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   ThismemodescribesthemethodsandresultsofEPAsresidualrisktestforthe Y shipbuildingandshiprepairsourcecategory.TheresidualrisktestisconductedbyEPAatthe B beginningoftheresidualruledevelopmentprocess.ItisEPAsintentthatthetestbecompleted + quickly,usuallywithin1to3monthsfromthetimetheprojectstarts.Thepurposeofthe  residualrisktestistodetermine,basedondataalreadyinEPAspossessionandarelatively  simpleandprotective(i.e.,conservative)analysis,whetherthesourcecategorycanbeshownat  theoutsetnottorequirearesidualriskrule.UndertherequirementsoftheCleanAirAct  Amendmentsof1990,EPAwillnotpromulgateadditionalemissionstandardsforasource p categoryifexistingMACTstandardsprovidean amplemarginofsafetyforhumanhealthand Y aresufficienttopreventadverseenvironmentalimpacts(CAAAsection112(f)(2)(A)). B     Theresidualrisktestisnotintendedtobeacomplexorexhaustiveassessment.Itis, \ instead,anaprioriattempttodetermineifwealreadyknowenoughtoeliminatethesource E  categoryasasourceoffurtherconcern.AdeterminationbyEPAnottoremoveasource . ! categoryfromtheresidualriskprocessatthisstageinnowaysuggeststhataresidualriskruleis !" inevitable,onlythatEPAlackssufficientdataatthistimetoforegosucharule. "#   TheresidualrisktestinthiscaseshowedthatEPAdoesnothavesufficientdatato # % removetheshipbuildingsourcecategoryfromconsiderationforaresidualriskrule.EPAwill $s!& thereforedevelopadatagatheringandanalysisplanandobtainmorerefineddata(e.g.,on %\"' processes,emissions,emissioncontrolequipment,costs,etc.)forfacilitiesinthissource &E#( category.Wewillusethesedatatosimultaneouslyrefineourriskanalysisandconsiderpossible v'.$) riskreductionoptions,thecostofthoseoptions,andotherfactors.EPAwilluseallthesedata _(%* whenconsideringaresidualriskrule,andmayatanytimedeterminethataruleisnotnecessary H)&+ (e.g.,becauseoflowrisk,infeasibility,lowbenefittocostratio,etc.). 1*&,   .v+1 xh 84dXXd8   Methods   1.Scope.    Theresidualrisktestfortheshipbuildingandshiprepairsourcecategoryfocusedsolely ~ onhumanhealth,estimatingtheemissionspotentialtocreatechronic(i.e.,70year)cancerand g  noncancerrisksandacute(e.g.,1hour)noncancerrisks.Becausehealthriskcouldnotbe P v eliminatedasaconcern,noassessmentofpotentialimpactstoenvironmentalreceptorswas 9 _ developed.Theanalysisincludedemissionsassociatedwithcoating,cleaning,welding,cutting, " H andblastingoperations.  1  2.SelectionofHAPsandDoseResponseInformation.     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j`'pP."d 333333?3.0E-01d333333?j_3.0E-01_____________________  ԍ̎  LpP/" 333333?3.0E-01 333333?d @1.6E+03d@1.6E+03 j`PpP0" @1.6E+03 D @d DdjMethanol <21d d<! j`'2"d @@4.0E+03d@@j_4.0E+03_____________________  ԍ̎  L3" @@4.0E+03 @@d %A6.9E+05d%A6.9E+05 j`P4" %A6.9E+05 D %Ad DdjMethylchloride <25d d<! j`'6"d V@9.0E+01dV@j_9.0E+01_____________________  ԍ̎  L7" V@9.0E+01 V@d @@1.0E+03d@@1.0E+03 j`P8" @@1.0E+03 D @@d DdjMethylchloroform <2<9d d<! j`'<:"d @@1.0E+03d@@j1.0E+03 K<;" @@1.0E+03 @@d  3A1.3E+06d 3A1.3E+06 j`P<<"  3A1.3E+06 D  3Ad DdjMethylethylketone <2`=d d<! j`'`>"d @@1.0E+03d@@j_1.0E+03_____________________  ԍ̎  L`?" @@1.0E+03 @@d d@1.3E+04dd@1.3E+04 j`P`@" d@1.3E+04 D d@d DdjMethyl_isobutyl_Ԁketone <2Ad d<! j`'B"d T@8.0E+01dT@j_8.0E+01_____________________  ԍ̎  j`LC" T@8.0E+01 T@d dj!