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City of Pleasanton—Hidden Canyon Residences and Preserve Air Quality Draft EIR 3.2-20 FirstCarbon Solutions https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480016/EIR/3 - Draft EIR/21480016 Sec03-02 Air Quality.docx assumed to have no safe threshold below which health impacts will not occur. Noncarcinogenic TACs differ in that there is a safe level in which it is generally assumed that no negative health impacts would occur. These levels are determined on a pollutant-by-pollutant basis. It is important to understand that TACs are not considered criteria air pollutants and thus are not specifically addressed through the setting of ambient air quality standards. Instead, the EPA and ARB regulate TACs (known by the EPA as HAPs) through statutes and regulations that generally require the use of Maximum Available Control Technology (MACT) or Best Available Control Technology (BACT) to limit emissions. Those, in conjunction with additional rules set forth by the BAAQMD, establish the regulatory framework for TACs. Federal Regulations The CAA requires the EPA to regulate toxic air pollutants, also known as air toxics, from large industrial facilities in two phases. The first phase is “technology-based,” where EPA develops standards for controlling the emissions of TACs from sources in an industry group (or “source category.”) These MACT standards are based on emissions levels that are already being achieved by the controlled and low-emitting sources in an industry. The second phase is a “risk-based” approach called residual risk. Here, EPA must determine whether more health-protective standards are necessary. Within 8 years of setting the MACT standards, the CAA requires EPA to assess the remaining health risks from each source category to determine whether the MACT standards protect public health with an ample margin of safety and protect against adverse environmental effects. Every 8 years after setting the MACT standards, the CAA also requires EPA to review and revise the standards, if necessary, to account for improvements in air pollution controls and/or prevention. The first 8-year review, when combined with the residual risk review, is called the risk and technology review. State Regulations California has a comprehensive and effective air toxics program. Several pieces of legislation form the basis for ARB to identify and control air toxics from a multitude of sources, inform the public of significant toxic exposures, and provide ways to reduce risks from these exposures. The key programs outlined by legislative mandates include the Toxic Air Contaminant Identification and Control Program (Assembly Bill [AB] 1807), the Air Toxics Hot Spots Information and Assessment Act (AB 2588), the Children’s Environmental Health Protection Act, and the Community Air Protection Program. The ARB has identified more than 200 toxic air pollutants and has adopted and implemented 25 ATCMs. Some of the air toxics that have been identified and controlled include: benzene in gasoline, hexavalent chromium from chrome platers, perchloroethylene from dry cleaners, and diesel exhaust from cars and trucks. The Community Air Protection Program (AB 617) was signed into law to reduce exposure in communities experiencing high cumulative exposure to air pollution including air toxic chemicals, many of which occur in disadvantaged communities.24 24 California Air Resources Board (ARB). 2024. Website: https://ww2.arb.ca.gov/our-work/programs/air-toxics-program. Accessed February 25, 2025.