Document mpBxvo5Ozem8qy3qvmv1wyMMd

fa The "m Vinyl y / a Instikne Division of The Society of The Plastics Industry, Inc. November 5, 1990 TO: Health, Safety and Environment Committee RE: CARB Hearings on Vinyl Chloride Scheduled for 12/13 or 12/14 The California Air Resources Board has announced that at its public hearings scheduled for December 13th or 14th the Board will consider the adoption of a regulatory amendment which would identify vinyl chloride as a toxic air contaminant and recommend that it be listed with "no identified threshold exposure level below which no significant adverse health effects are anticipated". As you know, the VI submitted comments during the preparation of the background documents. Attached is the Notice of Public Hearing which I received today. Also enclosed is a copy of the Executive Summary of the Board staff report as approved by the Scientific Review Panel on October 19th. I have the Technical Support Document (3 volumes). Copies are also available through the Board's Public Information Office at (916)322-2990. As noted, if the VI intends to file any written comments they are requested, although not required, to be submitted 10 days before the hearing. Please advise me by November 19th whether you believe any comments (written or oral) need to be prepared. MNS/pmb CTL018874 Wayne Interchange Plaza II 155 Route 46 West Wayne, NJ 07470 (201) 890-9299 Fax If (201) 890-7029 TITLES 17 AND 26. CALIFORNIA AIR RESOURCES BOARD. NOTICE OF PUBLIC HEARING TO CONSIDER THE ADOPTION OF A REGULATORY AMENDMENT IDENTIFYING VINYL CHLORIDE AS A TOXIC AIR CONTAMINANT. The Air Resources Board (the "Board") will conduct a public hearing at the time and place noted below to consider the adoption of a regulatory amendment identifying vinyl chloride as a toxic air contaminant (TAC). In addition to identifying vinyl chloride as a TAC, the proposed regulatory amendment specifies that there is not sufficient available scientific evidence to support the designation of a threshold exposure level below which no significant adverse health effects are anticipated. DATE: December 13, 1990 TIME: 9:30 AM PLACE: Bay Area Air Quality Management District Building 7th Floor Boardroom 939 Ellis Street San Francisco, California This item will be considered at a two-day meeting of the Board which will start at 9:30 a.m.f December 13, 1990 and will continue at 8:30 a.m., December 14, 1990. Please consult the hearing agenda (available at least 10 days before December 13, 1990) to determine the day on which this item will be considered and the order in which scheduled items will be considered. INFORMATIVE DIGEST OF PROPOSED ACTION Sections Affected: Section 93000, Titles 17 and 26, California Code of Regulations. Assembly Bill 1807 (Stats. 1983, ch. 1047; Health and Safety Code section 39650 et seq., Food and Agriculture Code section 14021 et seq.) sets forth procedures for the identification and control of toxic air contaminants in California. In accordance with those procedures, staff is proposing that the Board amend section 93000 of Titles 17 and 26, California Code of Regulations, by adding vinyl chloride to the list of toxic air contaminants. The staff further proposes that vinyl chloride be listed with no identified threshold exposure level below which no significant adverse health effects are anticipated. In accordance with Health and Safety Code sections 39660 and 39661, the Department of Health Services (DHS) staff has prepared an evaluation of the health effects of vinyl chloride which is included in the Technical Support Document referenced in the Board's Staff Report on vinyl chloride. The DHS staff found that vinyl chloride is an animal and human carcinogen. The DHS staff also found that there was not sufficient scientific evidence to CTL018875 support the designation of an exposure level below which carcinogenic effects would not have some probability of occurring and recommended that vinyl chloride be treated as having no identified threshold. The Scientific Review Panel (SRP), established pursuant to Health and Safety Code section 39670, reviewed the Technical Support Document on vinyl chloride and submitted written findings to the Board, in accordance with Health and Safety Code section 39661. The SRP found no serious deficiencies in the report on vinyl chloride. The SRP agreed with the staff recommendation that vinyl chloride should be listed as a toxic air contaminant. The SRP also found that there is not sufficient scientific evidence to support the designation of a vinyl chloride threshold exposure level below which no significant adverse health effects are anticipated. In accordance with Health and Safety Code section 39662, the Board staff prepared this hearing notice as well as a proposed regulation identifying vinyl chloride as a toxic air contaminant with no designated threshold exposure level. No control measures for vinyl chloride will be proposed for adoption at the hearing. If vinyl chloride is listed as a toxic air contaminant, a report on the need for and appropriate degree of, control measures to reduce vinyl chloride emissions will be developed in accordance with Health and Safety Code sections 39665 and 39666. Vinyl chloride has been identified by the U.S. Environmental Protection Agency as a hazardous air pollutant pursuant to section 7412 of Title 42 of the United States Code (40 CFR 61.01.). AVAILABILITY OF DOCUMENTS AND CONTACT PRSQH The Board staff, with the participation of the DHS staff, prepared a Staff Report which serves as the initial statement of reasons for this proposal. The Staff Report summarizas the basis for the proposed regulation, the environmental impacts of the proposal, and the findings of the SRP. The Technical Support Document reviewed by the SRP is referenced in the Staff Report. The Technical Support Document consists of Part A, "Public Exposure to, Sources, and Emissions of Yinyl Chloride," prepared by the Board staff; Part 3, "Health Effects of Airborne Vinyl Chloride," prepared by the DHS; and Part C, "Staff Responses to Public Comments on the Yinyl Chloride Report," prepared by the staffs of the Board and the DHS. The Staff Report and the Technical Support Document, the full text of the proposed regulation, and any other information on which the proposal is based, will be available for inspection at the Board's Public Information Office, 1102 Q Street, Sacramento, California 