OverviewoftheFinalTCEWorkplanRiskAssessmentTala R. Henry, Ph.D.Director, Risk Assessment DivisionOffice of Pollution Prevention and ToxicsTrichloroethylene(TCE)CASRN79‐01‐6July 29, 2014MainRiskConclusionsWorkersandoccupationalbystandersatsmallcommercialdegreasingfacilitiesanddrycleaningfacilitiesUseTCE‐baseddegreasersandspottingagents,respectivelyPotentialcancerriskconcernsandshort‐termandlong‐termnon‐cancerrisksConsumersandresidentialbystandersUseofTCE‐containingdegreasersandspray‐appliedprotectivecoatingsPotentialshort‐termnon‐cancerrisksOffice of Pollution Prevention and Toxics2OPPT’sBasisforSelectingTCEforRiskEvaluationTCE’shumanhealthhazards–Humancarcinogen,non‐cancereffectsHighexposurepotential–ProducedandimportedintotheU.S.inlargequantities(>250millionpounds/yr)–ToxicReleaseInventory(TRI)database‐TCEpredominantlyreleasedtoair–Inhalationispredominantexposurepathway(highvolatility)Office of Pollution Prevention and Toxics3IndustrialUses (98.3%) ConsumerUses (1.7%)•83.6%‐intermediateformanufacturingofrefrigerant•14.7%‐solventformetalsdegreasing•Automotivedegreasing products•Arts/crafts/homefixativeorcleaner•Homeofficetoneraid•HomemirroredgesealantSource:Glauser andFunda,2012aFootnotes: (a) This source material includes data or information derived from IHS Products provided to the U.S. EPA. IHSproducts have been provided to the U.S. EPAfor its internal use and in the contextof a license agreement. By receiving andaccessing this material, you agree that IHS is not liable to youor any third party for your use of and/or reliance on the IHSdataand information contained in this document,and any such use shall be at your own risk.ScopeoftheAssessmentFocusonthehumanhealthinhalationhazards(i.e.,cancerandnon‐cancer)forthefollowinguses:─Commercialuseasasolventdegreaser─Commercialuseasaspottingagentindrycleaning─Consumeruseasasolventdegreaser─Consumeruseasaclearprotectivecoatingsprayinarts/craftsEnvironmentalriskswerenotevaluatedintheriskassessmentduetominimalconcernsforecologicalhazardsOffice of Pollution Prevention and Toxics4Populations,ExposureScenariosandHeathEffectsofConcernOffice of Pollution Prevention and Toxics6UseScenario ExposureDurationPopulationofInterestPointsofDeparture(POD)Small commercialdegreaser Chronicexposure(2hrsper8‐hrworkday,5days/week)Adult workers(>16yrs)2•Rangeofhazardvaluesforchronic non‐cancerinhalationeffects(liver,kidney,nervoussystem,immunesystem,reproductivesystem,developmentaleffects)asevaluatedbythe2011TCEIRISassessment.•CancereffectsusingIRISinhalationunitriskBystander tosmallcommercialdegreaserChronic exposure1Adult workers(>16yrs)2Worker atdrycleaningfacility Chronicexposure(8‐hrworkday,5days/week)Adult workers(>16yrs)2Occupational bystanderindrycleaningfacilityChronic exposure1Adult workers(>16yrs)2Hobbyist‐degreaseruse Acuteexposure(1 hrperevent,2eventspermonth)Adultconsumers2>16yrsold)•Hazardvalueforfetalcardiacmalformations(Johnson studies),asevaluatedbythe2011TCEIRISassessmentBystandertohobbyist‐degreaser useAcuteexposure1Individualsofallages3Hobbyist‐clear protectingcoatingsprayAcuteexposure(0.5hr perevent,oneeventperweek)Adultconsumers2(>16yrsold)Bystandertohobbyist‐clearprotectingcoatingsprayAcuteexposure1Individualsofallages3Footnote:(1)Individualisinthesamebuilding,butnodirectexposure; (2)Womenofchildbearingageincludingpregnantwomenareincludedintheadultworkerandconsumerpopulation;(3)bystandersofallagesneartheexposuresource(e.g.,children).OccupationalExposureAssessment:DegreasingOffice of Pollution Prevention and Toxics7OccupationalTCEInhalationExposures:SmallCommercialDegreaser/BystanderOffice of Pollution Prevention and Toxics8PopulationExposedWorkplaceExposureConcentrations(24‐hrTWA3inppm)AcuteChronicNon‐cancer CancerWithLEV NoLEV WithLEV NoLEV WithLEV NoLEVWorkers10.1to7 1to66 0.07to5 0.7to47 0.04to3 0.4to27Occupationalbystanders20.01to6 0.1to57 0.01to4 0.1to41 0.005to2 0.05to231Workersaredirectlyinvolvedwithdegreasingoperations.2OccupationalbystandershavethepotentialtobeexposedtoTCEbuttheyarenotdirectlyinvolvedwithdegreasingoperations3TWA=Timeweightedaverage4LEV=localexhaustventilationTypeofFacilityPotentialWorkplaceTCEInhalationExposures(8‐hrTWA)Near‐Field Far‐FieldLEV(ppm)NoLEV(ppm)NumberofWorkersLEV(ppm)NoLEV(ppm)NumberofWorkersSmallcommercialdegreasingfacility0.3to20 3to197 8,895 0.04to17 0.4to172 