November 7, 20051Health Effects Information Used In Cancer and Noncancer Risk CharacterizationFor the 1999 National-Scale AssessmentIntroductionHazard identification and dose-response assessmentinformation for the 1999 national-scale assessmentwas obtained from varioussources and prioritized according to (1) conceptualconsistency with EPA risk assessment guidelines and (2) level of reviewreceived. The prioritization process was aimed atincorporating into our assessment the best available science with respect to doseresponse information. The following sources were used.US Environmental Protection Agency (EPA)EPA has developed dose-response assessments for chronic exposure to many of the pollutants in this study. These assessmentstypically specify a reference concentration, or RfC(to protect against effects other than cancer) and/or a unit risk estimate, or URE(to estimate the probability of contracting cancer). The RfC is an estimate, with uncertainty spanning perhaps an order ofmagnitude, of an inhalation exposure to the human population (including sensitive subgroups) that is likely to be withoutappreciable risks of deleterious effects during a lifetime. The URE is the upper-bound excess cancerrisk estimated to result from alifetime of continuous exposure to an agent at a concentration of 1 μg/m3in air. In assessing a substance’s carcinogenic potential,EPA evaluates various types of toxicological data and develops a weight-of-evidence (WOE) determination. Older WOEassessments use an alphanumeric categorization (recommended by EPA’s 1986 guidelines for carcinogen risk assessment);assessments developed since 2002 characterize the WOE with a paragraph of descriptive text (recommended by the current draftrevisions to the 1986 guidelines).EPA disseminates dose-response assessment information in several forms, depending on the level of internal review. EPApublishes dose-response assessments that have achieved full intra-agency consensus on its Integrated Risk Information System(IRIS), which is regularly updated and available on-line athttp://www.epa.gov/iris. All IRIS assessments since 1996 have alsoundergone external scientific peer review.November 7, 20052Agency for Toxic Substances and Disease Registry (ATSDR)ATSDR, which is part of the US Department of Healthand Human Services, develops and publishes MinimalRisk Levels (MRLs)for many toxic substances. The MRL is defined as an estimate of daily human exposure to a substance that is likely to be withoutan appreciable risk of adverse effects (other thancancer) over a specified duration of exposure. MRLs can be derived for acute,intermediate, and chronic duration exposures by theinhalation and oral routes. ATSDR describes MRLsas media-specificconcentrations to be used by health assessors to select environmental contaminants for further evaluation. MRLs are presentedwith only 1 significant figure and are considered concentrations below which contaminants are unlikelyto pose a health threat.Concentrations above an MRL do not necessarily represent a threat, and MRLs are therefore not intendedfor use as predictors ofadverse health effects or for setting cleanup levels.Inhalation MRLs were used in the noncancer portionof this assessment when IRIS RfCs were not available because their concept,definition, and derivation are philosophically consistent (though not identical) with the basis for EPA’s RfCs. ATSDR MRLs arereviewed by an expert panel of external peers and also by an interagency workgroup that includes EPA.MRLs are published inpollutant-specific toxicological profile documents,and also in a table of “comparison values” that ATSDR regularly updates anddistributes (available on-line athttp://www.atsdr.cdc.gov/mrls.html).California Office of Environmental Health Hazard Assessment (OEHHA)The California OEHHA has developed dose-response