#XX %&S@#&S@ %XX F<,D" D d DdFMethylenechloride aWEd M7܉>4.7E-07dM7܉>a_4.7E-07_____________________  ԍ̎  LF" M7܉>4.7E-07 M7܉>d @@1.0E+03d@@_1.0E+03_____________________  ԍ̎  LG" @@1.0E+03 @@d X@1.4E+04dX@1.4E+04 j`PH" X@1.4E+04 D X@d DdjNickelcompounds aWL,Id MP4?3.1E-04dMP4?a3.1E04 Z#  7      KL,J" MP4?3.1E-04 MP4?d ?2.0E-01d?_2.0E-01_____________________  ԍ******  LL,K" ?2.0E-01 ?d @@1.0E+03d@@1.0E+03 j`PL,L" @@1.0E+03 D @@d DdjPhenol <2pMd d<! j`'pN"d i@2.0E+02di@j_2.0E+02_____________________  ԍ̎  LpO" i@2.0E+02 i@d @1.7E+04d@1.7E+04 j`PpP" @1.7E+04 D @d Ddj_Polycyclic_Ԁorganicmatter aW Qd K8 ?5.5E-05dK8 ?a5.5E05| Z#  8      #XX %&S@n#&S@ %XX i_K R" K8 ?5.5E-05 K8 ?d di!#XX %&S@#&S@ %XX E;' S"d dE!#XX %&S@#&S@ %XX F<, T" D d DdF_Tetrachloroethylene_Ԁ aW"Ud >5.9E-06d>a5.9E_Ԅ06#XX %&S@6#&S@ %XX_____________________  ԍ2.7E+02  L"V" >5.9E-06 >d p@2.7E+02dp@2.7E+02 K"W" p@2.7E+02 p@d L A2.4E+05dL A2.4E+05 j`P"X" L A2.4E+05 D L Ad DdjToluene <2\#<Yd d<! j`'\#<Z"d y@4.0E+02dy@j_4.0E+02_____________________  ԍ̎  L\#<[" y@4.0E+02 y@d A3.1E+05dA3.1E+05 j`P\#<\" A3.1E+05 D Ad DdjTrichloroethylene aW$]d >2.0E-06d>a_2.0E-06_____________________  ԍ̎  L$^" >2.0E-06 >d @6.0E+02d@_6.0E+02_____________________  ԍ̎  L$_" @6.0E+02 @d z A5.4E+05dz A5.4E+05 j`P$`" z A5.4E+05 D z Ad Ddj_Xylenes_Ԁ(mixedisomers) <2%ad d<! j`'%b"d z@4.3E+02dz@j_4.3E+02_____________________  ԍ̎  L%c" z@4.3E+02 z@d !A5.6E+05d!A5.6E+05`VT%d" !A5.6E+05 D !Ad `#XX %&S@j# &d Tf T  H T  3.DispersionModelingforChronicExposures. B   WeselectedtheEPAHumanExposureModel(HEM)forthechronicportionofthe  residualrisktest.TheHEMcontains(1)anatmosphericdispersionmodelwithmeteorological  data,and(2)anexposuremodelbasedonU.S.BureauofCensuspopulationdatafor2000atthe   censusblocklevel.     HEMsdispersionmodelisaGaussianmodelbasedontheIndustrialSourceComplex  _ LongTermmodel,ISCLT2,thathasbeensimplifiedtoimprovecomputationalefficiency.  H Necessarysourcerelatedinputsincludemapcoordinatesandheightoftherelease,exitvelocity, s1  stackdiameter,andtemperature.Specifyingthelatitudeandlongitudeofthefacilitycallsthe \  stabilityarray(STAR)summaryfromthenearestmeteorologicalstationforuseinthedispersion E  algorithm.TheSTARdataarestandardclimatologicalsummaries(obtainedfromtheNational .  ClimaticCenter,Asheville,NC)formulatedforuseinEPAmodels.ASTARsummaryisajoint   frequencyofoccurrenceofwindspeed,atmosphericstability,andwinddirection,reflecting5   yearsofdatafor348USsites.     