95814, (916) 322-2990, at least 45 days prior to the scheduled hearing. Copies of the Staff Report, Technical Support Document, and the text of the proposed regulation may be obtained at the above mentioned Public Information Office. Further inquiries regarding this matter should be directed to Barbara Cook, Substance Evaluation Section, Toxic Air Contaminant Identification Branch, Stationary Source Division, P.0. Box 2815, Sacramento, California 95812. Barbara Cook can be reached by phone at (916) 327-5625. CTL018876 COSTS TO PUBLIC AGENCIES AND TO BUSINESSES AND PERSONS AFFECTED The identification of vinyl chloride as a toxic air contaminant is not expected to result in any economic impacts. Economic impacts identified with respect to any specific control measures which may be developed in the future pursuant to Health and Safety Code sections 39665 and 39666 will be addressed in connection with the consideration of such measures. The Board's Executive Officer determined that the proposed action will not create costs or savings, as defined in Government Code section 11346.5(a) (6), to any state agency or in federal funding in the state, costs or mandate to any local agency or school district whether or not reimbursable by the state under Part 7 (commencing with section 17500) of Division 4 of the Government Code, or other nondiscretionary savings to local agencies. In developing the proposal, the staff considered the potential cost impact of the proposed action on directly affected private persons or businesses. As indicated above, the Executive Officer expects that the regulatory proposal would not cause any significant increased costs for such persons or businesses. The Executive Officer has determined that the proposed action will not have a significant adverse economic impact on small businesses. In addition, the Board must determine that no alternative considered by the Board would be more effective in carrying out the purpose for which the regulating action is proposed or would be as effective and less burdensome to affected private persons than the proposed action. SUBMITTAL OF COMMENTS The public may present oral or written comments relating to this matter. To be considered by the Board, written comments must be addressed to and received by the Board Secretary, P.0. Box 2815, Sacramento, California 95812, no later than 12:00 noon, December 12, 1990, or received by the Board Secretary at the hearing. The Board requests, but does not require, that 20 copies of any written statement be submitted and that all written statements be filed at least 10 days prior to the hearing. The Board encourages members of the public to bring to the attention of the staff, in advance of the hearing, any suggestions for modification of the proposed regulations. STATUTORY AUTHORITY AND HEARING PROCEDURES This regulatory amendment is proposed under the authority granted in sections 39600, 39601, and 39662 of the Health and Safety Code. The regulation is proposed to implement, interpret, or make specific sections 39650, 39660, 39661 and 39662 of the Health and Safety Code. The public hearing will be conducted in accordance with the California Administrative Procedure Act, Title 2, Division 3, Part 1, Chapter 3.5, section 11340 et seq. of the Government Code. CTL018877 Following the public hearing, the Board may adopt the regulatory amendment as proposed or with nonsubstantial or grammatical modifications. The Board may also adopt the proposed regulatory action with other modifications if the regulatory action, as modified, is sufficiently related to the originally proposed text that the public has been adequately placed on notice that the regulatory action as modified could result from the proposed regulatory action. In such an event, the full text of the regulatory action with the modifications clearly indicated will be made available to the public, for written comment, at least 15 days before it is adopted, and may be obtained from the Board's Public Information Office, 1102 Q Street, Sacramento, California 95814, (916) 322-2990. CALIFORNIA AIR RESOURCES BOARD Date: October 16, 1990 uaines u. ooya Executive Officer CTL018878 STAFF REPORT/EXECUTIVE SUMMARY PROPOSED IDENTIFICATION OF VINYL CHLORIDE AS A TOXIC AIR CONTAMINANT Prepared by the Staffs of the Air Resources Board and the Department of Health Services October 1990 CTL018879 What is a toxic air contaminant? According to section 39655 of the California Health and Safety Code, a toxic air contaminant is "an air pollutant which may cause or contribute to an increase in mortality or an increase in serious illness, or which may pose a present or potential hazard to human health." In addition, "substances which have been identified as hazardous air pollutants pursuant to Section 7412 of Title 42 of the United States Code shall be identified by the state board as toxic air contaminants." What is vinyl chloride? Vinyl chloride is a readily flammable, sweet smelling, colorless gas at ambient temperature and pressure. Because vinyl chloride polymerizes in ultraviolet light or the presence of a catalyst, the monomer of this highly volatile compound is used in the commercial production of polyvinyl chloride (PVC). HH \ C! Vinyl Chloride Monomer CTL018880 Does the Air Resources Board (ARB) staff reconreend Identification of vinyl chloride as a toxic air contaminant? Yes, the ARB staff recommends that the Board adopt the proposed amendment to section 9300, Titles 17 and 26 of the California Code of Regulations identifying vinyl chloride as a toxic air contaminant because: .0 there is sufficient evidence that exposure to vinyl chloride poses a public health hazard, o vinyl chloride is detected in ambient and indoor air near known emission sources and does not break down in the atmosphere at a rate that would eliminate public exposure, o vinyl chloride is listed as a hazardous air pollutant by the .federal government pursuant to section 7412 of Title 42 of the United States Code; therefore, pursuant to section 39655 of the California Health and Safety Code, vinyl chloride is required to be identified as a toxic air contaminant, and o the Department of Health Services (DHS) staff recommends that vinyl chloride be identified as a toxic air contaminant and that vinyl chloride be treated as having no threshold exposure level below which no significant adverse health impacts are anticipated. Why does the ARB