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Air Toxics

"Hot Spots" Information and Assessment Act (AB2588) 

The Air Toxics "Hot Spots" Information and Assessment Act (AB 2588, 1987, Connelly) was enacted in September 1987. Under this act, stationary sources are required to report the types and quantities of certain substances their facilities routinely release into the air. Emissions of interest are those that result from the routine operation of a facility or that are predictable, including but not limited to continuous and intermittent releases and process upsets or leaks.

The goals of the Air Toxics "Hot Spots" Act are to collect toxic emissions data, to identify facilities potentially having localized health risk impacts, to ascertain the extent of the health risks, and to notify nearby residents of significant risks. In September 1992, the "Hot Spots" Act was amended by Senate Bill (SB) 1731 (Calderon) to address the reduction of significant risks. The bill requires that owners of significant-risk facilities reduce their risks below the level of significance.

The Act requires that toxic air emissions from stationary sources (facilities) be quantified and compiled into an inventory according to criteria and guidelines developed by the ARB, that each facility be prioritized to determine whether a risk assessment must be conducted, that the risk assessments be conducted according to methods developed by the Office of Environmental Health Hazard Assessment (OEHHA), that the public be notified of significant risks posed by nearby facilities, and that emissions which result in a significant risk be reduced. Since the amendment of the statute in 1992 by enactment of SB 1731, facilities that pose a potentially significant health risks to the public are required to reduce their risks, thereby reducing the near-source exposure of Californians to toxic air pollutants. Owners of facilities found to pose significant risks by a district must prepare and implement risk reduction audit and plans within 6 months of the determination.

The benefits that come from this program are less risk to workers and to the public, reduced operation costs, demonstration of emission reduction options for other sources, and improved community relations.

The Act was further modified by AB 564, chaptered on September 19, 1997. The passage of AB 564 amended the Hot Spots statute in several ways, including adding provisions that: exempt specified low priority facilities from further compliance with the Hot Spots program; reinstate exempted facilities if specified criteria are met; specify an alternative evaluation process for facilities subject to district permit programs; and other changes to exempt specified facilities from further compliance with the Hot Spots Program.

In summary, the Air Toxics "Hot Spots" Act establishes a formal air toxics emission inventory risk quantification program for districts to manage. The goal of the Air Toxics "Hot Spots" Act is to collect emission data indicative of routine predictable releases of toxic substances to the air, to identify facilities having localized impacts, to evaluate health risks from exposure to the emissions, to notify nearby residents of significant risks, and, due to SB 1731, reduce risk below the determined level of significance. Information gathered from this program has complemented the ARB's existing toxic air contaminant program by locating sources of substances that were not under evaluation and by providing exposure data needed to develop regulations for control of toxic pollutants. Additionally, the program has been a motivating factor for facility owners to voluntarily reduce their facility's toxic emissions.

Continue with an Overview of the Air Toxics "Hot Spots" Information and Assessment Act at ARB's web site
Current Activity and resources at ARB's web site:]


Annual Reports on the AB 2588 Air Toxics "Hot Spots" Program

AB 2588 Air Toxics "Hot Spots" Annual Report - 2022 OperationsFacility Status 2022 Operations


AB 2588 Air Toxics "Hot Spots" Annual Report - 2021 OperationsFacility Status 2021 Operations


AB 2588 Air Toxics "Hot Spots" Annual Report - 2020 OperationsFacility Status 2020 Operations


AB2588 Air Toxics "Hot Spots" Annual Report - 2019 OperationaFacility Status 2019 Operations


AB 2588 Air Toxics "Hot Spots" Annual Report - 2018 OperationsFacility Status 2018 Operations


FRAQMD Program Guidelines

The FRAQMD implements the AB 2588  Air Toxics "Hot Spots" Information and Assessment Act Program for Yuba and Sutter counties, The Hot Spots Act requires facilities that are ranked as a high priority (see Prioritization) to submit a health risk assessment (HRA) to the air district.  A risk assessment, as defined under the Air Toxics "Hot Spots" Act, includes a comprehensive analysis of the dispersion of hazardous substances into the environment, the potential for human exposure, and a quantitative assessment of both individual and population-wide health risks associated with those levels of exposure. The risk assessments submitted by the facilities are reviewed by OEHHA and approved by the district. In addition, the district may require facilities in the intermediate and low priority categories to also submit a health risk assessment. OEHHA HRA Guidelines are available for download at ARB website. 

The District has adopted policy 2.12.1 and two manuals of procedures to implement the program.

2.12.1 Facility Prioritization and Risk Assessment Thresholds.pdfFacility Priorization GuidelinesToxic Risk Assessment Guidelines


For more information please contact the FRAQMD or visit