assessments for many substances, based both on carcinogenicity and healtheffects other than cancer. The process for developing these assessments is similar to that used by theEPA to develop IRIS valuesand incorporates significant external scientific peer review. The non-cancer information includes available inhalation health riskguidance values expressed as chronic inhalation reference exposure levels (RELs). OEHHA defines the REL as a concentrationlevel at (or below) which no health effects are anticipated, a concept that is substantially similar to EPA’s non-cancer doseresponse assessment perspective. This assessment uses chronic RELs in the same way as RfCs when no IRIS or ATSDR valuesexist.OEHHA’s quantitative dose-response information on carcinogenicity by inhalation exposure is expressedin terms of the URE,defined similarly to EPA’s URE. This assessment uses specific OEHHA UREs in the same way as EPA’s when no IRIS or valuesexist. OEHHA’s dose response information for carcinogens and noncarcinogens is available on-line athttp://www.oehha.ca.gov/air/hot_spots/index.html.November 7, 20053US EPA Health Effects Assessment Tables (HEAST)HEAST is a comprehensive listing consisting almostentirely of provisional UREs, RfCs, and other riskassessment information forchemicals of interest. Although the assessments summarized in HEAST have undergone review and have the concurrence ofindividual EPA program offices, and each is supported by an agency reference, they have not had enoughreview to be recognizedas high-quality, EPA-wide consensus information. Because of these limitations, and the fact that HEAST has not been updatedsince 1997 and exists only in hard copy (PB97-921199), this assessment uses HEAST information only when no values from theother sources described above are available.International Agency for Research on Cancer (IARC)The IARC, a branch of the World Health Organization, coordinates and conducts research on the causes of human cancer anddevelops scientific strategies for cancer control.The IARC sponsors both epidemiological and laboratory research, anddisseminates scientific information through meetings, publications, courses and fellowships.As part of its mission, the IARC assembles evidencethat substances cause cancer in humans and issuesjudgments on the strengthof evidence. IARC’s “degrees of evidence” categories are Group 1 (carcinogenic in humans), Group 2A (probably carcinogenic),Group 2B (possibly carcinogenic), Group 3 (not classifiable), and Group 4 (probably not carcinogenic).The categorization schememay be applied to either single chemicals or mixtures. The IARC does not develop quantitative dose-response indices such asUREs, however.IARC’s degrees of evidence for substances are included as supporting information for this assessment as a backup to EPA’s WOEdeterminations, which do not cover all substances and in some cases may be out-of-date. The list of IARC evaluations to date isavailable athttp://monographs.iarc.fr/monoeval/grlist.html.Prioritization of Data SourcesSome substances have been assessed for dose-response by more than one of the agencies used as sourcesfor this analysis. Becausedifferent scientists developed these assessments atdifferent times for purposes that were similar butnot identical, it is inevitableNovember 7, 20054that the results are not totally consistent. In some cases interagency differences were substantial,especially among assessmentsdone many years apart. To resolve interagency discrepancies for this analysis, EPA applied a consistent priority scheme to theuniverse of dose-response information.Externally peer-reviewed assessments under development for the IRIS process were given first priority.These assessments reflectthe most recent available toxicity information anddata analysis, and were used in some cases to supersede existing