Document np5bbpbkQq3Xyzje95q0o0bMz

A mmm Vinyl W m Institute A Division of The Society of The Plastics Industry, Inc. lPC& November 5, 1990 TO: Health, Safety and Environment Committee RE: CARB Hearings on Vinvl 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 SPl-05543 Wayne Interchange Plaza II 155 Route 46 West Wayne, NJ 07470 (201) 890-9299 Fax (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: PLACE: 9:30 AM 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., December 13, 1990 and will continue at 8:30 a.m., December 14, 1990. Please consult the hearing agenda (available at least ID 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 OHS staff also found that there was not sufficient scientific evidence to SPI-05544 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 PERSON 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 summarizes 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 Vinyl Chloride," prepared by the Board staff; Part B, "Health Effects of Airborne Vinyl Chloride," prepared by the DHS; and Part C, "Staff Responses to Public Comments on the Vinyl 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 8ranch, Stationary Source Division, P.0. Box 2815, Sacramento, California 95812. Barbara Cook can be reached by phone at (916) 327-5625. SPI-05545 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. SPI-05546 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 James u. ooya Executive Officer SPI-05547 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 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). H \ C / H H Cl Vinyl Chloride Monomer SPI-05549 for calculating the LOO 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 (OHS) 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, -3SP1-05550 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 ppbvat 24 (10 percent) out of the 251 landfills tested for ambient concentrations. Since the SCAQMD's study, the vinyl chloride emissions at QII 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. -5- SPI-05551 Coast Air Basin. The LOD for the SCAQMD vinyl chloride monitoring study was 2 ppbv (the SCAQMD'$ method for calculating the LOD is discussed in Chapter III, Part A of the Technical Support Oocument). 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 011 Landfill may have been exposed to estimated annual average vinyl chloride concentrations ranging from 0.004 to 0.06 ppbv in 1986. -7SPI-05552 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 VINYL CHLORIDE NEAR BKK Range of Cumulative Population Lower-bound Estimate9 Upper-bound Estimate19 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/m2 s -1 . b - The exposure estimate is based on an emission rate of 3.32 ug/m2 s -1 . c - According to the model, the entire population was 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. -9SPl-05553 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 95t upper confidence limit on the lifetime unit risk of contracting cancer from vinyl chloride ranged from 2.5 x 10_!*ppb"* to 4.5 x lO^ppb"1. 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'^ppb-* to 20 x 10"ppb"^. 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 -5 ppb -l , 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 -in statewide ambient air monitoring, 24-hour averaged hot spot concentrations detected by monitors -11- SPI-05554 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 8oard (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- SP1-05555 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"ppb"*(see Finding 3 above) and the modeled population-weighted exposure estimates. -15- SPI-05556 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 Orug 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 -17SPl-05557 ClIlfCNnlKflMKkiBlWflifVrPUllMtfil^' Oitenmowi 8 cnminryand Heal--wr- (714) 77%satr Carrtspondtne* to: p.o. see eat sen ctameme. CA 92t7*et Phone: (714) 341.1132 PAX: (714) dtl.1213 October 22. 1990 Mr. William C. Lockett. Chief Office of External Affairs California Air Resources Board 1102 Q Street Sacramento. California 95914 Dear Sill: The Scientific Review Panel on Toxic Air Contaminants has reviewed the Report on Vinyl Chloride and has formulattd its findings regarding the report. 1 am formally submitting the Scientific Review Panel's findings to the Air Resources 8oard. Sincerely Erie I osure cc: Scientific Review Panel Dr. James H. Pitts. Jr. Chair, Scientific Review Panel SPI-05558 tMortifle Review >wl Flwdlnge nn tho CMopSdo - As Adopted it the Panel's October-19, 1330 Martin? -In -accordance with Califomit Health and Safety Code Section 39661* tho Scltntif 1c Review Panol (SRP) has reviewed th report prepared by tho staffs of the Air Resources Board (ARB) and tho Department of Health Sarvicas (CHS) on the public exposure to* and health affects of vinyl chloride. The Panel has also reviewed the public cements 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 OHS that: 1. There Is strong evidence that txoosure to vinyl chloride results in animal and human carcinogenicity. The United States Environmental 'rotectlon Agency (USEPA) assignee vinyl chloride to Group A of its classification seheme for carcinogens. In explaining Its Group A csttgery, 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 Ageney for Research on Cancer (IARC) assigned vinyl chloride to Group 1 of Its classification schema for carcinogens. In introducing its list of Group 1 carcinogens which Included vinyl chloride, the IARC states, "The Working Group coneludad. that the following agents are carcinogenic to humans." Based on available scientific data* the Panel agrees with the EPA't and the lARC's classification of vinyl chloride as human carcinogen. Z. 3aaed on available scientific Information, the OHS staff found no evidence of a vinyl chloride exposure level balev which no carcinogenic effects are anticipated. SPI-05559 The '4,m 11bd monitoring conducted In tha Landfill Sis Testing Program wnich began tn 1987 wee designed to identify landfill sites that pose a potential risk to pub lie health. Preliminary findings shew that vinyl chloride concentrations ranging from the detection limit of 106 ppbv to 72.000 ppbv wtr 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 IS ppbv were dbtsetad at 24 (10 percent) out of the 251 landfills at which ambient monitoring wee performed. The limited tasting conducted was dastgned to be used for screening jurooses. For that reason. Ylnyl chloride may bt present in the undent air at additional landfills, but waa net detected in the one to three days of amolent testing specified in the testing guidelines for the Program. Further Interpretation of the data from sbbdflc lanaflil sites must also consider factors sueh as how the testing was carried out, along with location, sizs, and proximity to sensitive receptors. 3. Ambient vinyl chloride data from perimeter monitoring by the South Coast Air Quality Management District (SCAqMO) at two landfills in 1386 and 1987 were used In a model to estimate population-weighted exposures near the sites. Those exposure estimates.were based on ambient outdoor cats ano do not include any possible elevated Indoor exposures that may occur Inside homes near the lanafllls. The caneer risk from vinyl chloride exposure to people residing In the vicinity of the landfills may be determined using the QHS's best estimate of vinyl chloride cancer unit risk of 20 x iQ`5ppb"*(see Finding 3 above) and the moaeleo pooulation-veightaa exposure estimates. a. Population-weighted exposure for maximally exporad individuals living immediately adjacent to the landfills (at the fencellne) was estimated to range from an annual average of approximately 0.6 to 9 ppov vinyl chloride at 011 Landfill and from approximately 2 to 10 ppbv at BKk Landf111. SP1-05560 *T ^ In order to tost this Idoo. additional Indoor air monitoring at homos adjacent to tho landfill Is being considered. Since vinyl chloride Is not typically dotoetod In indoor air. exposure through this routo Is not expected tc significantly contribute to overall risk, except In the vicinity of certain landfills. Uon-carclnegenic health effects are not known to oeeur at: 1) the highest recorded 24-hour average outdoor concentration In California (IS 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). Prior to 1978, vinyl chloride monomer levels as high as 20 ppmw were found in food packaged In Yinyl chloride polymer containers or materials. In 1988, the Food and Drug Administration (FOA) proposed to limit the maximum amount of residual vinyl chloride monomer In rigid and semi-rigid food containers te 10 ppbw and the maximum amount of vinyl chloride monomer allowed In polymeric coatings and fllme which contact food to 5 ppbw. According to en FOA 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 polymerle food packaging. In California, surface water and ground water from puPHc water systama are generally free of vinyl chloride. Since it is not typically dateeted in drinking water, exposure through this route is not expected to significantly contribute to the canoer burden attributed to vinyl chloride. SPH