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01-18-1994 - Vinyl Chloride Measurement for Risk vs. Enforcement. ity of AeWilt Covina morandum To: City Manager City Council From: Environmental Services Director Subject: Vinyl Chloride Measurement t AGENDA ITEM NO. F-1 'DATE. January 1 R ] _9A for- Risk vs Enf orcemen SUMMARY:. The Waste Management and Environmental Quality Commission,. had information presented by ' the BKK Landfill Interagency Steering Committee on the emissions and measurement of vinyl. chloride at the BKK Landfill Some information was presented that addressed the difference.'between measured concentrations of vinyl chloride for Proposition 65. and. enforcement purposes. This matter was on the City Council agenda for January 4, 1994, but was carried over to this meeting. On December 16, 1993,.the Waste. Management and Environmental Quality Commission_ received the quarterly report :.from the BKK Landfill Interagency Steering Committee. The emissions of vinyl chloride from the Landfill and its relationship to air quality enforcement and.Proposition 65 was discussed. An explanation of the different purposes of Proposition 65 notification .and enforcement and the current concentration levels of vinyl chloride for these purposes was discussed. The Commission voted to recommend to the City Council that the City'' request the appropriate agencies to provide an explanation'of the different concentration levels of vinyl chloride. for Proposition 65 notification purposes vs. enforcement and other purposes.. The.recent Proposition 65 notices placed in:the newspaper by BKK Corporation caused some discussion.of the vinyl chloride emissions; at the Landfill. During the course of the regular. BKK Landfill Interagency Steering Committee report some explanations were provided. on this subject. This discussion 'may'be. summarized as follows: 1._ The permitted concentration of vinyl chloride for enforcement purposes is 10 parts per billion (ppb) . This concentration is normally only applied to businesses that use vinyl chloride in their operation and may have an emission to control. The current AQMD regulation exempts landfills.. AQMD Staff has recommended this exemption be removed. 2. The 10 ppb vinyl chloride concentration for enforcement purposes was a level established by the California Air Resources Board (CARS) in 1978. According to the State, this level was established on the ability of equipment and analysis procedures to measure this level of.'.vinyl chloride: According to the State this was the lowest concentration that could'.be consistently measured by equipment ,at the timer The AQMD is in the process of -reviewing this enforcement concentration level.. They may consider the lowering of this concentration level. 3. The 0.05 ppb vinyl chloride concentration for the United States Environmental.P,rotection Agency's risk assessment purposes is based on the.number.adopted by CARB in 1990'. This was done-asa part'of CARB's Toxic Air Contaminant Program. The California Environmental Protection Agency,. Office of 'Environmental, and Health Hazard Assessment (OEHHA) estimated the carcinogenic potency of vinyl chloride for this Program. 4. The Proposition 65 warning level is:.based on the 0.05 ppb level of concentration -of vinyl chloride in the air_. According to the State the'Proposition 65 warning level (the No Significant Risk Level) is set at 1 excess -case. of cancer in 100,00.0 exposed individuals. Using OEHHA's 7� potency value for vinyl chloride, the. Proposition 65 warning level equates to 0.05 ppb in ambient air (3 micrograms per day). According to the State this risk estimate assumes a lifetime .(70 years) exposure at this concentration. 5.. The difference between the vinyl chloride concentration used for enforcement. and that level used for the risk assessment and Proposition 65 is a factor of 200. In other words, 10 ppb concentration of vinyl chloride used for. enforcement is 200 times greater than the risk assessment level of 0.05 ppb. 6. 'In.between the extremes of.10 ppb and 0.05 ppb mentioned above is the, capability of equipment to measure these concentrations. The agencies are of the opinion that no one has the ability to consistently measure 0.05 ppb, even with the most sophisticated equipment under very controlled conditions in a laboratory. This relationship between vinyl.chloride concentrations and equipment can be visually represented as follows: .10 parts per billion AQmb enforcement concentration •---- Range in which equipment in the field may measure. vinyl chloride 0.05 parts per billion The.concentration of vinyl chloride used by the ARB for Proposition 65 based 'on cancer risk assessment 7.`The background risk of developing cancer.in our society is around.one person in a population of three. In other words,.:.one out every three persons will develop,. cancer during their lifetime. To,place this in perspective, there would be over. 33.,000 cases of cancer in a population of 100,000 that would equate to,the background risk level The above information has been.presented at different times over the last_few'years. This information' was conveyed in oral and.. written reports. However,' most of the time the information was_in a technical context that may or may not have been understood by the public. In addition,. the above informationhas never been put into.,. writing that would allow :the,public to read -the description of the various regulations and compare them .to each other It is this lack of comparison that the Waste Management and Environmental Quality Commission took their action. The Commission unanimously recommends to the City Council that the City request the appropriate agencies to provide an explanation'of the different. concentration 'levels of vinyl chloride for Proposition 65 notification purposes.vs. enforcement and other purposes. V, Staff agrees with.the Commission action. A request to the BKK ..Landfill Interagency Steering Committee should be7made to provide,_' a lay -language explanation so the public can understand the vinyl - chloride matter.` Staff would direct a letter to, the Federal Environmental Protection Agency representative.with copies to the other.. Steering Committee members Staff would request a coordinated response,on the matter.. Once received this- written information may then be provided to any. interested,resident., Staff also supports ' the-. action because it will 'relieve the City' Staff of the need to try to explain the I vinyl, chloride matter. Staff is not qualified to discuss .the matter beyond the information we have, heard or read from other :agencies. `The.` appropriate agencies should provide a coordinated response in a single document. that can be shared with the City and public This. recommendation does not duplicate the previous..request•from. the City to.the agencies on the vinyl chloride matter. Previous City .letters.related to adequacy of the Proposition 65 notice and r:elated,legal matters. The recommendation compliments the previous City actions in that. the City is requesting- a coordinated explanation,.of-the regulations applicable to the vinyl chloride emissions at the Landfill. Recommendation It is recommended by. the Waste management -and Environmental Quality Commission, -that the City Council'request.the.appropriate agencies to provide an.explanation.,of the different`concentration.levels of vinyl.. chloride for Proposition '65 purposes vs... enforcement and other purposes.. Michael L... Miller Environmental Services,Director.