsegmentsAxis" xlink:type="locator" xlink:label="us-gaap_SubsegmentsAxis" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_SubsegmentsAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Subsegments</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SubsegmentsAxis" xlink:to="us-gaap_SubsegmentsAxis_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_SubsegmentsAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Subsegments [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsegmentsDomain" xlink:type="locator" xlink:label="us-gaap_SubsegmentsDomain" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_SubsegmentsDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Subsegments</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SubsegmentsDomain" xlink:to="us-gaap_SubsegmentsDomain_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_SubsegmentsDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Subsegments [Domain]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_SpaceAndGeospatialSolutionsMember" xlink:type="locator" xlink:label="psn_SpaceAndGeospatialSolutionsMember" />
    <link:label xml:lang="en-US" xlink:label="psn_SpaceAndGeospatialSolutionsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Space and Geospatial Solutions.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_SpaceAndGeospatialSolutionsMember" xlink:to="psn_SpaceAndGeospatialSolutionsMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_SpaceAndGeospatialSolutionsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Space &amp; Geospatial Solutions</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_SpaceAndGeospatialSolutionsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Space And Geospatial Solutions [Member]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_CyberAndIntelligenceMember" xlink:type="locator" xlink:label="psn_CyberAndIntelligenceMember" />
    <link:label xml:lang="en-US" xlink:label="psn_CyberAndIntelligenceMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Cyber &amp; Intelligence.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_CyberAndIntelligenceMember" xlink:to="psn_CyberAndIntelligenceMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_CyberAndIntelligenceMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cyber &amp; Intelligence</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_CyberAndIntelligenceMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Cyber And Intelligence [Member]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_EngineeredSystemsMember" xlink:type="locator" xlink:label="psn_EngineeredSystemsMember" />
    <link:label xml:lang="en-US" xlink:label="psn_EngineeredSystemsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Engineered systems.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_EngineeredSystemsMember" xlink:to="psn_EngineeredSystemsMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_EngineeredSystemsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Engineered Systems</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_EngineeredSystemsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Engineered Systems [Member]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_MissileDefenseC5ISRMember" xlink:type="locator" xlink:label="psn_MissileDefenseC5ISRMember" />
    <link:label xml:lang="en-US" xlink:label="psn_MissileDefenseC5ISRMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Missile Defense &amp; C5ISR.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_MissileDefenseC5ISRMember" xlink:to="psn_MissileDefenseC5ISRMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_MissileDefenseC5ISRMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Missile Defense &amp; C5ISR</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_MissileDefenseC5ISRMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Missile Defense C5 I S R [Member]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_ConnectedCommunitiesMember" xlink:type="locator" xlink:label="psn_ConnectedCommunitiesMember" />
    <link:label xml:lang="en-US" xlink:label="psn_ConnectedCommunitiesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Connected Communities.</link:label>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="psn_ConnectedCommunitiesMember" xlink:to="psn_ConnectedCommunitiesMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="psn_ConnectedCommunitiesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Connected Communities</link:label>
    <link:label xml:lang="en-US" xlink:label="psn_ConnectedCommunitiesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Connected Communities [Member]</link:label>
    <link:loc xlink:href="psn-20200630.xsd#psn_MobilitySolutionsMember" xlink:type="locator" xlink:label="psn_MobilitySolutionsMember" />
    <link:label xml:lang="en-US" xlink:label="psn_MobilitySolutionsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Mobility solutions.</link:label>
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