California Air Toxics Program - Background

This page last reviewed December 13, 2017


The California Air Resources Board's (CARB / Board) established in the early 1980's the statewide comprehensive air toxics program. Please view our brochure: "Reducing Toxic Air Pollutants in California's Communities." The Toxic Air Contaminant Identification and Control Act (AB 1807, Tanner 1983) created California's program to reduce exposure to air toxics. The Air Toxics "Hot Spots" Information and Assessment Act (AB 2588, Connelly 1987) supplements the AB 1807 program, by requiring a statewide air toxics inventory, notification of people exposed to a significant health risk, and facility plans to reduce these risks.

Under AB 1807, the ARB is required to use certain criteria in the prioritization for the identification and control of air toxics. In selecting substances for review, the CARB must consider criteria relating to "the risk of harm to public health, amount or potential amount of emissions, manner of, and exposure to, usage of the substance in California, persistence in the atmosphere, and ambient concentrations in the community" [Health and Safety Code section 39666(f)]. AB 1807 also requires the CARB to use available information gathered from the AB 2588 program to include in the prioritization of compounds. This report includes available information on each of the above factors required under the mandates of the AB 1807 program. More details about the AB 1807 and AB 2588 are below.

AB 1807 Program

In 1983, the California Legislature established a two-step process of risk identification and risk management to address the potential health effects from air toxic substances and protect the public health of Californians. During the first step (identification), the CARB and the Office of Environmental Health Hazard Assessment (OEHHA) determined if a substance should be formally identified as a toxic air contaminant (TAC) in California. During this process, the CARB and the OEHHA staff draft a report that served as the basis for this determination. The CARB staff assessed the potential for human exposure to a substance and the OEHHA staff evaluated the health effects. A thorough public process assured accountability and public input. Staff conducted public workshops to allow for direct exchanges of information with interested constituencies, published the draft risk assessments, and widely distributed with a public notice requesting comments. The final risk assessment (identification) report includes a record of the public comments and how they were addressed. After the CARB and the OEHHA staff hold several comment periods and workshops, the report was then submitted to an independent, nine member, Scientific Review Panel (SRP), who reviewed the report for its scientific accuracy. After the SRP's approval CARB staff prepared a hearing notice and draft regulation to formally identify the substance as a TAC. Based on the input from the public and the information gathered from the report, the Board decided whether to identify a substance as a TAC.

In the second step (risk management), the CARB reviewed the emission sources of an identified TAC to determine if any regulatory action is necessary to reduce the risk. The analysis included a review of controls already in place, the available technologies and associated costs for reducing emissions, and the associated risk. Public outreach was an essential element in the development of a control plan and any control measure to ensure that the CARB efforts were cost-effective and appropriately balanced public health protection and economic growth.

In 1993, the California Legislature amended the AB 1807 program for the identification and control of TACs (AB 2728). Specifically, AB 2728 required the CARB to identify the 189 federal hazardous air pollutants as TACs. For those substances that have not previously been identified under AB 1807 and identified under AB 2728, health effects values will need to be developed. This report served as a basis for that evaluation. For substances that were not identified as TACs and are on the TAC Identification List, this report provided information to evaluate which substances may be entered into the air toxics identification process.

AB 2588 "Hot Spots" Program

In September 1987, the California Legislature established the AB 2588 air toxics "Hot Spots" program. It requires facilities to report their air toxics emissions, ascertain health risks, and to notify nearby residents of significant risks. The emissions inventory and risk assessment information from this program has been incorporated into this report. In September 1992, the "Hot Spots" Act was amended by Senate Bill 1731 which required facilities that pose a significant health risk to the community to reduce their risk through a risk management plan.