Themodelproducespolarcoordinatereceptorgridpointsconsistingof10downwind y distances(extendingto50km)locatedalongeachof16radials.Thedispersionmodelestimates b concentrationsforeachofthe160receptorlocationsonthisgrid.Tosimulatehumanexposure, K theHEMrelocatestheISCLT2concentrationestimatesfromtheirradialgridtocentroidsof v4 populationcensusblocksbyinterpolation(radiallylogarithmicandazimuthallyarithmetic).The _ estimatedambientconcentrationateachcensusblockcentroidispresumedrepresentativeof H peoplelivinginthatblock. 1   Annualsitespecificemissionsdatawereobtainedfromthe1999NationalEmissions  Inventory(NEI)andthemostrecentavailableToxicsReleaseInventory(TRI).Dataincluded  yearlyemissionratesofHAPsandmapcoordinatesforthetenlargestemitters,intermsoftons  peryear,outof396facilitiesinthesourcecategory(ofwhichapproximately40wereestimated | tobemajorsources).Becausetheemissionsdatawereselfreportedbytheindividualfacilitiesto  e theNEIandTRI,itislikelythatthedatawerecollectedbyavarietyofmethods.Useofdifferent !N methodologiesbydifferentfacilitiesmayhaveresultedininconsistenciesintheemissions y"7 databaseusedfortheresidualrisktest. b#     FacilitycoordinateswereverifiedthrougheithertheDeLormeStreetAtlasormapsat 4%" 4? oO  5  www.topozone.com6oO  7 H.Sitespecificreleaseparameterswerenotavailableforanyfacility,norwas &# informationonactivitiesperformedatthesite.Ingeneral,mostoftheemittedcarcinogenswere ' $ metalsassociatedwithweldingoperations.Therefore,weldingwasconsideredtobethe '!% preferredactivityformodelingpurposes,andthereleaseparameterswereselectedtobest ("& representthisactivity. )#'   Althoughweldingisconsideredanareasource,emissionsforeachfacilityweremodeled +Q%) asapointsourceinordertopermittheuseoftheHEM(whichwasdevelopedprimarilyfor |,:&* majorpointsources).Allemissionswereassumedtooccuratthedrydocknearesttoapopulated e-#'+ area. N. (,  7/(- Q Q Q    Asensitivityanalysiswasperformedtodeterminetheimpactofthestackheightinput z assumption.Heightsof6.15(20'),15.4(50')and24.6(80')meterswereconsidered.Thestack c heightof6.15m,andotherreleaseparametersshownbelow,weredeterminedtobestrepresent L weldingactivitieswithinashipyard,basedoncommentsfromshipyardrepresentatives 5 (summarizedinD.ReevesmemoshowninAppendixA).   Stackheight(meters)0 0 (# (#0h(#(#0h(#h(#0(#(#0p(#(#6.15 vp(#p(# Stackdiameter(meters)0  0h(#(#0h(#h(#0(#(#0p(#(#1.0 _p(#p(# Stackgasexitvelocity(m/sec)0 h 0h(#h(#0(#(#0p(#(#0.1 Hp(#p(# Stackgastemperature(K)0  0h(#(#0h(#h(#0(#(#0p(#(#298 1 p(#p(# Buildingcrosssectionalarea(m2)0 h 0h(#h(#0(#(#0p(#(#100 p(#p(#   MeteorologystabilityclassesusedintheHEMmodelwerebasedonassumedurbanland f  usage(i.e.,significantamountsofcementandasphalt,whichelevatetemperaturesduringtheday O  andcoolmorerapidlyatnight).Thesedefaultmodelinputswilllikelyhaverepresentedsome 8  facilitiesbetterthanothers,sotheaccuracyofmodeloutputsmayvaryamongfacilities. !    TheHEMallowsonlyonedoseresponsevaluetobeinputpermodelingrun.Toreduce y thetotalnumberofnecessarymodelruns,emissionsofeachHAPwereadjustedtorisk b equivalenttonsofasinglereferencesubstance,usingequation(1)forcarcinogensandequation K (2)fornoncarcinogens. 