California Air Resources Board

The Toxic Air Contaminant Identification and Control Act (AB 1807, Tanner 1983) created California's program to reduce exposure to air toxics.  The program involves a two-step process: 1) risk identification, and 2) risk management.

Risk Identification

In this step, and upon CARB's request, the Office of Environmental Health Hazard Assessment (OEHHA) evaluates the health effects of substances other than pesticides and their pesticidal uses.  Substances with the potential to be emitted or are currently being emitted into the ambient air may be identified as a toxic air contaminants (TAC).  

The following actions occur when identifying a substance as a TAC:

1. CARB and OEHHA draft a report that serves as the basis for the determination of a substance as a TAC. CARB assesses the potential for human exposure, and OEHHA evaluates its health effects.
2. CARB creates, publishes and distributes a draft risk assessment of the substance soliciting public comment.
3. The independent, nine member, Scientific Review Panel (SRP) on TACs, reviews the draft report for its scientific accuracy.
4. After SRP's review, CARB prepares a hearing notice on its proposed regulation to formally identify the substance as a TAC.
5. After conducting a public hearing and pursuant to legislation, CARB lists the substance(s) determined to be a TAC.

A critical element of the TAC identification process is engaging with the public.  Through public notices, CARB staff conducts public workshops to allow for direct exchange of information with interested groups and constituencies.  A thorough public process assures accountability and encourages public input.  To date, CARB has identified approximately 200 TACs. 

Risk Management

Once a substance is identified as a TAC, and with the participation of local air districts, industry, and interested public, CARB prepares a report that outlines the need and degree to regulate the TAC through a control measure. The report includes an evaluation of the following:

TAC emissions:

• Present and future sources
• Persistence and dispersion in ambient air
• Exposure and risk
  • Present and potential for adverse health, safety, or environmental impacts
• Availability and feasibility of control technology
• Costs of control measure

Additional steps in developing a control measure includes:

1.  Similar to the process of identifying a substance as a TAC, public outreach is an essential element.  CARB staff conducts public workshops, meets with industry and environmental groups, and stakeholders to be informed and address concerns. 

2. Based on public input and direction from the Board, CARB staff prepares a proposed regulation order prior formally adopting the airborne toxic control measure.

When developing an airborne toxic control measure, CARB staff examines the cost effectiveness and feasibility of achieving emission reductions compared to protecting public health and economic growth.

Currently, CARB has twenty-six mobile and stationary airborne toxic control measures.