Document yrNnmgJro52zyXQowDzgeJoyd

SB9 HAIXMM, PMTKUBQttP Assccunow EPA-450/ -89- CANCER RISK FROM OUTDOOR EXPOSURE TO AIR TOXICS A U.S. Environmental Protection Age. Office of Air* Quality PUnnin.j and SUndart* Research Triangle Park, North Carolina 27711 September 1989 + POLLUTANT TABLE 2-6 (concluded) UNIT RISK FACTORS USED TO COMPARE CANCER RISK EPA CLASSIFICATION* UNIT RISK FACTORS REFERENCE P 76. 1,1,2,2-Tetrachloroethane 77. Thiourea 78. Toxaphene 79. 1,1,2-Trichloroethane 80. Trichloroethylene 81. 2,4,6-Trichlorophenol 82. Vinyl chloride 83. Vinylidene chloride C B2 B2 C B2 82 A C 5.8x10'* 5.5x10'* 3.2x10*? 1.6x10** 1.7x10** V 5.7x10** ^ 4.1x10** 5.0x10** 3 3 3 3 2 3 2C 1 * For a discussion of how EPA evaluates suspect carcinogens and more information on these classifications, refer to "Guidelines for Carcinogen Risk Assessment" (51 Federal Register 33992). The EPA classifications used in this report .are: A * proven human carcinogen B - probable human carcinogen (B1 indicates limited evidence from human studies; B2 indicates sufficient evidence from animal studies but inadequate evidence from human studies) * C * possible human carcinogen b Based on inhalation study. Oral study suggests a unit risk factor of 3.3x10. Oral studies suggest a unit risk factor of 4.2x10. U.S. Environmental Protection Agency, Office of Research and Development, Office of Health and Environmental Assessment. Health Effects Assessment Summary January 1989. 1. Integrated Risk Information System. 2. Office of Health and Environmental Assessment. 3. U.S. Environmental Protection Agency. Hazardous Waste TSOF - Background Information for Proposed RCRA Air Emission Standards, Volume II - Appendices. Preliminary Oraft. March 1988. pp. E*8 through E-13. 4. Oraft Supplemental Rule for Hazardous Waste Incinerators. Appendix B, Unit Risks for Carcinogenic Constituents. 5. IEMP-Phlladelphia. Developed from EPA's Orinking Water Criteria Document. 3/2/84. 6. U.S. EPA, Office of Solid Waste. 7. Southeast Chicago Study. % 2-21 VAB.OOOl 154166 A AeryVia Benzene* BaP.^'-& Beiylll h7oreform zZJjti'n* aicrcnnae Ethylene oxide Formaldehyde Gasoline vapors Methyl chloride Methylene chloride Nickel (subsulfide) Perchloroethylene Propylene oxide Styrene Trichloroethylene Vinyl chloride Vinylidene chloride 1.7x10"* 6.9x10"* 3.3xl0*3 4.0xl0`4 4.6xl0'7 2.3xl0*3 1,0x10* 5 3 6 4 6 7 *7 -7 1 1 *7 3.3x10 1 *4 6 1 4 2 4 Z 7 6 *6 4 2xl0`-55 -- --^ June 1988 1.1x10 3 8.3x10 6 1.7x10 3 2.4x10 3 2.8x10 1.8x10 *3 2.3x10 -S :.2x:c i.^XlO*'* 1.0x10** 1.3x10** 6.6xl0*7 3.6x10** 4.7xl0*7 4.8x10** 5.8xl0*7 3.7x10**5.7xl0*7 1.7x10** 4.1x10** 5.0x10** % Change +6400 +20 -48 +500 +60770 -22 +130 445 -57 -72 +113 -12 +2,470 +161 +45 -66 -97 +97 -59 *58 -r!9 3-51 VAB.0001154167 TAUl.K I. KNOWN HUMAN CARCINOGENS tContinued ^<-0 Pq Sul ml slice Tubucco moke' Trcosul|liuu I Vinyl elilorlde CAS No KikI Use/Processcs/Productlon Unit Risk Factor** 199-75-3 75-01-4 ftltllgnant tmura of the respiratory tract and npper digestiva tract are causally related to sucking various forma of tobacco. Millgnant tutora of Ilia hladJer, renal pelvis, aial pancreas are causally related to sinking cigarettes.* Produced only lu ncisinrk since I960. Used In laiiun ncdleine for treating ovarian cancer. Used In Ilia production of plasties, and Ilia synthesis of other chonlcals. Vinyl chloride - vinyl acetate npolyieri are used In the nunufseture of vinyl asbestos floor tiles. Antutsl production la about 1 billion pounds for Ilia nuiMMcr and S billion pounds for Ilia haiitpolymer. 