values on IRIS.Where externally peer reviewed IRIS draft assessments were not available, the next preferred source was EPA’s IRIS database.For substances lacking IRIS assessments, ATSDR MRLs(available only for noncancer effects) received next preference, followedby OEHHA RELs and UREs.Adjustments to Dose-Response InformationFollowing the prioritization of dose-response information, EPA made the following adjustments based onprofessional judgment:•Oral carcinogens lacking inhalation assessments.For 13 carcinogenic substances, (benzotrichloride, captan, DDE,dichlorvos, 3,3'-dimethoxy benzidine, 3,3'-dimethylbenzidine, 1,4-dioxane, ethyl acrylate, isophorone,pentachloronitrobenzene, propylene dichloride, quinoline, and trifluralin) that currently lack inhalation assessments from thesources described above, oral carcinogenic potencyestimates were converted to inhalation UREs. The conversion from oralrisk (per mg/kg/d oral intake) to inhalation risk (perμg/m3inhaled) was based on EPA’s standard assumptions of a 70-kgbody mass and 20 m3/d inhalation rate, as follows:Where: URE = Unit risk estimate for inhalation (risk perμg/m3)CPS = Carcinogenic potency slope for ingestion (risk per mg oral intake per kg body mass per day)EPA understands that conversion of oral dose-response information to inhalation exposure is a problematic risk assessmentpractice. However, the alternative to this would have been to omit these substances from quantitativeinhalation riskestimates altogether, thereby making ade factoassumption of zero carcinogenic potency. For thepurposes of the national-( )×××⋅=−−gmgdmkgdkgmgCPSmgURE 

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μ10001207013113November 7, 20055scale assessment, EPA prefers to use the approach described above to screen these carcinogens for their potentialcontributions to risk. If a substance is determined to be a potentially important contributor to risk, it will be prioritized forfurther dose-response development through EPA’s IRIS process.•Hexavalent chromium compounds. The IRIS RfC for particulate hexavalent chromiumwas used in preference to the RfCfor chromic acid mists and dissolved aerosols.•Formaldehyde. EPA no longer considers the formaldehyde URE reported in IRIS, which is based on a 1987 study, torepresent the best available science in the peer-reviewed literature. Since that time, significant newdata and analyses havebecome available. Accordingly, the 1999 risk estimates for formaldehyde are based on a dose-responsevalue developed bythe CIIT Centers for Health Research (formerly theChemical Industry Institute of Toxicology) and published in 1999. Thisassessment incorporates mechanistic and dosimetricinformation on formaldehyde that had been accumulated over the pastdecade, and developed a URE using approaches that are consistent with EPA's guidelines for carcinogenic risk assessment.EPA had judged that this CIIT modeling effort currently represents the best application of available mechanistic anddosimetric science on the dose-response for portalof entry cancers due to formaldehyde exposures. EPA is currentlyreviewing the CIIT analysis and other recent information, including recently published epidemiologicalstudies, in ourreassessment of our formaldehyde unit risk estimate(URE).•Glycol ethers. Most of the emission inventory information for the glycol ether category reports only the total mass for theentire group without distinguishing between individual glycol ether compounds. These individual compounds, however,vary substantially in toxicity. In order to avoidunderestimating the health hazard associated with glycol ethers, EPA hasprotectively applied the RfC for ethylene glycol methyl ether (the most toxic for which an assessmentexists) to the entiregroup.