staff recoimend the identification of vinyl chloride as a toxic air contaminant when a State ambient air quality standard already exists? The State ambient air quality standard of 10 ppbv averaged over 24 hours reflects the limit of detection (LOD) for vinyl chloride ambient air concentration analysis in 1978 when the standard was promulgated (the method CTL018881 -2- for calculating the LOD Is discussed in Section A, Chapter III, Part A, of the Technical Support Document). This technology-based standard was developed in response to information which associated the development of cancer in humans with vinyl chloride exposure and is not currently recognized as health-protective. The identification of vinyl chloride as a toxic air contaminant would allow health-protective control measures to be implemented at concentrations below 10 ppbv. What evidence exists that exposure to vinyl chloride poses a public health hazard? Acute exposure to vinyl chloride has lead to narcosis, cardiovascular and respiratory irregularity, convulsions, cyanosis, and death. Chronic exposure of workers to vinyl chloride has induced acro-steolysis, vasospasm of the hands, dermatitis, circulatory and central nervous system alterations, thrombocytopenia, splenomegaly, and changes in liver function. However, these noncarcinogenic effects occur at vinyl chloride concentrations near or above 10 ppmv. Because vinyl chloride has never been detected in samples collected from the ARB's 20-station ambient toxic air contaminant network and measured ambient hot spot concentrations range from 10 to 15 ppbv, the California Department of Health Services (DHS) staff do not expect noncarcinogenic adverse health effects from exposures to current concentrations of vinyl chloride found in ambient air. The International Agency for Research on Cancer (IARC) lists vinyl chloride in Group 1 of its carcinogen classification scheme. The United States Environmental Protection Agency (EPA) lists vinyl chloride in Group A of its carcinogen classification scheme. The IARC, the EPA, and the DHS have designated vinyl chloride a chemical for which there is sufficient evidence of carcinogenicity in both humans and experimental animals. Epidemiological studies of occupationally exposed human workers have linked vinyl chloride exposure to the development of a rare cancer, liver angiosarcoma, and have suggested a relationship between exposure and cancers of the lung and brain. Chronic inhalation and oral exposures of rats, mice. -3- cTL018882 and' hamsters to vinyl chloride have been associated with an increased incidence of malignant and benign tumors at several sites including the liver, lungs, mammary glands, and the nervous system. Vinyl chloride is mutagenic in both prokaryotic and eukaryotic test systems. Is there a threshold level for vinyl chloride? Since vinyl chloride is carcinogenic and mutagenic and there is not sufficient evidence at this time to support the designation of an exposure level below which no significant adverse health impacts are anticipated, the DHS staff recommend that vinyl chloride be treated as having no threshold exposure level. Is vinyl chloride produced or used in California? Vinyl chloride is not produced in California, however, it is estimated that several thousand tons are used each year by two facilities producing polyvinyl chloride.* Polyvinyl chloride is used by fabricators for the production of materials employed by the construction, packaging, electrical, and transportation industries. What are the sources of vinyl chloride emissions? Landfills, publicly-owned treatment works (POTWs), and polyvinyl chloride (PVC) production and fabrication facilities are the major identified sources of vinyl chloride emissions in California. ' In 1987, section 41805.5 of the California Health and Safety Code required the testing of landfills for specified compounds Including vinyl chloride. The data gathered in the Landfill Gas Testing Program will be CTL018883 -4- used by air pollution control districts to provide a relative ranking of the sites based on the potential for emissions of toxic compounds and the potential for exposure. The data show that vinyl chloride concentrations ranging from a detection limit (the Testing Guidelines example method for calculating the detection limit is discussed in Chapter II, Part A of the Technical Support Document) of 106 ppbv to 72,000 ppbv were detected in the internal gas of 160 (47 percent) out of the 340 landfills at which internal gas testing was conducted. The presence of vinyl chloride in internal landfill gas represents a potential source of vinyl chloride emissions. The South Coast Air Quality Management District (SCAQMD) conducted long-term, intensive ambient vinyl chloride monitoring on two landfills in the South Coast Area Basin (SCAB): Operating Industries Incorporated (Oil) Landfill and BKK Landfill. Oil Landfill is located near Monterey Park, California and BKK Landfill is located near West Covina, California. The test data for the Oil Landfill was obtained from January 1986 through December 1986, while data for the BKK Landfill was obtained from January 1987 through December 1987. Based.on 24-hour averaged ambient data from these testing periods, cumulative vinyl chloride emissions were estimated to range from 50 to 250 tons per year. The vinyl chloride emissions of Oil and BKK are not likely to be typical of other California landfills. However, monitoring required by the Landfill Gas Testing Program mentioned above showed 24-hour averaged ambient vinyl chloride concentrations ranging from the detection limit (the Testing Guidelines example method for calculating the L0D is discussed in Chapter II, Part A of the Technical Support Document) of 2 ppbv to 15 ppbv-at 24 (10 percent) out of the 251 landfills tested for ambient concentrations. Since the SCAQMD's study, the vinyl chloride emissions at Oil and BKK landfills are expected to have decreased because subsequent ambient levels in perimeter monitoring samples were typically below the detection limit in the late 1980's. This decrease in ambient vinyl chloride concentrations near the landfills Is attributed to the installation of gas collectors and flares. CTL018884 -5- POTWs emitted an estimated 1.7 tons of vinyl chloride in 1985. PVC production facilities emitted less than 0.5 tons of vinyl chloride in 1988 while PVC fabrication facilities emitted an estimated 0.75 