4.1 III Maryland* llb/ycur) Produced Handled Total Aucricau (hrinical Society llusnlcal Abstract Service Registry Ruber. Source used tierei Registry of Tbslc Kffccta of Otonlcal Stibsloticcs NIC Ml 1074 edition. ...... .... /b I'robnhl Illy or contracting cancer If exposed to 1 ug/trr of a carcinogen for 70 years. Sourcei Personal OiiuiuileatIon, M.A. Unvlellu to Miko Losetains, IPA/QKJPS/PAII. Mtrcli 19SS. . Iltesa factors are sub|ccl to chonge and alinnld be con ft mmI with FJA*a (hrelnogcn Aasesaiunt droop before use. Iteryl J hut cui|hjuimI* of cutuurdal lupor lance. Source for 97 |M$rcunl of all arscnlu products. * Represents 94 percent of U.8. consisiptlon. r Source i * Mtryland Tostc Suttslancc Registry Syslatt - Office of Div I roumcii I a 1 Prugrisiw, Science and lk>ltli Advisory Croup, OmuiIcs) Inventory |98a t}uiutily by tlHiiilcal for Stale of Itirylaod. (Wanks I tall cate I lie substance mi not Included in 1993 survey.) * Sour IAJI* Almugritjih* on IImj Evaluation of tho Oirelnogenlc Itlak of Uumicala to tkamnsi Vol. l-lt. International Agency for Kcsciircli on Omccr b Suiircct 'llie Ibiulcnsod thunlcsl Dictionary, TenlIt Idllion. Van Nostrand llulnliuld (toipany, New York, 1991 I Source! 'Ihe kbrek Index, Ninth Edition, Ibrck and Oxipany, Rahway, Net* Jersey, 1976. 03-03-97 1 Listed by lAJi: but nut by Nil*. ^ Listed by Nil* lint not by IA1I\ Sourcet (Utiles* otherwise noted) 'third Anmml fh'|K>rt on (hreluogenst Service*, Scnliaihcr 1983. Siimury, National `Ibxlcolugy Program, U.S. Ucpnr tuent of licnlth mu I Usiun V^.0001154168 ig process, the AALs Iviw: not b^on i rnployed as strict ambient exposure standards. In general, the states have used the AALs as guides, and if the limit for a pollutant is exceeded then the industry and regulatory agency tend to develop a mutually acceptable plan to reduce ex posure. One difficulty is that the AALs are often derived by a unit or agency other than that which handles the per mitting process (e.g., the Department of Public Health versus the Department of Environmental Protection/Manage ment). The permitting group is usually not firmly bound by the AALs; the AAL is just one of a number of factors to be considered in the permit process, which essentially is a risk management process (8). Another aspect of the air toxics issue is the implementation of SARA Title 313, which requires reporting of rou tine emissions (in pounds per year) to communities. What do these numbers mean in terms of human health? Risk communication is likely to be a major challenge for the industries and states, and it is likely that major differences of How this may then affect the derivation of AALs and the permitting process re mains to be seen. In summary, the EPA air toxics strat egy has led to the development of a highly decentralized approach for the regulation of air toxics at the state level, This in turn has led to the deriva tion of highly variable acceptable-exposure guidelines for mutagens, carcino gens, teratogens, and systemic toxicants. Such interstate variability in AALs for toxic substances may lead to differential protection of the public health from air toxics, confuse the pub lic about air pollution and health con cerns, and undercut the credibility of public health and environmental regula tory agencies. It is interesting to note that while EPA encouraged the development of such divergence in air toxics regulatory approaches and implementation at the state level, the Food and Drug Admin istration funded a National Academy of Sciences (NAS) assessment of the fed eral process of risk assessment. The goal was