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In accordance with Health and Safety Code, Section 44300 et seq. (The Air Toxics Hot Spots Information and Assessment Act, AB 2588, Connelly as amended by SB 1731, Calderon), the Director of the Office of Environmental Health Hazard Assessment (OEHHA) hereby adopts The Air Toxics Hot Spots Program Guidance Manual for Preparation of Health Risk Assessments.

OEHHA is releasing the final version of the document, Air Toxics Hot Spots Program Guidance Manual for the Preparation of Risk Assessments by posting on our Web site. This Guidance Manual has been developed by OEHHA, in conjunction with the Air Resources Board (ARB), for use in implementing the Air Toxics Hot Spots Program (Health and Safety Code Section 44360). OEHHA is required to develop guidelines for conducting health risk assessments under the Air Toxics Hot Spots Program (Health and Safety Code Section 44360 (b) (2)). OEHHA developed four Technical Support Documents (TSDs) in response to this statutory requirement, which provided the scientific basis for values used in assessing risk from exposure to facility emissions. The four TSDs describe acute reference exposure levels (RELs), chronic RELs, cancer potency factors, point estimates and distributions for exposure parameters, and the general exposure assessment methodology. These TSDs underwent public and peer review, were approved by the State's Scientific Review Panel on Toxic Air Contaminants, and adopted by OEHHA for use in the Air Toxics Hot Spots program. The Guidance Manual combines the critical information from the four TSDs into a manual for the preparation of health risk assessments. The guidance manual also includes the newly adopted Toxicity Equivalents Factors for dioxin-like compounds as well as the latest chronic RELs. A computer program, the Hot Spots Analysis and Reporting Program (HARP) has been developed by ARB as a tool to implement the risk assessments as outlined in this guidance manual. The HARP program will be available from ARB very shortly.

The document is available for download in one 4.4 Mb file (excluding appendices) or in several sections. Follow a link below to download.

Follow this link to download the entire document (including appendices) (4.4Mb)

Follow this link to download the entire document (excluding appendices) (2.6Mb)

Follow this link to download appendices A-L (1.76Mb)

Follow this link to download OEHHA's responses to major comments (352kb)

Follow this link to download OEHHA's responses to major comments submitted to ARB. (385kb)

Information about dates and agenda for meetings of the Scientific Review Panel can be obtained from the ARB web page at http://www.arb.ca.gov/srp/srp.htm.

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