tons of vinyl chloride in 1982. What is the persistence of vinyl chloride in the atmosphere? Vinyl chloride is estimated to be degraded in 1.6 to 3.9 days through its reaction with hydroxyl radicals in the atmosphere. Therefore, vinyl chloride is sufficiently persistent to be transported throughout an air basin .before it is degraded. What is the ambient concentration of vinyl chloride? Vinyl chloride has never been detected in samples collected at the 20 monitoring stations of the ARB's ambient toxic air contaminant monitoring network. Since detectable levels in California are limited to locations near identified emission sources such as landfills, vinyl chloride exposure poses a potential near-source risk rather than a statewide risk. The monitoring required by the Landfill Gas Testing Program (section 41805.5 of the California Health and Safety Code effective in 1987) showed 24-hour average ambient vinyl chloride concentrations ranging from the detection limit (the Testing Guidelines example, method for calculating the LOD is discussed in Chapter II, Part A of the Technical Support Document) of 2 ppbv to 15 ppbv at 24 out of 251 landfills tested for ambient concentrations. The South Coast Air Quality Management District (SCAQMD) obtained vinyl chloride ambient monitoring from locations near two landfills in the South CTL018885 -6- Coast Air Basin. The LOD for the SCAQMO vinyl chloride monitoring study was 2 ppbv (the SCAQMD's method for calculating the LOO is discussed in Chapter III, Part A of the Technical Support Document). At the Oil Landfill from January through December of 1986, 24-hour average concentrations of vinyl chloride ranged from below the LOD to 9.8 ppbv with a mean of 1.0 to 2.0 ppbv. The U.S. Environmental Protection Agency (EPA) states, "The Operating Industries, Incorporated (Oil) Landfill is currently a federally listed Superfund site. Subsequent to the SCAQMD's vinyl chloride sampling during 1986, the Environmental Protection Agency (EPA) has implemented more stringent landfill gas control measures. The EPA has also selected a remedy for landfill gas control that is expected to substantially reduce landfill gas emissions from the Oil Landfill. It is fully anticipated that these control measures will substantially lower the levels of vinyl chloride in the ambient air in the vicinity of the Oil Landfill." At the BKK Landfill from January through December of 1987, 24-hour average concentrations of vinyl chloride ranged from below the LOD to 15 ppbv with a mean of 1.2 to 2.6 ppbv. What is the exposure level of people living near sources such as landfills? Population-weighted exposure estimates, based on computer modeling by the ARB staff, showed that the maximum exposed individual living near Oil Landfill was estimated to be exposed to an annual average vinyl chloride concentration ranging from 0.6 to 9 ppbv. Modeled cumulative population exposure estimates (not population-weighted) predicted that 0 to 6,000 people living close to Oil may have been exposed to annual average concentrations of at least 3 ppbv (see Table I). Population-weighted exposure results estimated that approximately four million people living within about 25 square miles of Oil Landfill may have been exposed to estimated annual average vinyl chloride concentrations ranging from 0.004 to 0.06 ppbv in 1986. CTL018886 -7- TABLE I RANGE OF CUMULATIVE POPULATION EXPOSED TO VINYL CHLORIDE NEAR Oil Range of Cumulative Population Lower-bound Estimate* Upper-bound Estimate*1 Exposed to Vinyl Chloride Concentrations (ppbv) at or above: 4,287,300 272,000 33,000 12,000 0 0 0 0 4,287,300 3,111,000 1,073,000 445,000 22,000 12,000 6,000 6,000 >0 but <0.01' 0.01 0.05 0.10 1.0 1.5 2.0 3.0 a - The exposure estimate is based on an emission rate of 0.31 ug/m? s 1 . b - The exposure estimate is based on an emission rate of 4.42 ug/m2 s i . c - According to the model, the entire cumulative population studied was at least exposed to vinyl chloride concentrations between -0 and less than 0.01 ppbv. In addition, calculated population-weighted exposure for this population was estimated to range from an annual average of 0.004 to 0.06 ppbv vinyl chloride. For the BKK Landfill, the population-weighted exposure results showed that the maximum exposed individual living near BKK was estimated to be exposed to an average annual concentration of 2 to 10 ppbv. Modeled cumulative population exposure estimates (not population-weighted) predicted that 0 to 2,500 people living close to BKK may have been exposed -8- to annual average concentrations of at least 7 ppbv (see*Table II). Population-weighted exposure results estimated that approximately two million people living within about 25 square miles of BKK Landfill may have been exposed to annual average vinyl chloride concentrations ranging from 0.08 to 0.34 ppbv in 1987. TABLE .II RANGE OF CUMULATIVE POPULATION EXPOSED TO YINYL CHLORIDE NEAR BKK Range of Cumulative Population Lower-bound Estimate3 Upper-bound Estimate11 Exposed to Vinyl Chloride Concentrations (ppbv) at or above: 2,154,000 2,026,000 732.000 374,000 17,000 0 0 0 0 0 0 2,154,000 2,154,000 1,970,000 1,431,000 131,000 54,000 28,000 20,000 14,000 7,000 2,500 >0 but <0.01c 0.01 0.05 0.1 1.0 2.0 3.0 4.0 5.0 6.0 7.0 a - The exposure estimate Is based on an emission rate of 0.75 ug/m^s~*. b - The exposure estimate is based on an emission rate of 3.32 ug/m^s"*. c - According to. the model, the entire populationwas at least exposed to vinyl chloride concentrations between 0 and 0.01 ppbv. In addition, the calculated population-weighted exposure for this population was estimated to range from an annual average of 0.08 to 0.34 ppbv vinyl chloride. -9CTLOISSSS These exposure estimates are based on ambient data only and do not include any possible elevated indoor exposures that may occur inside homes near landfills. Is there evidence of indoor air exposure to vinyl chloride? In California, vinyl chloride in indoor air has been detected only in houses near landfills. In 1985, a South Coast Air Quality Management District (SCAQMD) indoor air grab-sample study showed vinyl chloride concentrations ranging from 8 to 100 ppbv in some homes near Oil Landfill. Present indoor vinyl chloride concentrations in- the residences near Oil are believed to be lower due to Oil's installation of gas collectors and flares subsequent to the SCAQMD study. In order to test this idea, additional indoor