Document babJY8ZEbR6zxg1yGMKKNXy61

WILLIAM D. RUCK C L9 M AU9 albert j. eeveiooe. m ICMRO M. TAIBSANKS, HI KtKRr L.QIAMONO OART M. OAlSE ROBERT 9. tiqmoR KEVIN M. fOLtr A.JAMCS BARNE5 MAROLO MIMMtLMAN i.aw ornces RUCKEtSHAUS, BEVERIDGE. FAIRBANKS & DIAMOND One Farragut Souare South Washington, D. C. 20006 TeLCRMQNC (2021 636-7800 December 16, 1975 CARL C AWOLE V LEONARDG**m(xT or COUNSEL CABLE ADORES* "INOLAW* Mr. Jerome Heckman Keller & Heckman 1150 17th Street, N. W. Washington, D. C. 20036 Dear Jerry: Today EPA designated vinyl chloride as a hazard ous pollutant and proposed an air pollution standard to limit emissions of vinyl chloride from all existing and new plants in the country. Rather than going in to a lot of detail, I am attaching a copy of Mr. Train's press release and a summary of the Quantitative Risk As sessment for Community Exposure to Vinyl Chloride. These two documents provide a quick summary of what the Agency did today. At the press conference Mr. Train did endorse the concept of cost-risk-benefit analysis in regulating substances such as vinyl chloride. In my opinion this is a major step forward by the Agency. Sincerely yours. Enclosures William D. Ruckelshaus SPI-24561 quantitative risk assessment FOR - COMMUNITY EXPOSURE TO VINYL CHLORIDE SUMMARY Vinyl chloride has produced liver angiosarcoma, a very rare form of cancer, as well as primary cancers at other sites and serious liver damage in workers employed in plants producing vinyl chloride monomer .(VCM) and polyvinyl chloride (PVC). People living near these plants * are also at some risk of adverse effects due to their exposure to vinyl jchloride in the ambient air near the plants. Should the environmentally' exposed population be the same size'as it is now, and should it remain exposed to current level of vinyl chloride, we estimate that between thai\ one_ and-ten cases of angiosarcoma of the liver wi-J 1 -occur per ye&f:due to environmental vinyT chloride exposure. Due to the 15 to 20 'ye^r^a-tency time of this disease, cases initiated this year will probably not be "diagnosed until 1991 to 1995. I-n'addition we estimate that an %quaT num5er of'cancers at other primary organ sites' are being produced by vinyl chloride each year, bringing the tota.l number of cancer cases to somewhere in the range between 20 and less than one case per-year. The successful implementation of the regulations is expected to reduce ambient vinyl chloride levels around plants to about 5 percent of current concentrations, and consequently to reduce the frequency of adverse health effects to 5 percent of the foregoing rates. These estimates are based on several considerations. From 1970 census data, it was estimated that 4.6 million people live within five miles of the plants affected by these regulations. Standard methods of diffusion modeling showed that the average concentration of vinyl chloride SPI-24562 r.'ver a five mile region surrounding the plants.is currently 17 parts per billion, A linear dose-response relationship extrapolated to zero with no threshold dose was assumed for these effects. The estimate 'of liver angiosarcoma frequency was based on the available animal doseresponse.information from controlled experiments and on the available information on adverse effects in highly exposed workers in the industry. .i The above estimates of the incidence of liver cancer involve a substantial degree of uncertainty. These estimates should be validated .by epidemioUgical studies of neighborhoods around VC plants, not only for liver cancer but other forms of cancer, liver disease, and birth defects.'- Suggestive evidence for an Increased incidence of birth defects hascrecently been reported.- An.epidemiological study of.the cancer r'xnerienp. arpynd VC plants has .been.initiated but.at 1 east-cne year will be required to obtain some solid information. Complete copies of the risk assessment are available from Gary Robinson EPA Press Office (202) 755-0344. SP 4-24563