4    `     h    `    ~gO^H84r| h   `.H !@E  ,  ~  (1)     `    sve?/+b|2w: `.@E p as p   (2)   x       `  Where:0 ` CTPYx)XXXXXXXXcb    x)_XXhXXXhXcb    =Carcinogenicequivalenttonsperyear     X` (#` (#    ` NTPYx)XXXXXXXXcb    x)_XXhXXXhXcb    ݀=Noncancerequivalenttonsperyear !A    ` TPYx)XXXXXXXXcb    ix)%_XXhXXXhXcb    ݀=ReportedtonsperyearforHAPi "*    ` UREx)XXXXXXXXcb    ix)_XXhXXXhXcb    ݀=Unitriskestimate(URE)forHAPi #    ` UREx)XXXXXXXXcb    Rx)_XXhXXXhXcb    ݀=UREforthereferencecompound v$    ` RfCx)XXXXXXXXcb    ix)v_XXhXXXhXcb    ݀=Referenceconcentration(RfC)orequivalentvalueforHAPi _%    ` RfCx)XXXXXXXXcb    Rx)_XXhXXXhXcb    ݀=RfCorequivalentvalueforthereferencecompound H&    ForthisanalysisweusedahypotheticalreferencecompoundwithaUREof1&S@ %XX(%g/m3)1#XX %&S@# ("" andanRfCof1&S@ %XX%g/m3#XX %&S@@#.AdjustedemissionratesofeachHAPweresummedseparatelyfor )## carcinogensandnoncarcinogens,reflectingthedefaultassumptionthatrisksareadditiveacross )r$$ chemicalsunlessadequateevidenceindicatesotherwise.Emissionrateadjustmentreducedthe *[%% numberofmodelrunstotwoperfacility(oneeachforcancerandchronicnoncancer). +D&&   Lifetimecancerriskwasestimatedbymultiplyingthemodeledhighestambient -(( concentrationinanycensusblockbytheUREofthereferencecompound.Thehazardquotient y.() (HQ)fornoncancereffectswascalculatedbydividingthehighestambientconcentrationbythe b/)* ~_ ~9 ~  RfCofthereferencecompound.SinceboththeUREandtheRfCwere1,theambient z concentrationsofthecancerandnoncancermodelrunsequaledtheriskandHQ,respectively. c   Becausethisproceduredoesnotsupportseparationofnoncancereffectsbytargetorgan 5 ortoxicmechanism,thecalculatedHQisreallyahazardindex(HI,definesasthesumofHQs   forindividualpollutants).Incaseswhereeffectsofmultiplenoncarcinogenscontroltheoutcome   oftheresidualrisktest,additionaltargetorganspecificmodelrunswouldbeusedtorefinethe  v assessment.  _ 4.DispersionModelingforAcuteExposures.  1    Fortheacuteexposureportionoftheresidualrisktest,weusedtheSCREEN3air }  dispersionmodel.SCREEN3isascreeninglevelgaussiandispersionmodelusedtopredict f  "worst-case"1-hrconcentrationsonthecenterlineoftheplumedownwindfromasource.The O  SCREEN3modelcontainsasetofwindspeedandatmosphericstabilitycombinationsthatare 8  usedtopredictconcentrationsatuserspecifiedlocationsrangingfrom100metersto5000meters !  downwindfromthesource.     Theacuteanalysiswasbasedonthesameannualsitespecificemissionsdataanddefault b releaseparametersusedforthechronicanalysis,andthereforecarriesthesameuncertainties.To K accountfortemporalvariationintheshorttermemissionratesofthefacilities,weadditionally 4 estimatedthatthemaximumemissionrateonanhourlybasiscouldbeasmuchastentimesthe  annualaveragehourlyrate.BecausetheSCREEN3modeldoesnotincorporatetheHEM,the  acuteanalysisdidnotconsiderpopulationdata,facilitycoordinates,oractualfacilityboundaries. i   TheacuteanalysiswasbasedonasingleSCREEN3modelrunusingthemodelsworst ; casemeteorologydefaults,localflatterrain,andanassumedreferenceemissionrateof1g/s. $ SCREEN3calculatestheambientconcentrationperg/sofemissionsforanysubstance,assuming   nodepositionoratmosphericreactions.Forthepurposeofestimatingacuteexposure,we | considereditreasonabletoassumeanindividualcouldspendanhouratthedownwindpointwith e thehighestconcentration(2435&S@ %XX%g/m3#XX %&S@r#Ԁperg/s,at100m).  