air monitoring at homes adjacent to the' landfill is being considered. To date, no indoor vinyl chloride has been detected in studies of homes not located near landfills. Are there other routes of exposure to vinyl chloride? Exposure to vinyl chloride may also occur from ingestion of food and water that contain residues of the substance. Prior to 1975, vinyl chloride monomer levels as high as 20 ppmw were found in food packaged in vinyl chloride polymer containers or materials. In 1986, the Food and Drug Administration (FDA) proposed to limit the maximum amount of residual vinyl chloride monomer in rigid and semi-rigid food containers to 10 ppbw and the maximum amount of vinyl chloride monomer allowed in polymeric coatings and films which contact food to 5 ppbw. According to an FDA official, the regulation was not promulgated because it was believed that monomer stripping processes leave no residue of vinyl chloride monomer. An estimate of the potential for vinyl chloride exposure from food ingestion is not possible because, to our knowledge, current -10- CTL018889 information on the levels in food and food packaging is not available. The vinyl chloride exposure estimates in this Staff Report/Executive Summary and in the accompanying Technical Support Document do not account for potential exposure from polymeric food packaging. In California, surface water and ground water from public water systems are generally free of vinyl chloride. Since it is not typically detected in drinking water, exposure through this route is not expected to significantly contribute to the cancer burden attributed to vinyl chloride. What is the risk assessment for exposure to vinyl chloride? The DHS analyzed many human occupational and animal studies in the cancer risk assessment for vinyl chloride exposure. Predictions from the majority of the studies of humans exposed to vinyl chloride occupationally are uncertain due to inadequate exposure data, insufficient follow-up time, and methodological problems. Based on the exposure estimates for vinyl chloride workers in the Waxweiler, et al. (1976) study, the 95i upper confidence limit on the lifetime unit risk of contracting cancer from vinyl chloride ranged from 2.5 x 10"5ppb-1 to 4.5 x 10"5ppb~*. Evaluation of animal experiments using the linearized multistage model leads to predictions of upper confidence limits on unit risks for humans ranging from 3.7 x 10 -5 ppb-1 to 20 x 10-5pp-b1 . Considering tumorgenicity data as well as the results of human and animal studies, the DHS staff conclude that the overall range of upper confidence limits on cancer unit risk is 2.5 x 10'^ppb"* to 20 x 10_ppb"*. In order to ensure protection of public health, the DHS has identified the best estimate of cancer unit risk to be 20 x 10-5ppb-1, the top of the upper confidence limits range. Using the best estimate of cancer unit risk, an estimated 200 cancers may occur in one million people exposed to 1 ppbv of vinyl chloride for a 70-year lifetime. Because vinyl chloride has not been detected 4n statewide ambient air monitoring, 24-hour averaged hot spot concentrations detected by monitors -11- CTL018890 near two South Coast landfills were used in a model to estimate annual average outdoor concentrations and to assess the probable impact of vinyl chloride on the cancer burden for people living near these landfills. Population-weighted modeled estimates of peak exposure concentrations for maximally exposed receptors ranged from 0.6 to 9 ppbv at the Oil Landfill and from 2 to 10 ppbv at the BKK Landfill. An estimated 17,000 to 131,000 persons were exposed to 1 ppbv of vinyl chloride near the BKK Landfill where the highest exposures were predicted from the monitoring results of 1987. Using the upper confidence limits range of risks, the DHS estimated that 3 to 36 cancers may occur in 131,000 persons due to lifetime exposure to 1 ppbv of vinyl chloride. All of the above estimates represent the upper range of plausible excess cancer risk. Estimates of actual risks could be much lower. What are the alternatives to identifying vinyl chloride as a TAG? California Government Code section 11346.14 requires agencies to describe alternatives to the regulation considered by the agency and the agency's reasons for rejecting those alternatives. The only alternative to identifying vinyl chloride is not to identify it. We are not recommending this alternative because we believe that vinyl chloride meets the definition of a toxic air contaminant and because vinyl chloride is Ifsted as a hazardous air pollutant by the federal government pursuant to section 7412 of Title 42 of the United States Code; therefore, pursuant to section 39655, vinyl chloride is required to be identified as a toxic air contaminant. What would be the environmental Impact of the identification of vinyl chloride as a toxic air contaminant? The identification of vinyl chloride as a toxic air contaminant is not itself expected to result in any impact on the environment. -12- CTL018891 The Board's identification of vinyl chloride as a toxic air contaminant may result in the adoption of control measures according to the California Health and Safety Code sections 39665 and 39666. Subsequent to identification, the implementation of control measures would benefit the public health by reducing vinyl chloride emissions resulting in a reduced health risk due to vinyl chloride exposure. Environmental impacts identified with respect to specific control measures will be included in the consideration of such control measures pursuant to the California Health and Safety Code sections 39665 and 39666. What are the findings of the Scientific Review Panel? In accordance with California Health and Safety Code Section 39661, the Scientific Review Panel (SRP) has reviewed the report prepared by the staffs of the Air Resources Board (ARB) and the Department of Health Services (DHS) on the public exposure to, and health effects of vinyl chloride. The Panel has also .reviewed the public comments received on this report. Based on this review, the SRP finds that the report on vinyl chloride is without serious deficiencies and agrees with the staffs of the ARB and the DHS that: 1. There is strong evidence that exposure to vinyl chloride results in animal and human carcinogenicity. The United States Environmental Protection Agency (USEPA) assigned vinyl chloride to Group A of its classification