Document zdJOyQvkRZvJgeZ03RdOoj28B

TO: D. Angell J. Driskill J. Fike R. Jacobs R. Samelson J. Wyche inter-office Correspondence DATE: January 21, 1993 FROM J. A- Barter LOC: 36-W SUBJECT: CAAA List of "High Risk" Air Pollut ants, Deletion of Vinylidene Chloride and 1,1,2,2- tetrachloroethane from final list In a December 29, 1992 Federal Register notice (57FR 61970), the EPA published the final rule establishing a list of "high risk" chemicals. Although both vinylidene chloride and 1,1,2,2-tetrachloroethane were initially proposed for inclusion on the list, neither was included in the final rule. The CMA VDC Panel had commented on the proposed rule. Copies of a memo summarizing the VDC actions and the final EPA rule are attached for your information. / JAB/dt SL 063362 t LCE O PAUL ROBERT R HASTINGS LEONARD S, JANOFSKV CHARLES M WALKER los angeles office SS5 south flower street LOS ANGELES, CALIFORNIA 90071-2371 TELEPHONE (213) 6A3-6000 ORANGE COUNTY OFFICE 6fifi TOWN CENTER DRIVE COSTA MESA, CALIFORNIA 92020-192+ TELEPHONE (71+) 666-6200 WEST LOS ANGELES OFFICE 1299 OCEAN AVENUE SANTA MONICA. CALIFORNIA 90+01-1070 TELEPHONE (310) 319-3300 WRITER'S DIRECT DIAL NUMBER 202-457-9423 law offices of Paul. Hastings. Janofsky & Walker a Partnership including aropessiDnal corporations twelfth FLOOR 1050 CONNECTICUT AVENUE. N W. WASHINGTON, D C. 20036-9331 TELEPHONE (202) 223*9000 TWX 710-922-9092 FACSIMILE (202) 462-BI49 ATLANTA OFFICE GEORGIA-PACIFIC CENTER U3 PEACHTREE STREET N E ATLANTA, GEORGIA 30303-1540 TELEPHONE 1404} 50-900 CONNECTICUT OFFICE 1055 WASHINGTON BOULEVARD STAMFORD, CONNECTICUT OB9CI-22I7 TELEPHONE (203) 9*1-7+00 NEW YORK OFFICE 399 PARK AVENUE NEW YORK, NEW YORK I0022-+B97 TELEPHONE (212) 310-9000 January 4, 1993 TOKYO OFFICE toranomon ohtori ouilding +-3, TORANOMON l-CHOMC MINATO-KU. TOKYO 109 TELEPHONE (03) 3007-0730 ? Far Dlitrlfeutlett by MA MEMORANDUM TO THE CMA VINYLIDENE ^LoRIDE fANEL Re: Successful Deletion of VDC from EPA's Proposed List of "High Risk" Air Pollutants In July 1991, the Panel filed comments on an EPA proposal to list VDC as a "high risk" pollutant, pursuant to the air toxics provisions of the Clean Air Act Amendments of 1990 C'CAAA"). The final rule establishing EPA's "higl?*5, risk" air pollutant list recently was published in the Federal Register. 57 Fed. Reg. 61970 (December 29, 1992), and we are pleased to report that VDC has been deleted from the list. Background on the Importance ___of the "High Risk", List JAN 81993 The CAAA include certain inducements for facilities which make early reductions in total emission of hazardous air pollutants ("HAPs"). The law specifies, SL 063363 memorandum for the cma vinylidene chloride panel January 4, 1993 Page 2 however, that facilities cannot be permitted to benefit from a net reduction in HAP emissions if it is accomplished whil increasing substantially the emission of certain "high risk" HAPs. To implement these legal requirements, EPA has promulgated a "high risk" HAP list which identifies such chemicals and assigns each a "weighting factor" which EPA believes corresponds to the magnitude of the risk posed by the particular chemical. "High risk" HAPs have "weighting factors" between 10 and 100,000, while all other HAPs have a "weighting factor" of 1. (In its 1991 proposal, EPA listed VDC as a "high risk" HAP and assigned it a "weighting factor" of 10.) Under the final !e, a facility seeking to qualify for early reduction edit will need to "offset" any increase in emission of a "high risk" HAP with a more substantial decrease in emission of other HAPs. For example, a 1 ton increase in emission of a "high risk" HAP with a "weighting factor" of 100 would need to be offset by a 100 ton reduction in emission