•Diesel emissions. The 1999 national-scale assessment, as with the1996 assessment, does not include quantitative cancerrisk estimates for diesel emissions because EPA hasjudged that toxicological data are not yet sufficient to develop a URE.However, diesel emissions have been assessed for effects other than cancer, using the 2003 IRIS RfC (which was notavailable for the 1996 assessment).November 7, 20056•Nickel. The IRIS URE for nickel inhalation shown in Table 1 below was derived from evidence of the carcinogenic effectsof insoluble nickel compounds in crystalline form.Soluble nickel species, and insoluble species in amorphous form, do notappear to produce genotoxic effects by the same toxic mode of action as insoluble crystalline nickel.Nickel speciationinformation for some of the largest nickel-emittingsources (including oil combustion, coal combustion, and others)suggests that at least 35% of total nickel emissions may be soluble compounds. The remaining insoluble nickel emissionsare not well-characterized, however. Consistent with this limited information, this analysis has conservatively assumed that65% of emitted nickel is insoluble, and that all insoluble nickel is crystalline. On this basis, the nickel URE (based on nickelsubsulfide, and representative of pure insoluble crystalline nickel) was adjusted to reflect an assumption that 65% of thetotal mass of nickel may be carcinogenic. The ATSDR MRL in Table 2 was not adjusted, however, becausethe noncancereffects of nickel are not thought to be limited tothe crystalline, insoluble form.•2-Nitropropane.The assessment used a URE of 5.6 x 10-6 per ug/m3for 2-nitropropane. This value was derived in 1999by the Health Council of the Netherlands (availableat:http://www.gr.nl/pdf.php?ID=423&p=1), based on induction ofhepatocellular nodules in rats, and is consistent with weight-of-evidence determinations by the U.S. National ToxicologyProgram (“reasonably anticipated to be a human carcinogen”) and the IARC (“possibly carcinogenic to humans”).•Polycyclic organic matter (POM). The assessment divided POM emissions into eightcategories. The first two categorieswere assigned a URE equal to 5% of that for pure benzo[a]pyrene (the same assumption that the 1996 assessment used forall POM data). Categories 3-7 were composed of emissions that were reported as individual compounds.These compoundswere placed in the category with an appropriate URE. Category 8, composed of unspeciated carcinogenicpolynucleararomatic hydrocarbons (a subset of POM called 7-PAH), was assigned a URE equal to 18% of that for purebenzo[a]pyrene.Details on the development of the 5% and 18% URE estimates are available here:http://www.epa.gov/ttn/atw/sab/appendixh.pdf.The process of URE estimation includes the following important sources of uncertainty:•Many of the substances in this assessment were classified as probable carcinogens, indicating that data were notsufficient to prove these substances definitely cause cancer in humans. It is possible that some of these substances arenot human carcinogens at environmentally relevant doses, and that the true risk associated with them is zero.November 7, 20057•All UREs used in this assessment were based on linear extrapolation from high to low doses. To the extent that truedose-response relationships for some substances arenonlinear, this assumption may result in significant over- orunderestimates of risk.•UREs for most of these substances were developed from animal data using conservative methods to extrapolate betweenspecies. Actual human responses may differ from the predicted ones.