scheme for carcinogens. In explaining its Group A category, the EPA states, "This group is used only when there is sufficient evidence from epidemiologic studies to support a causal association between exposure to the agents and cancer." The International Agency for Research on Cancer (IARC) assigned vinyl chloride to Group 1 of its classification scheme for carcinogens. In introducing its list of Group 1 carcinogens which included vinyl chloride, the IARC states, "The Working Group concluded that the -13- CTL018892 following agents are carcinogenic to humans." Based on available scientific data, the Panel agrees with the EPA's and the IARC's classification of vinyl chloride as a human carcinogen. Based on available scientific information, the DHS staff found no evidence of a vinyl chloride exposure level below which no carcinogenic effects are anticipated. Based on the interpretation of available scientific evidence, the DHS staff estimated that the upper 95 percent confidence limits on the lifetime risk of cancer from vinyl chloride ranged from 2.5 x 10"** ppb~* to 20 x 10"5ppb"1. The DHS staff'identified the best estimate of vinyl chloride cancer unit risk as the top of the upper confidence limits range, 20 x 10"5ppb"1 or 7.8 x 10"5(ug/m3)-1. Table III compares the best estimate of vinyl chloride cancer unit risk with those of other compounds recently reviewed by the SRP. Compound Vinyl chloride Chloroform Trichloroethylene Inorganic arsenic Methylene chloride TABLE III Unit Risk foob'1! 20 x 10"5 2.6 x 10"5 1.1 x 10'5 particulate 3.5 x 10"6 Unit Risk fuq/m3!"1 7.8 x 10'5 5.3 x 10"6 2 x 10"6 3.3 x 10"3 1 x 10"6 Upper bound excess lifetime risks are health-protective estimates; the actual risk may well be below these values. Landfills, publicly-owned treatment works, and polyvinyl chloride producers and fabricators are the major Identified sources of vinyl chloride emissions in California's outdoor air. Based on its gas-phase reactivity with hydroxyl radicals, vinyl chloride's estimated tropospheric lifetime ranges from 1.6 to 3.9 days. -14- CTL018893 6. Vinyl chloride has not been detected by the ARB's statewide ambient toxic air contaminant monitoring network. However, vinyl chloride has been detected in the ambient air near emission sources such as landfills. 7. The limited monitoring conducted in the Landfill Gas Testing Program which began in 1987 was designed to identify landfill sites that pose a potential risk to public health. Preliminary findings show that vinyl chloride concentrations ranging from the detection limit of 106 ppbv to 72,000 ppbv were detected in the internal gas of 160 (47 percent) out of the 340 landfills at which internal gas testing was performed. 24hour averaged ambient vinyl chloride concentrations ranging from the detection limit of 2 ppbv to 15 ppbv were detected at 24 (10 percent) out of the 251 landfills at which ambient monitoring was performed. The limited testing conducted was designed to be used for screening purposes. For that reason, vinyl chloride may be present in the ambient air at additional landfills, but was not detected in the one to three days of'ambient testing specified in the testing guidelines for the Program. Further interpretation of the data from specific landfill sites must also consider factors such as how the testing was carried out, along with, location, size, and proximity to sensitive receptors. 8. Ambient vinyl chloride data from perimeter monitoring by the South Coast Air Quality Management District (SCAQMD) at two landfills in 1986 and 1987 were used in a model to estimate population-weighted exposures near the sites. These exposure estimates were based on ambient outdoor data and do not include any possible elevated indoor exposures that may occur inside homes near the landfills. The cancer risk from vinyl chloride exposure to people residing in the vicinity of the landfills may be determined using the DHS's best estimate of vinyl chloride cancer unit risk of 20 x 10 -5 ppb-1 (see Finding 3 above) and the modeled population-weighted exposure estimates. -15- CTL018894 a. Population-weighted exposure for maximally exposed individuals living immediately adjacent to the landfills (at the fenceline) was estimated to range from an annual average of approximately 0.6 to 9 ppbv vinyl chloride at Oil Landfill and from approximately 2 to 10 ppbv at BKK Landfill. b. Modeled estimates of exposure (not population-weighted) for 0 to 6,000 people living close to Oil and for 0 to 2,500 people living close to BKK are included to provide an idea of the predicted exposure levels and risk directly downwind from the landfills. According to the model, 0 to 6,000 people near Oil may have been exposed to annual average vinyl chloride concentrations of at least 3 ppbv and 0 to 2,500 people near BKK may have been exposed to annual average concentrations of at least 7 ppbv. Using the DHS's best estimate of cancer unit risk, 0 to 4 or more cancers were estimated to occur among the 6,000 people living closest to Oil; and 0 to 4 or more cancers were estimated to occur among the 2,500 people living closest to BKK. c. Population-weighted exposure results were calculated for the people living within a 41 square-kilometer area (or, approximately 25 square-mile area) of each landfill. For Oil Landfill, approximately 4 million people may have been exposed to average annual concentrations ranging from 0.004 to 0.06 ppbv. For BKK Landfill, approximately 2 million people may have been exposed to annual average concentrations ranging from 0.08 to 0.34 ppbv. Using the DHS's best estimate of cancer unit risk, 4 to 48 cancers were estimated for the 4 million people living within approximately 25 square miles of Oil; and 32 to 136 cancers were estimated for the 2 million people living within approximately 25 square miles of BKK. The limited data available indicate that the vast majority of homes have very low, often undetectable, indoor vinyl chloride concentrations. However, grab samples collected by the South Coast Air Quality Management District (SCAQMD) in 1985 showed concentrations -16- CTL018895 ranging from 8 to 100 ppbv inside a few homes near Oil Landfill mentioned in Finding 8. Current indoor concentrations in the homes studied by the SCAQMD in 1985 are expected to be lower because of the subsequent installation of a landfill gas collection and flare system. In order to test this idea, additional indoor air monitoring at homes adjacent to the landfill is being considered. Since vinyl chloride is not typically detected in indoor air, exposure through this route is not expected to significantly contribute to overall risk, except in the vicinity of certain landfills. 