"Hot Spots" Risk Assessment

This page last reviewed November 27, 2013

Assembly Bill (AB) 2588 (Connelly), the Air Toxics "Hot Spots" Information and Assessment Act, requires facilities that are ranked as a high priority (see Prioritization) to submit a health risk assessment (HRA) to the air pollution control and air quality management districts (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 the Office of Environmental Health Hazard Assessment (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

Senate Bill 1731, which amends the "Hot Spots" Program, requires OEHHA to adopt risk assessment guidelines for the program using a full public review process. You can obtain a copy from the OEHHA website, or contact, either by email or by phone, Melanie Marty, Chief, Air Risk Assessment Unit, Office of Environmental Health Hazard Assessment, at (510) 622-3154.

Hotspots Analysis and Reporting Program

The Hotspots Analysis and Reporting Program (HARP) is a tool that assists with the programmatic requirements of the Air Toxics "Hot Spots" Program.

HARP is a single integrated software package that can be used by the air pollution control and air quality management districts (districts), facility operators, and other parties to promote statewide consistency, efficiency, and cost-effective development of facility and emission inventories and health risk assessments. HARP can also be used for other types of health risk assessments used in other programs (e.g., facility permitting).  To download a copy of the HARP software, please go to the HARP download page.

ARB Recommended Interim Risk Management Policy for Inhalation-Based Residential Cancer Risk

The ARB recommends that the Interim Policy for Inhalation-Based Residential Cancer Risk be used to augment the OEHHA Air Toxic Hot Spots Program Guidance Manual for Preparation of Health Risk Assessment where a single cancer risk value (rather than a range of risk) is needed or prudent for characterizing risk or where a single risk value is used for risk management decision-making for residential receptors. To download the document, click here.

Frequently Asked Questions

Q1) Why are we recommending this approach?
Q2) When are we recommending this policy be used?
Q3) Why are we recommending the 80th percentile as a minimum exposure value for risk management purposes?
Q4) To which type of risk assessment analysis and receptor does this interim policy apply?
Q5) What breathing rate should be used when calculating residential cancer risk for the 80th percentile?
Q6) What breathing rates are used for children and workers?
Q7) Is the 80th percentile the only breathing rate that should be included in a risk assessment?
Q8) Where can I learn more about the Tiered-approach to risk assessment (Tier 1 to Tier 4) that is referred to in the interim policy?
Q9) What is the definition of a dominant exposure pathway in a multipathway cancer risk assessment?
Q10) How does the Derived (OEHHA) Cancer Risk method work?
Q11) How does the Derived (Adjusted) Cancer Risk method work?
Q12) When do the Derived (OEHHA) and the Derived (Adjusted) methods yield the same result?

Consolidated Table of OEHHA / ARB Approved Risk Assessment Health Values
The Consolidated Table of OEHHA / ARB Approved Risk Assessment Health Values is a quick look-up table of all cancer potency values and noncancer acute and chronic Reference Exposure Levels (RELs) that are available for use in the AB 2588 Air Toxics "Hot Spots" Program. This table includes cancer potency values and noncancer reference exposure levels (RELs) that have been approved by the Office of Environmental Health Hazard Assessment (OEHHA) and the Air Resources Board (ARB) or are listed in the California Air Pollution Control Officers Association's (CAPCOA) Risk Assessment Guidelines (1993).  The OEHHA is currently in the process of developing new risk assessment guidelines that will update and replace the CAPCOA guidelines. If you have any questions, please call the Air Resources Board at (916) 323-4327.

Review of Updated and Screening HRAs
In 1997, the staff of the ARB, the OEHHA, and the districts collaborated to develop a streamlined process for the submittal and review of updated, and screening, health risk assessments (HRAs). That joint effort resulted in the development of a set of forms (see HRA forms MSWord - PDF) intended to accompany the submittal of updated, or screening, HRAs to the appropriate district and to OEHHA. There is also a list of the minimum data fields required when submitting an updated, or screening, HRA for those individuals that chose to not use the forms developed.

Industrywide Risk Assessments

Currently, CAPCOA, in cooperation with OEHHA and the ARB, is developing three industrywide risk assessment procedures. The purpose of these industry specific assessments is to assist both the districts and facilities with the emission inventory and risk assessment requirements of the "Hot Spots" program (see Overview of "Hot Spots" Program).

The three industries covered by the industrywide assessments are: auto bodyshops, gasoline service stations, and dry cleaning facilities. Facilities which meet a specific set of requirements outlined in the law are candidates for an industrywide assessment. The requirements are focused on small businesses that are from the same industrial class, where individual compliance would impose severe economic hardships, and where emissions are easily and generically characterized.

Please refer to the Industrywide Risk Assessment List below to download a copy of a particular risk assessment or to get in contact with the ARB or district staff person responsible for that guideline. To obtain a hardcopy of any industrywide risk assessment guideline document, please contact ARB at (916) 323-4327.

Industrywide Risk Assessment Guidelines List

Industry Status File Format ARB / District
Auto Bodyshops Completed PDF (11.4MB) ARB
Narci Gonzalez
(916) 324-8175
Dry Cleaners In Progress - - ARB
Mei Fong
(916) 324-2570
Bay Area AQMD
(415) 771-6000
Gasoline Service Stations Completed PDF (761K) ARB
Kirk Rosenkranz
(916) 327-7843
David Craft
Monterey Bay Unified APCD
(408) 647-9411 x 218
Revised Appendix E
  PDF (196K)