•Most UREs used in this assessment (typically, thosebased on animal data) were based on the statistical upperconfidence limit (UCL) of the fitted dose-responsecurve. That means true risk would probably be less, but could begreater. A few (typically, those based on human data) were based on the statistical best fit (“maximum likelihoodestimate,” or MLE). UREs based on the MLE are identified in a footnote to Table 1. This difference between UCL- andMLE-based assessments results in some UREs that aresomewhat less conservative than the rest.Table 1: Dose-Responses ValuesThis table lists includes dose-response values andsupporting information for both cancer and noncancer effects used in the 1999national-scale assessment. The EPA and IARC weight-of-evidence (WOE) categories characterize the extent to which availabledata support the hypothesis that a pollutant causescancer in humans. The EPA carcinogen categories are Group A—known,Group B1—probable, based on incomplete human data,Group B2—probable, based on adequate animal data, Group C—possible,Group D—not classifiable, and Group E—evidence of non-carcinogenicity. The IARC categories are Group1—carcinogenic inhumans, Group 2A—probably carcinogenic, Group 2B—possibly carcinogenic, Group 3—not classifiable, andGroup 4—probablynot carcinogenic. The URE is the upper bound riskestimate of cancer risk from a lifetime exposure toa concentration of 1microgram per cubic meter. The “RfC” column listsreference concentrations and similar values (i.e.,RELs, MRLs) that wereused in the initial 1996 national-scale assessment.The reference concentration (RfC) is an estimate,with uncertainty spanningperhaps an order of magnitude, of an inhalation exposure to the human population (including sensitivesubgroups) that is likely tobe without appreciable risks of deleterious effectsduring a lifetime. The “target system” columns show up to three organs or organsystem adversely affected at the lowest dose in human or animal studies. Other information on individual substances is shown infootnotes.November 7, 20058Chemical NameCAS No.EPAWOEIARCWOEURE(g/m3)-1URESourceUREDateRfC1(mg/m3)RfCSourceRfCDateTargetSystem 1TargetSystem 2TargetSystem 3Acetaldehyde275070B2 2B 0.000002IRIS 19970.009IRIS 1991RespiratoryAcetamide 603552B 0.00002CAL 1999Acetonitrile 75058D0.06IRIS 1999Whole bodyAcrolein210702830.00002IRIS 2003RespiratoryAcrylamide279061B2 2A 0.0013IRIS 19970.0007PCAL31997NeurologicalAcrylic acid 791070.001IRIS 1995RespiratoryAcrylonitrile2107131B1 2A 0.000068IRIS 19910.002IRIS 1997RespiratoryAllyl chloride 107051C 3 0.000006CAL 19990.001IRIS 1991NeurologicalAniline 62533B2 3 0.000001CAL 19990.001IRIS 1991SpleenAntimony compounds0.0002IRIS 1995RespiratoryArsenic27440382A 1 0.0043IRIS419970.00003CAL 2000DevelopmentalArsine 77844210.00005IRIS 1994HematologicalBenzene 71432A 1 0.000007IRIS420000.03IRIS 2003ImmunologicalBenzidine 92875A 0.067IRIS 19920.01PCAL31997Neurological LiverBenzotrichloride 98077B2 2B 0.0037Conv.Oral52004Benzyl chloride 100447B2 2B 0.000049CAL 1999Beryllium compounds2B1 1 0.0024IRIS 19980.00002IRIS 1998RespiratoryBis(2-ethylhexyl) phthalate2117817B2 2B 0.000002CAL 19990.01CAL 1999Respiratory LiverBis(chloromethyl) ether 542881A 1 0.062IRIS 1997Bromoform275252B2 3 0.000001IRIS 19971,3-Butadiene 106990A 2A 0.00003IRIS 20020.002IRIS 2002ReproductiveCadmium compounds2B1 1 0.0018IRIS 19920.00002CAL 2000KidneyCaptan 133062B2 3 0.000001Conv.Oral52004Carbon disulfide 751500.7IRIS 1995NeurologicalCarbon tetrachloride256235B2 2B 0.000015IRIS 19910.04CAL 2000LiverChlordane 57749B2 2B 0.0001IRIS 19980.0007IRIS 1998Liver1Includes EPA reference concentrations (RfCs) and similar values, i.e., California OEHHA reference exposure levels (RELs), and ATSDR minimum risk levels(MRLs).2EPA is currently developing a new dose-response assessment for this chemical. This situation will change as these assessments are completed and EPA beginsassessments for other substances. A current statusreport for all EPA assessments is available athttp://cfpub.epa.gov/iristrac/index.cfm.3Proposed by California OEHHA; not yet adopted in final form.4Maximum likelihood URE.5Conversion of oral potency slope