10. Non-carcinogenic health effects are not known to occur at: 1) the highest recorded 24-hour average outdoor concentration in California (15 ppbv) (see Finding 7), 2) the estimated outdoor average annual vinyl chloride concentrations (see Findings 6 and 8), or 3) the highest recorded vinyl chloride concentration from the air inside a California home (100 ppbv) (see Finding 9). 11. Prior to 1975, vinyl chloride monomer levels as high as 20 ppmw were found in food packaged in vinyl chloride polymer containers or materials. In 1986, the Food and Drug Administration (FDA) proposed to limit the maximum amount.of residual vinyl chloride monomer in rigid and semi-rigid food containers to 10 ppbw and the maximum amount of vinyl chloride monomer allowed in polymeric coatings and films which contact food to 5 ppbw. According to an FDA official, the regulation was not promulgated because it was believed that monomer stripping processes leave no residue of vinyl chloride monomer. There is no further information available on the levels of vinyl chloride in food containers and packaging. The exposure estimates in Finding 8 do not account for potential exposure from polymeric food packaging. In California, surface water and ground water from public water systems are generally free of vinyl chloride. Since it is not typically -17- CTL018896 detected in drinking water, exposure through this route is not expected to significantly contribute to the cancer burden attributed to vinyl chloride. 12. Because vinyl chloride was identified as a hazardous air pollutant under Section 112 of the United States Clean Air Act, identification of vinyl chloride as a toxic air contaminant is required by California Health and Safety Code Section 39655. 13. Based on all available scientific evidence, including consistent animal and human studies and the small range of dose extrapolation (from the animal studies), we conclude that the data are overwhelming that vinyl chloride is a toxic air contaminant. We agree with the ARB staff recommendation to its Board that vinyl chloride be listed as a toxic air contaminant. -18- CTL018897 Dnniamo< Cftemtatry end ttccft--Mony-- (7U) 775-36*1- CaJHomi.tu>iUttfrftrr fuilttow-- Fvdt--ton? CaUlmi-- U Correspondence to P.0, Box 661 8n Clemente. CA 92674*669 Phone: (7H> 361.1132 FAX: {711 361.1263 October 22. 1990 Hr. William C. Lcckett, Chief Office of External Affairs California Air Resources Board 1102 Q Street Sacramento, California 95814 Dear Sill: The Scientific Review Panel on Toxic Air Contaminants has reviewed the Resort on Vinyl. Chloride and has formulated its findings regarding the report. I am formally submitting the Scientific Review Panel's findings to the Air Resources Board. Sincerely, Enclosure cc: Scientific Review Panel Dr. James H. Pitts. Jr. Chair, Scientific Review Panel CTL018898 Scientific Cavity Fw) FlmHng on the &22_ As Adopted at the Panel's October 13, 1990 Meeting -In-accordance with California Health and Safety Cede Section 39661. the Scientific Review Panel (SRP) has reviewed the report- prepared by the staffs cf the Air Resources Board (ARB) and the Department of Health Services (DHS) on the public exposure to, and health effects of vinyl chloride. The Panel has also reviewed the public comment* received on this report. Based cn . this review, the SRP finds that the report on vinyl chloride is without serious deficiencies and agrees with the staffs of the ARB and the DHS that: 1. There Is strong evidence that exposure to vinyl chloride results In animal and human carclnoganlclty. The Unltad States Environmental Protection Agency (USEPA) assigned Ylnyl chloride to Group A of Its classification scheme for carcinogens. In explaining Its Group A cstegcry, the EPA states. "This group Is used only when there is sufficient evidence from epidemiologic studlee to support a causal association between exposure to the agents and cancer." The International Agency for Research on Cancer (IARC) assigned vinyl chloride to Group 1 cf Its classification scheme fer carcinogens. In introducing Its list of Group 1 carcinogen* which Included vinyl chloride, the IARC stats*, "The Porting Group concluded, that the following agents ire carcinogenic to humane." Based en available scientific data, the Panel agree* with the EPA's and the IARC's classification of vinyl chloride a* a human carcinogen.2 2. Sased oa available scientific Information, the DHS staff found no `evidence of a Ylnyl chloride txposurt level below which no carcinogenic effects are anticipated. CTL018899 I 3. cased cn the interpretation of available scientific evidence, the OHS staff estimated that the upper 95 percent confidence limits on the lifetime risk of canter from Ylnyl chloride ranged from-2.S x 10' ppb"1 to 20 x 10'*ppb"l. The OHS staff Identified the best estimate of vinyl chloride cancer unit risk as the tcp of the upper-confidence limits range, 20 x 10"5ppb"1 or 7.8 x 10*5(ug/ra3)'*. Table 1 compares the best estimate of vinyl chloride cancer unit risk with those of other compound* recently reviewed by the SRP. Compound TABLE 1 Unit Risk fece"M Unit Risk fuc/rr?)"1 Vinyl chloride Chloroform Trichloroethylene Inorganic arsenic Methylene chloride 20 x IQ'5 2.6 x 10`5 1.1 x IQ*5 particulate 3.5 x 10** 7.8 x 10_S 5.3 x 10*6 2 x 10'* 3.3 x 10`3 1 x 10** 'Jooer bound excess lifetime risks are health-protective estimates; the actual risk may wall be below these values. .anafiiis, publicly-owned treatment wonts, and polyvinyl chloride crcdueert and fabricators art the major identified sources of ylnyl chloride emissions In California's outdoor air. Up 3ased on Its gas-phase reactivity with hydroxyl radicals, vinyl chloride's estimated tropospheric lifetime ranges from l.S to 3.9 days.9 9. Vinyl chloride has not bea'n detected by the ARB's statewide ambient toxic air contaminant monitoring natvork. However, vinyl chloride has been detected In the ambient air near amission sources such as landfills. CTL018900 ?. The United monitoring conducted In the landfill Gas Testing Program which began in 1987 was designed to Identify landfill sites that pose a potential risk to public health. Preliminary findings show that vinyl chloride concentrations ranging from the detection limit of 106 ppbv to 72,000 ppbv were detected In the Internal gas of 180 (47 percent) cut of the 340 landfills at which Internal gas testing was performed. 