21,3482011IRISAssessmentComprehensivereviewofhazard/dose‐responsestudiesofTCEandTCEmetabolitesin2011IRISassessment–Organizationoftoxicityreviewbytissue/system–Multiplelinesofevidencesupportingmajorhazard/dose‐responseconclusions(humanepidemiologicdata,animaltoxdata,mechanisticdata,PBPKmodeling,meta‐analysisofcancerepidemiology,BMDmodeling,uncertainty/variabilityanalyses)TCEisreadilyabsorbed/distributedviaoral,dermalandinhalationpathways(metabolismoccursandplaysaroleinhazard)–Crossestheplacentaandcanbetransferredviabreastmilk–Isconsideredahumancarcinogen(IARC,NTP,EPA)–Non‐cancereffectsinclude:neurotoxicity,immuneeffects,liver/kidney,malereproductive,developingfetus(mostsensitiveendpoint)Office of Pollution Prevention and Toxics13OPPTApproachtoHazard/Dose‐ResponseAssessment:Non‐CancerandCancerEffectsNon‐cancer:oralandinhalationstudiesdeemedsuitablebythe2011IRISDifferenthealthendpointsusedtoevaluateacuteorchronicexposurePBPKmodelusedtoderivedifferenthumanequivalentconcentrations(HECs)HECat50th,95thand99thpercentilescalculated─HEC99isprotectiveforasensitiveindividualandpreferredinthisassessmentoverotherpercentilesUsedsameendpoint/study‐specificUFsappliedtoPBPK‐derivedHECsinthe2011TCEIRISassessmentRiskmetric=marginofexposure(MOE)=HumanEquivalentConcentration99÷ HumanExposureInterpretationofpotentialriskbasedonbenchmarkMOE(10)Cancer:Usedtheinhalationunitrisk(IUR)derivedinthe2011IRISassessmentfortheworkerscenario(chronicexposure)Targetsites:kidneycancer,non‐Hodgkin’slymphoma,andlivercancerIUR=410‐6perμg/m3(210‐2perppm)Risk=HumanExposurexIUROffice of Pollution Prevention and Toxics14RiskCharacterization:CancerSmallCommercialDegreasersandBystandersOffice of Pollution Prevention and Toxics190.1 1 10 100 1000 10000 100000 1000000Degreaser+LEV‐‐TypicalExposureDegreaserNoLEV‐‐TypicalExposureDegreaser+LEV‐‐WorstCaseDegreaserNoLEV‐‐WorstCaseBystander+LEV‐‐TypicalExposureBystanderNoLEV‐‐TypicalExposureBystander+LEV‐‐WorstCaseBystanderNoLEV‐‐WorstCaseDegreaser+LEV‐‐TypicalExposureDegreaserNoLEV‐‐TypicalExposureDegreaser+LEV‐‐WorstCaseDegreaserNoLEV‐‐WorstCaseBystander+LEV‐‐TypicalExposureBystanderNoLEV‐‐TypicalExposureBystander+LEV‐‐WorstCaseBystanderNoLEV‐‐WorstCaseNumberofHumanCancerCasesPerMillion800800050000500000100100050000500000NumberofHumanCancerCasesPerMillion1x10‐41x10‐51x10‐6RiskCharacterization:ChronicNon‐CancerRisksforOccupationalExposuresOffice of Pollution Prevention and ToxicsPotential chronic non-cancer risks for a range of human health effects in bothoccupational degreaser and spot cleaning exposure scenarios (i.e., MOEs werebelow the benchmark MOE).Greatest concern was for developmental effects (i.e., fetal cardiac defects),followed by kidney effects and then immunotoxicity, with an overall higher chronicrisk for the degreaser exposure scenarios. In general, this concern wasirrespective of the type of exposure (typical vs worst case) and the availability ofroom ventilation (LEV vs no LEV).Potential chronic risks for reproductive effects and neurotoxicity for degreaserworker exposure scenarios and most of the degreaser bystander exposurescenarios. However, the risk concerns for these effects were reported for fewerspot cleaning worker/bystander scenarios and generally attributed to exposureconditions without room ventilation.Potential chronic risks for liver effects although the risks were less prominent thanthose reported for other health effects. These risks were found only in thedegreaser worker/bystander exposure worst case scenarios and the spotcleaning worker/bystander worst case scenarios with no LEV.RiskCharacterization:AcuteNon‐CancerRisksforOccupationalandConsumerExposuresOffice of Pollution Prevention and ToxicsPotential acute non-cancer risks for developmental effects (i.e., cardiacdefects) for most occupational and residential exposure scenarios (i.e.,MOEs were below the benchmark MOE of 10).Degreaser exposure scenarios showed greater acute risks fordevelopmental effects than those reported for the spot cleaning exposurescenarios.AcknowledgementsOffice of Pollution Prevention and Toxics25Authors and ContributorsMarcus Aguilar David LynchKay Austin Nhan NguyenStanley Barone Nicholas Nairn-BirchIris Camacho Laura NielsenRehan Choudhary Justin RobertsLynn Delpire (retired) Louis ScaranoCathy Fehrenbacher Yvette Selby-MohamaduKathy Hart Todd StedefordDavid TobiasContract SupportPortions of the document weredeveloped with support fromERG and Syracuse Research Corporation.Special thanks to Joe Cobleand his OSHA staff for sharingTCE monitoring data for degreasing facilities.