to inhalation unit risk estimate was based on the following assumptions: (1) whole-life, continuous exposure, (2) inhalation rate of 20cubic meters of air per day, and (3) body mass of 70 kg. Further details are provided in the text, above.November 7, 20059Chemical NameCAS No.EPAWOEIARCWOEURE(g/m3)-1URESourceUREDateRfC1(mg/m3)RfCSourceRfCDateTargetSystem 1TargetSystem 2TargetSystem 3Chlorine 77825050.0002CAL 2000Respiratory2-Chloroacetophenone 5322740.00003IRIS 1991RespiratoryChlorobenzene 1089071CAL 2000Reproductive Kidney LiverChlorobenzilate 510156B2 0.000078HEAST 1997Chloroform267663B2 2B0.098ATSDR 1998LiverChloroprene21269980.007HEAST 1997RespiratoryChromium VI compoundsA 1 0.012IRIS419980.0001IRIS 1998RespiratoryCobalt compounds274404840.0001ATSDR 2001RespiratoryCoke Oven Emissions 8007452A 0.00062IRIS 1991Cresols (mixed) 1319773C0.6CAL 2000Neurological Whole bodyCumene 98828D0.4IRIS 1997Kidney EndocrineCyanide compounds2D0.003IRIS 1994Neurological Thyroid1,2-Dibromo-3-chloropropane96128B2 0.002CAL 19990.0002IRIS 1991Reproductivep-Dichlorobenzene2106467C 2B 0.000011CAL 19990.8IRIS 1994Liver3,3'-Dichlorobenzidine 91941B2 2B 0.00034CAL 1999Dichloroethyl ether 111444B2 0.00033IRIS 19971,3-Dichloropropene 542756B2 2B 0.000004IRIS 20000.02IRIS 2000RespiratoryDichlorvos 62737B2 2B 0.000083Conv.Oral520040.0005IRIS 1994NeurologicalDiesel emissionsB10.005IRIS 2003RespiratoryDiethanolamine 1114220.003CAL 2001Respiratory3,3'-Dimethoxy benzidine 119904B2 2B 0.000004Conv.Oral52004p-Dimethylamino azobenzene 601172B 0.0013CAL 19993,3'-Dimethylbenzidine 119937B2 0.0026Conv.Oral52004Dimethyl formamide 681222B0.03IRIS 1999Liver2,4-Dinitrotoluene 121142B2 2B 0.000089CAL 19970.007PCAL31997Liver Neurological1,4-Dioxane2123911B2 2B 0.000003Conv.Oral520043CAL 2000Liver HematologicalKidney1,2-Diphenylhydrazine 122667B2 0.00022IRIS 1991Epichlorohydrin 106898B2 2A 0.000001IRIS 19970.001IRIS 1992Respiratory1,2-Epoxybutane 1068870.02IRIS 1992RespiratoryEthyl acrylate 140885B2 2B 0.000014Conv.Oral52004November 7, 200510Chemical NameCAS No.EPAWOEIARCWOEURE(g/m3)-1URESourceUREDateRfC1(mg/m3)RfCSourceRfCDateTargetSystem 1TargetSystem 2TargetSystem 3Ethylbenzene2100414D1IRIS 1991DevelopmentalEthyl carbamate 517962B 0.00029CAL 1999Ethyl chloride 7500310IRIS 1991DevelopmentalEthylene dibromide 106934B2 2A 0.00022IRIS 19970.0008CAL 2001ReproductiveEthylene dichloride2107062B2 2B 0.000026IRIS 19972.4ATSDR 2001LiverEthylene glycol 1072110.4CAL 2000RespiratoryEthylene oxide275218B1 1 0.000088CAL 20040.03CAL 2000NeurologicalEthylene thiourea 96457B2 2B 0.000013CAL 19990.003PCAL31997EndocrineEthylidene dichloride 75343C 0.000001CAL 19990.5HEAST 1992KidneyFormaldehyde250000B1 2A 5.5e-9EPAOAQPS20040.0098ATSDR 1999RespiratoryGlycol ether compounds20.02EPAOAQPS2000ReproductiveHexachlorobenzene 118741B2 2B 0.00046IRIS 19970.003PCAL31997LiverHexachlorobutadiene287683C 3 0.000022IRIS 19970.09PCAL31997ReproductiveHexachlorocyclopentadiene277474E0.0002IRIS 2001RespiratoryHexachloroethane 67721C 3 0.000004IRIS 19970.08PCAL31997Kidney Liver NeurologicalHexamethylene-1,6-diisocyanate8220600.00001IRIS 1994Respiratoryn-Hexane21105430.2IRIS 1991Neurological RespiratoryHydrazine 302012B2 2B 0.0049IRIS 19970.0002CAL 2000Liver ThyroidHydrochloric acid 76470100.02IRIS 1995RespiratoryHydrofluoric acid 76643930.03CAL 1999SkeletalIsophorone 78591C 2.7e-7Conv.Oral520042CAL 2001Liver DevelopmentalLead27439921B2 2B0.0015EPAOAQPS62003DevelopmentalLindane (all isomers)2B 0.00053IRIS 19880.0003PCAL31997Kidney Liver ReproductiveMaleic anhydride 1083160.0007CAL 2001RespiratoryManganese compoundsD0.00005IRIS 1993NeurologicalMercury compoundsC0.00009CAL 2000NeurologicalMethanol2675614CAL 2000Developmental6EPA has not developed an RfC for lead. The valueshown is the quarterly National Ambient Air QualityStandard for lead, which EPA believes to be