24hour averaged ambient vinyl chleride-concentratlone ranging from the detection limit of 2 ppbv to 15 ppbv were detected at 24 (10 percent) out of the 251 landfills at which ambient monitoring was performed. The limited testing conducted was designed to be used for screening purposes, For that reason, Ylnyl chloride mty be present In the amolent air at additional landfills, but wae not detected In the cr.e to three days of amolent tasting specified In the testing guidelines for the Program. Further Interpretation of ths date from specific landfill sites must also consider factors such as how the testing was carried out, along with location, slit, and proximity to sensitive receptors. g. Ambient Ylnyl chloride data from perimeter monitoring by the South Coast Air Quality Management District (SCAQMO) at two landfills In 1SSS and 1987 were used In a model to estimate population-weighted exposures "8ar the sites. These exposure estimates.were based on ambient outdoor data and do not include any possible elevated indoor exposures that may occur inside homes near the lanofllls. The cancer risk from vinyl chloride exposure to people residing In the vicinity of the landfills may be determined using the OHS'* best estimate of vinyl chloride cancer unit risk of 20 x 10-oppb*1(see Finding 3 above) and the meceled population-weighted exposure estimates. a. Population-weighted exposure for maximally exposed Individuals living Immediately adjacent to the landfills (at the fenceline) wes estimated to range from an annual average of approximately 0.8 to 9 ppbv vinyl chloride at Oil Landfill and from approximately 2 to 10 ppbv at BKK Landfill. CTli0l89Ql b, Modeled estimates of exposure (not population-weighted) for 0 to $,000 people living .close to Oil and for 0 to 2,500 paopla living dost to BBC art Included to provide an 1da of tha predicted exposure levels and risk directly downwind from tha landfills. According to the model, 0 to 6,000 people-near Oil may have been xpcsed to annual average vinyl chloride concentrations of at least 3 ppbv and 0 to 2,500 people near BMC may have bean exposed to annual average concentrations of at least 7 ppbv. Using the OHS'* best estimate of csncer unit risk, 0 to 4 or more csnccrs were estimated to occur among the 6,COO people living closest to Oil; and 0 to 4 or more cancers vers estimated to occur among the 2,500 people living closest to BMC. c. Population-weighted exposure results were calculated for the people living within a 41 square-kilometer area (or, approximately 25 square-mile area) of each landfill. For Oil Landfill, approximately 4 million people may have been exposed to average annual concentrations ranging from 0.004 to 0.05 ppbv. For BMC Landfill, approximately 2 million peoole may have been exposed to annual average concentrations ranging from 0.08 to 0.34 ppbv. Using the DHS's best estimate cf cancer unit risk, 4 to 48 esneers were estimated for the 4 million people living within approximately 25 square miles of Oil; and 32 to 135 cancers were estimated for the 2 million people living within approxlmetely 25 square miles of BMC. The limited data available Indicate that the vast majority of homes have very low, eftsn undetectable. Indoer vinyl chloride eonctntratlons. However, grab samples collected,by the South Coast Air Quality Management District (SCAQMD) In 1985 showed concentrations ringing frem 8 to 100 ppbv inside s few hemes near Oil Landfill mentioned in Finding 8. Current Indoor concentrations in the homes studied by tha SCAQMD In 1985 are expected to be lower because cf the subsequent Installation of a landfill gas collection and flare system. CTL018902 In order to test this idee, additional indoor air monitoring at homes adjacent to the landfill is being considered. Since vinyl chloride is not typically detected in indoor air, exposure through this route is not expected tc significantly contribute to overall risk, except in the vicinity cf certain landfill*. ^on-carcinogenic health effect* are not knovn to occur at: 1) the highest recorded 24-hour average outdoor concentration in California (15 ppbv) (see Finding 7}, 2) the estimated outdoor average annual vinyl chloride concentrations (see Findings 6 and 8), cr 3) the highest recorded vinyl chloride concentration from the air inside a California home (100 ppbv) (see Finding 9). ?r1er to 1375, vinyl chloride monomer levels as high as 20 ppmw were found in food packaged in Yinyl chloride polymer containers cr materials. In 1986, the Food and Drug Administration (FDA) proposed to limit the maximum amount of residual vinyl chloride monomer in rigid and semi-rigid food containers to 10 ppbv and the maximum amount of vinyl chloride monomer allowed In polymeric coatings and films which contact food to 5 ppbw. According to an FDA official, the regulation was net promulgated beeause it was believed that monomer stripping processes leave no residue of vinyl chloride monomer. There Is no further Information available on the levels of vinyl chloride In food containers and packaging. The exposure estimates in Finding 8 do net account for potential" exposure from polymeric food peekaging. In California, surface water and ground water from public water systems are generally free of vinyl chloride. Since it Is not typically detected In drinking water, exposure through this rout Is not expected to significantly contribute to the cancer burden attributed to vinyl chloride. CTL018903 12. 3eeausa vinyl chloride was Identified as t hazardous air pollutant undar Section 112 of tha United Statas Clean Air Act, Identification of vinyl chloride as a toxic air contaminant Is required by California Health and Safety Code Section 39655. 13. Sated on all available scientific evidence. Including consistent animal and human studies and the snail range of dose extrapolation (from the animal studies), we conclude that the data are overwhelming that vinyl chloride Is a toxic air contaminant. We egrea with the ARB staff racoimjendation to Its Board that vinyl chloride st listed si a toxic air contaminant. I certify that the above is a true and correct copy of the findings adoptsd by the Scientific Revlev Panel on Oetcber 19. 1990. TL0l8904