N   AnnualemissionsratesforeachHAPateachfacilitywereconvertedtomaximumshort "   termemissionratesusingequation(3). # ! ̀hg4$ ` \L `.JEU%WKU%h0 (3)U%# (# (# Where:0 ` ERMax0 ` (#` (#0 (# (#=0h(#(#Maximumemissionrate(g/s)7("%h(#h(#    ` _ERAnnual_0  =0h(#(#Annualemissionrate(tons/y) )#&h(#h(#    ` AvgMax0  =0h(#(#Tenfoldconversionfactortosimulatemaximumshortterm  *$' emissionrate*x%(h(#h(# ThemaximumdownwindconcentrationforeachHAPwascalculatedwithequation(4). /*- Ї   `    hgy4$ ` \(h `.pEzhgzhh p   (4) z Where:0 ` _CMax_0 ` (#` (#0 (# (#=0h(#(#Maximumdownwindconcentration(&S@ %XX%g/m3#XX %&S@#)Ph(#h(#    ` _Cref_0 0 (# (#=0h(#(#HighestdownwindconcentrationfromSCREEN3(2435 9 &S@ %XX%g/m3#XX %&S@) #Ԁperg/s) "h(#h(# TheacuteHQforeachHAPwascalculatedbydividing_CMax_foreachHAPbytheappropriate n  _ARL_. W   ResultsandDiscussion  )    ThecancerriskandchronicandacuteHIestimatesforthemostexposedcensusblocks   foreachfacilityaresummarizedintheTable2.Theestimatesforchronicexposurerepresent j  individualswhoactuallyliveinthemostimpactedareas.Theestimatesforacuteexposureare S  basedonanindividualwhoisassumedtospendonehouratthepointofhighestacute <  concentration. %   ItisimportanttonotethatthesecancerriskandnoncancerHIestimatesareinherently q protective.Thecancerriskestimatesrepresentacombinationof upperbound_UREs_ Z (describedinTable1)andexposureestimatesbasedpartlyonprotectiveassumptionswheredata C wereabsent.Thetruecancerriskisthereforeprobablyless,andnotlikelytobegreater.The , chronicHIestimatesarederivedfromthesameexposureestimatesasthecancerrisks,combined  with_RfCs_Ԁorsimilardoseresponsevalues(Table1)thatarebelievedtobewithoutadverse  effects.ItispossiblethatexposuresaboveRfClevelswouldalsonotcauseadverseeffects. m TheacuteHIestimatesarebasedonaworstcaseexposurescenarioincombinationwithan V exposurelevelthoughttoproduceonlymild,transienteffects(ornoeffects;Table1).This ? protectivemethodologytranslatestocancerriskandHIestimatesthatareunlikelytobeexceeded ( inmostoftheexposedpopulation,andthatwouldlikelydecreasewithmorecompletesourceand  emissionsdata. t Table2.Summaryofresultsoftheresidualrisktestforshipbuildingandshiprepair.  F! *`d!d dd dd rdd rdd m_\n(#(#,,dd ,dd ,dd ,@dd , dd +  :``X%# # d:&S@ %XX Facility M``X8'|#!"``Xd dM#XX %&S@#&S@ %XXCancer |#" Risk M``X8'U$#"``Xd dMChronic |#$ HI#XX %&S@m#&S@ %XX M``X8'U$%"``Xd dMAcute |#& HI M```X8'U$'"``Xd dMRiskDrivers C``4,|#("  ```Xd dC_Avondale_ a``R%H )``d h㈵>2E-05dh㈵>a_2E05_ ``{I%H *" h㈵>2E-05 h㈵>``d @2.0d@2.0 ``yG%H +" @2.0 @``d @6.2d@6.2 b```OG%H ," @6.2 @``d dbCancer!98%Cr %H - _Noncancer_Ԁ!97%Mn &!!. Acute!100%glycolethers 5``&t'!