without significantadverse effects.November 7, 200511Chemical NameCAS No.EPAWOEIARCWOEURE(g/m3)-1URESourceUREDateRfC1(mg/m3)RfCSourceRfCDateTargetSystem 1TargetSystem 2TargetSystem 3Methyl bromide 74839D0.005IRIS 1992RespiratoryMethyl chloride 74873D0.09IRIS 2001NeurologicalMethyl ethyl ketone 789335IRIS 2003DevelopmentalMethyl isobutyl ketone 1081013IRIS 2003DevelopmentalMethyl isocyanate 6248390.001CAL 2001Respiratory Whole bodyMethyl methacrylate 80626E0.7IRIS 1998RespiratoryMethyl tert-butyl ether216340443IRIS 1993Liver Kidney Ocular4,4'-Methylene bis(2-chloroaniline)101144B2 2A 0.00043CAL 1999Methylene chloride275092B2 2B 4.7e-7IRIS 19971ATSDR 2000LiverMethylene diphenyldiisocyanate101688D0.0006IRIS 1998Respiratory4,4'-Methylenedianiline 1017792B 0.00046CAL 19990.02CAL 2002OcularNaphthalene291203C 2B 0.000034CAL 20040.003IRIS 1998RespiratoryNickel compounds2A 2B 0.00016EPAOAQPS20040.000065CAL 2000Respiratory ImmunologicalNitrobenzene298953D 2B0.03PCAL31997Respiratory2-Nitropropane 79469B2 2B 0.000005EPAOAQPS20030.02IRIS 1991LiverNitrosodimethylamine 62759B2 2A 0.014IRIS 1997N-Nitrosomorpholine 598922B 0.0019CAL 1999PCB Group 1336363B2 2A 0.0001IRIS 1999Pentachloronitrobenzene 82688C 3 0.000074Conv.Oral52004Pentachlorophenol287865B2 2B 0.000005CAL 19990.1PCAL31997Liver KidneyPhenol 108952D 30.2CAL 2000LiverPhosgene2754450.0003PCAL31997RespiratoryPhosphine 7803512D0.0003IRIS 1995Whole bodyPhthalic anhydride 854490.02CAL 2000Respiratory OcularPolycyclic organic matter7group 1280.000055OAQPS 2004Polycyclic organic mattergroup 2280.000055OAQPS 20047A full discussion of the risk assessment for polycyclic organic matter is available at: http://www.epa.gov/ttn/atw/sab/appendix-h.pdf.8EPA WOE varies among individual compounds.November 7, 200512Chemical NameCAS No.EPAWOEIARCWOEURE(g/m3)-1URESourceUREDateRfC1(mg/m3)RfCSourceRfCDateTargetSystem 1TargetSystem 2TargetSystem 3Polycyclic organic mattergroup 3280.1OAQPS 2004Polycyclic organic mattergroup 4280.01OAQPS 2004Polycyclic organic mattergroup 5280.001OAQPS 2004Polycyclic organic mattergroup 6280.0001OAQPS 2004Polycyclic organic mattergroup 7280.00001OAQPS 2004Polycyclic organic mattergroup 8280.0002OAQPS 20041,3-Propane sultone 11207142B 0.00069CAL 1999Propylene dichloride 78875B2 0.000019Conv.Oral520040.004IRIS 1991RespiratoryPropylene oxide 75569B2 2B 0.000003IRIS 19970.03IRIS 1992RespiratoryQuinoline 91225B2 0.0034Conv.Oral52004Selenium compoundsD0.02CAL 2001Neurological Liver HematologicalStyrene21004252B1IRIS 1992NeurologicalStyrene oxide 960932A0.006PCAL31997Respiratory1,1,2,2-Tetrachloroethane 79345C 3 0.000058IRIS 1997Perchloroethylene2127184B2C 2A 0.000005CAL 19990.27ATSDR 1999NeurologicalTitanium tetrachloride 755045020010.0001ATSDR 1999RespiratoryToluene2108883D 30.4IRIS 1995Respiratory Neurological2,4-Toluene diamine 95807B2 0.0011CAL 19992,4-Toluene diisocyanate 264716252B 0.000011CAL 19990.00007IRIS 1995Respiratoryo-Toluidine 95534B2 2B 0.000051CAL 1999Toxaphene 8001352B2 2B 0.00032IRIS 19971,2,4-Trichlorobenzene 120821D0.2HEAST 1993Liver1,1,2-Trichloroethane 79005C 3 0.000016IRIS 19970.4PCAL31997Liver1,1,1-Trichloroethane271556D1CAL 2000NeurologicalTrichloroethylene279016B2C 2A 0.000002CAL 19990.6CAL 2000Ocular2,4,6-Trichlorophenol 88062B2 0.000003IRIS 1997Triethylamine 1214480.007IRIS 1991RespiratoryNovember 7, 200513Chemical NameCAS No.EPAWOEIARCWOEURE(g/m3)-1URESourceUREDateRfC1(mg/m3)RfCSourceRfCDateTargetSystem 1TargetSystem 2TargetSystem 3Trifluralin 1582098C 3 0.000002Conv.Oral52004Vinyl acetate21080542B0.2IRIS 1990RespiratoryVinyl bromide 593602B2 2A 0.000032HEAST 19970.003IRIS 1993LiverVinyl chloride 75014A 1 0.000008IRIS920000.1IRIS 2000LiverVinylidene chloride275354C0.2IRIS 2002LiverXylenes (mixed) 13302070.1IRIS 2003Neurological9URE based on whole life exposure was selected overa URE based on adult exposure only.