of other HAPs. In addition to the use of the "high risk" list in EFA's early reduction program under the CAAA, EPA and other state and federal regulatory agencies may look to the list as an authoritative source of chemicals deserving of SL 063364 > 4 memorandum for the cma vinylidene chloride panel January 4, 1993 Page 3 particularly stringent regulation. This phenomenon may have tremendous future implications for chemicals included on the list. Relevant Changes Reflected In EPA's Final "High Risk" List The final "high risk" HAP list contains 47 compounds and classes of compounds. See 57 Fed. Reg. at 61981. The changes to the list from the proposal include the addition of 17 chemicals, and the deletion of 5, including VDC. The following excerpts from the Panel's July 1991 comments summarize the principal position we advocated: "In view of the uncertainty over whether VDC poses any carcinogenic risk to humans, it is improper to extrapolate from the one positive study using traditional quantitative risk assessment principles to conclude that VDC poses a 'high risk.' EPA's use of identical methods to extrapolate human risk estimates for substances classified as known (Group A), probable (Group B) and possible (Group c) carcinogens ignores fundamental differences in the quality of the carcinogenicity data for these substances. If VDC is not a human carcinogen, it poses no risk of cancer and it should not be listed as a 'high risk' carcinogen. By ignoring the important differences among carcinogenity groups, EPA's listing of VDC as a 'high risk' pollutant would be arbitrary and capricious." *** SL 063365 MEMORANDUM FOR TH1 January 4, 1993 Page 4 A VINYLIDENE CHLORIDE PANEL "EPA has mechanically adopted and applied [the] VDC [carcinogenicity] inhalation unit risk estimate in the same way as it has applied the unit risk estimates for vinyl chloride and benzene -- known human carcinogens. It ignores the substantial limitations and uncertainties which the Agency itself has said are inherent in the VDC unit risk estimate." The preamble to EPA's final rule provides a brief explanation of the basis for EPA's ultimate decision to assign VDC a "weighting factor" of 1 and thus to remove it from the "high risk" list: "In the final rule, carcinogens, with a Group C classification (possible human carcinogens) have been assigned a lower weight. Greater uncertainty exists regarding the evidence for a Group C classification than that existing for chemicals classified as Group A (know human carcinogen) or B (probably carcinogenic to humans). A Group C classification is defined by positive carcinogenicity in a single experiment >. tumor response of marginal statist! significance, or finding benign tumors only .... The greater uncertainty regarding a Group C Classification is reflected in a lower weighting factor. As a result, two Group C carcinogens (1,1,2,2-tetrachloroethane and vinylidene chloride) have been assigned weighting factors of 1 rather than 10 as proposed." *** "Numerous commenters requested that specific pollutants be removed from the high-ri list. Most of the commenters took iss with the scientific basis of EPA potency f ars or other specifics of the scientific .dies SL 063366 > MEMORANDUM FOR THE CMA VINYLIDENE CHLORIDE PANEL January 4, 1993 Page 5 that document the health effects. As stated above, three chemicals were deleted from the list because of health effects data and two were assigned weighting factors of one because of their Group C cancer classification. All other requests to delete pollutants from the list were denied." 57 Fed. Reg. at 61983, 61985. A copy of pertinent excerpts from EPA's preamble to the final rule accompanies this memorandum. R. Bruce Dickson Randall M. Stone SL 063367