/```d d5BathIron a``R(g#0``d -C6?1E-04d-C6?a_1E04_ ``|I(g#1" -C6?1E-04 -C6?``d  ףp= ?0.72d ףp= ?0.72 ``|H(g#2"  ףp= ?0.72  ףp= ?``d a2U0*3?3E-04da2U0*3?_3E04_ d```QI(g#3" a2U0*3?3E-04 a2U0*3?``d ddCancer!98%Cr (g#4 _Noncancer_Ԁ!80%Mn,14%Cr )@$5 Acute!#XX %&S@9#&S@ %XXNA 5``&*%6```d d5Cascade a``R,&7``d x8 81E-38dx8 8a_1E38_ ``}I,&8" x8 81E-38 x8 8``d Mb@?5E-04dMb@?_5E04_ ``}I,&9" Mb@?5E-04 Mb@?``d ǺF?7E-04dǺF?_7E04_ d```QI,&:" ǺF?7E-04 ǺF?``d ddCancer!NA ,&; _Noncancer_Ԁ!NA ,_'< Acute!#XX %&S@!#&S@ %XXNA 5``&-8(=```d d5ElectricBoat a``R$d``d :0ye>4E-08d:0ye>a_4E08_ ``}I$d" :0ye>4E-08 :0ye>``d >2E-06d>_2E06_ ``}I$d" >2E-06 >``d -C6*?2E-04d-C6*?_2E04_ d```QI$d" -C6*?2E-04 -C6*?``d ddCancer!NA $d  _Noncancer_Ԁ!NA = Acute!#XX %&S@b#&S@ %XXNA 5``& ```d d5_Ingalls_ a``RC ``d iUMu>3E-05diUMu>a_3E05_ ``|IC  " iUMu>3E-05 iUMu>``d zG?0.21dzG?0.21 ``zHC  " zG?0.21 zG?``d ?1.1d?1.1 b```OGC  " ?1.1 ?``d dbCancer!96%Cr C   _Noncancer_Ԁ!74%Mn,12%Cr,10%  \  Ni  5 Acute!#XX %&S@"#&S@ %XX80%methylchloride,14%   ethyleneglycol 5``&```d d5_Jeffboat_ a``RT``d iUMu?6E-05diUMu?a_6E05_ ``zIT" iUMu?6E-05 iUMu?``d  &@11d&@_11_ ``yFT"  &@11 &@``d (\?0.17d(\?0.17 c```PHT" (\?0.17 (\?``d dcCancer!97%Cr T _Noncancer_Ԁ!99%Mn -  Acute!NA#XX %&S@%#&S@ %XX 5``& ```d d5_Nassco_ a``R3s ``d h㈵>1E-05dh㈵>a_1E05_ ``|I3s " h㈵>1E-05 h㈵>``d Gz?0.47dGz?0.47 ``|H3s " Gz?0.47 Gz?``d Q?7E-02dQ?_7E02_ d```QI3s " Q?7E-02 Q?``d ddCancer!96%Cr 3s  _Noncancer_Ԁ!96%Mn  L  Acute!#XX %&S@x)#&S@ %XXNA 5``&% ```d d5Newport a``RR``d h㈵>2E-05dh㈵>a_2E05_ ``|IR " h㈵>2E-05 h㈵>``d RQ?0.76dRQ?_0.76_ ``{HR!" RQ?0.76 RQ?``d (\?0.17d(\?_0.17_ c```PHR"" (\?0.17 (\?``d dcCancer!75%Cr R# _Noncancer_Ԁ!91%Mn,7%Ni#XX %&S@,#&S@ %XX +k$ Acute!#XX %&S@/#&S@ %XXNA 5``&D%```d d5Norfolk a``Rq&``d & .1>4E-09d& .1>a_4E09_ ``}Iq'" & .1>4E-09 & .1>``d ~jth?3E-03d~jth?_3E03 ``}Iq(" ~jth?3E-03 ~jth?``d Mb`?2E-03dMb`?2E03_ d```QIq)" Mb`?2E-03 Mb`?``d ddCancer!NA q* _Noncancer_Ԁ!NA J+ Acute!#XX %&S@E0#&S@ %XXNA 7```&#c,```d d7_Norshipco_ c```R-```d ǺF?7E-04dǺF?c_7E04_ ```|I." ǺF?7E-04 ǺF?```d zG?0.59dzG?0.59 ```|H/" zG?0.59 zG?```d Q?3E-02dQ?_3E02_ d````QI0" Q?3E-02 Q?```d ddCancer!100%Cr 1 _Noncancer_Ԁ!99%Cr i2 Acute!#XX %&S@e3#&S@ %XXNA.$"B3 ````d .#XX %&S@6#  Cancerriskestimatesweredominatedbychromium;_noncancer_ԀHIestimateswere 4 t4 dominatedbymanganeseforchronicexposure,andglycolethersforacuteexposure. !]5   Baseduponourbestscientificjudgmentwebelievethatacuteexposuresaregenerallynot "/7 ofconcernfortheshipbuildingsourcecategory.Afterconsideringavailableinformationforeach #8 ofthesepollutants,includingtheadditionaluncertaintiesinvolvedinestimatingacuterisksusing $9 _ARLs_Ԁ(i.e.,valuesobtainedfromdoseresponseassessmentsdevelopedbydifferentagenciesfor %: differentpurposes,asperthefootnotetoTable1),wehaveconcludedthatinthepresentcasethe &; hazardforreportedemissionswouldnotbeofpotentialconcern,exceptforthoseofglycol |'< ethers,methylenechloride,andethyleneglycol. e( =   Asdiscussedintheintroduction,thisanalysisisnotexhaustiveandisnotintendedtobe. 