to determine if greater con sistency could be achieved across agen- regulation of chronic health hazards. This effort resulted in the publication of the highly influential work, Risk ajsessment in the Federal Government: Managing the Process (11). Thus, while the NAS report ad dressed the lack of agreement in assess ing risk at the federal level and recom mended ways to minimize it, EPA was encouraging just the opposite with re spect to air toxics regulation at the state level. For example, the NAS commit tee strongly recommended "that uni form inference guidelines be developed for the use of federal regulatory agen cies in the risk assessment process** (12). Although there can be compelling reasons for different emission regula tions in different regions and states, EPA should strongly encourage the development of consistent risk assess ment methodologies that assist the risk manager in the final decision-making process. References (1) Calabrese, E. J. Methodologic Ap proaches to Deriving Environmental and Occupational Health Standards; Wiley: New York, 1978. * A TABLE 2 Highest and lowest ambient air levels (AALs) standardized to a 24-h averaging time by compound for representative known and probable human carcinogens, in /tg/nri3 Compound__________ Acrylonitrile Arsenic and compounds as As Benzene Eplchlorohydrln Ethylene dibromlde Ethylene oxide Formaldehyde Nickel subsulfide PCBs Vinyl chloride Original AAL 15 (NY) Standardized highest AAL 257 0.67 (NY) 100 (NY, Rl) 33.3 (NY) 1500 (VA) 450 (IN) 7.2 (Philadelphia) 24 (NV) 1.67 (NY) 6.57 (Philadelphia) 11.5 1718 572 1500 160 123.7 8.54 28.7 112.9 Original AAL 0.15 (MA) 0.0002 (Rl) 1.2 (MA) 2.7 (MA) 0.045 (NC) 0.01 (Rl) 0.77 (MA) 0.0017 (NC) 0.0081 (MA) 0.038 (NC) Standardized lowest AAL 0.15 0.0034 1.2 2.7 0.773 0.17 0.77 0.029 0.0081 0.65 Ratio standardized hlghest/toweat AAL 1713 3382 1432 212 1940 941 161 294 3543 174 *The original AALa and their averaging times were obtained Irom Reference 4. These substances are ell classified In IARC groups 1 or 2A. AALs were standardized to 24*h averaging times for convenience based on information provided in Reference tv Annual averaging times are In reality more appropriate for chronic endpoints such as carcinogenicity. These figures are highest and lowest standardized AALs; other state end local agencies may have had higher or lower original AALs. When unstandardized highest and lowest AALs are compared, the differences are generally larger. TABLE 3 Highest and lowest ambient air levels (AALs) standardized to a 24-h averaging time by compound for representative noncarcinogens, in /zg/m3 * Compound Acetone Ammonia Ethylene glycol Mhexane Napthalene Phenol Toluene Xylenes Original AAL 35.6 (NY) 0.36 (NY) 2.976 (NY) 30 (VA) 0.167 (NY) 0.456 (Philadelphia) 7.5 (NV3 1.45 (NY) Standardized highest AAL 611,7 6.186 1.06 30 , 2.87 7.84 128.9 24.91 Original AAL 11.8 (CT, SD) 0.024 (MA) 0.17 (MA) 1.8 (ND) 0.014 (MA) 0.095 (IN) 0.051 (MA) 0.0592 (MA Standardized lowest AAL 4.2 0.024 0.17 0.64 0.014 0.034 0.051 0.0592 Ratio standardized highest/lowest AAL 146 258 6.2 47 205 230 2527 421 The original AALs and their averaging times were obtained from Reference 4. Units are standardized to 24 h for comparison, based on Information provided In Reference 11. These figures are highest and lowest standardized AALs; other state and local agencies may have had higher or lower original AALs. When unstandardized highest end lowest AALs are compared, the differences are generally larger. Environ. Scl. Technol., Vol. 23, No. 11, 1689 1327 VAB.0001154169