7*w"? Wehaveused(1)thebestemissionsdatacurrentlyavailabletous,(2)reasonabledispersion  +`#@ models,and(3)exposurelocationswherereceptorpopulationscurrentlyresideorcouldbe  ,I$A presenttoreceiveacuteexposures.However,weappliedseveralprotectiveassumptionswhere ,2%B datawereabsent,particularlyregardingreleaselocationsandchromium_speciation_.Onbalance, -&C usingourscientificjudgmentandriskassessmentexperience,webelievetheresultsare .'D  /'E protective,meaningthepredictedriskestimatesarelikelyhigherthanwouldbeexpectedto z actuallyoccurintheexposedpopulation. c  ConclusionsandRecommendations  5   Becausetheseestimatessuggestthatatleastsomefacilitiesmayposecancerrisksgreater   thanoneinonemillionandnoncancerhazardindexesgreaterthan0.2,wecannotrecommend  v eliminatingtheshipbuildingandshiprepairsourcecategoryfromconsiderationforaresidual  _ riskrule.WerecommendinsteadthatEPApursuecollectingadditionaldatatoinformthe  H developmentofapossibleresidualriskruleforthissourcecategory.Inparticular,basedonthe  1  resultsofourcurrentassessment,werecommendthatadditionaldatagatheringeffortsconsider   thefollowing: }   KBCDEFGHIJ(Ay3@"B3"  B3zB2A3  0    Moreaccurateannualemissionsratesforchromium,manganese,glycolethers,methyl O  chloride,andethyleneglycol;B3zBB݌8 (#(# Ќ  "B3"  B3C2A3  0    Informationontheratioofhexavalentchromiumtototalchromiumemitted;B3CC݌! (#(# Ќ  "B3"  B3D2A3  0    Informationonthespecificglycolethercompoundsused;B3DD݌ (#(# Ќ  "B3"  B3E2A3  0    Sitespecificreleaselocations;B3EE݌y(#(# Ќ  "B3"  B3zF2A3  0    Sitespecificstackparameters;B3zFF݌b(#(# Ќ  "B3"  B3OG2A3  0    Maximumhourlyemissionratesforglycolethers,methylchloride,andethyleneglycol.B3OG|G݌K(#(# Ќ   @(#3yKBCDEFGHIJA  DocumentationofinputdatausedintheresidualrisktestisincludedinAppendixC  (attached),anExcelspreadsheetwiththefollowingpages:  0   Data0(#(#0` (#(#0 ` (#` (#0 (# (#Rough1999NTI/NEIdataprovidedR(#(# 0   Datasort `    DatasortedbyHAP;(#(# 0   Totalemissions0 (#(#0 (# (#Emissionrateandtoxicity-equivalentscalculationsandvaluesfor $ cancerandnoncancer (#(# 0   Totalemissionssummary  EmissionratesusedinHEM|(#(# 0   HEMcancerinputs   InputdatausedforthecancerRRteste(#(# 0   HEMnoncancerinputs  InputdatausedforthenoncancerRRtest N(#(# Acuteinputsandresults0  EmissionratesusedinSCREEN3,acuteHIestimates!7(#(# $   Attachments # ! AppendixA0 ` 0 ` (#` (#0 (# (#EmissionDataprovidedbyCoating&ConsumerProductsGroupl$"(#(# AppendixB0 ` 0 ` (#` (#0 (# (#MemofromDaveReeves(EPAcontractor)toMohamed U%# Serageldin,conveying1999TRIandNTIdata,withaddendumby >& $ FrankThornwithrevisionsfortheNewportNewsShipyard''!%(#(# AppendixC0 ` 0 ` (#` (#0 (# (#InputDataCalculations("&(#(# AppendixD0 ` 0 ` (#` (#0 (# (#HEMCancerOutput(#'(#(# AppendixE0 ` 0 ` (#` (#0 (# (#HEMChronicNoncancerOutput)h$((#(#