Air Toxics Hot Spots

The Air Toxics "Hot Spots" Information and Assessment Act (AB 2588, Connelly) was enacted in 1987, and requires stationary sources of pollutants to report the types and quantities of certain substances routinely released into the air. The goals of the Air Toxics "Hot Spots" Act are to collect emission data, to identify facilities having localized impacts, to ascertain health risks, to notify nearby residents of significant risks, and to reduce those significant risks to acceptable levels.

Guideline Values for Health Risk Assessment

Current Hot Spots Guidelines Technical Support Documents

Hot Spots Reports, Notices and Documents

Oct 18, 2019: Public Comment Period and Workshops on the Draft Hot Spots Cancer Inhalation Unit Risk Factors for p Chloro-α,α,α-trifluorotoluene (p-chlorobenzotrifluoride, PCBTF)
The Office of Environmental Health Hazard Assessment (OEHHA) is releasing a document for public review that summarizes the carcinogenicity and derivation of a cancer inhalation unit risk factor (IUR...
Sep 6, 2019: Notice of Adoption of Reference Exposure Levels for Hexamethylene Diisocyanate (Monomer and Polydiisocyanates)
RELs are airborne concentrations of a chemical that are not anticipated to result in adverse noncancer health effects for specified exposure durations in the general population, including sensitive...
Sep 4, 2019: Cobalt and Cobalt Compounds Cancer Inhalation Unit Risk Factor (IUR) Document - Scientific Review Panel on Toxic Air Contaminants (SRP) Review Draft
IURs are used to estimate lifetime cancer risks associated with inhalation exposure to a carcinogen.
May 31, 2019: Draft Document Summarizing the Toxicity and Derivation of Reference Exposure Levels (RELs) for Toluene
The Office of Environmental Health Hazard Assessment (OEHHA) is releasing a draft document summarizing the toxicity and derivation of Reference Exposure Levels (RELs) for Toluene.  This document will...
Apr 10, 2019: Extension of the Public Comment Period for the Proposed Cancer Inhalation Unit Risk Factors for Cobalt and Cobalt Compounds
The Office of Environmental Health Hazard Assessment (OEHHA) is releasing a document for public review that summarizes the carcinogenicity and derivation of cancer inhalation unit risk factors (IURs...
Mar 8, 2019: Public Comment Period and Workshops on the Draft Hot Spots Cancer Inhalation Unit Risk Factors for Cobalt and Cobalt Compounds
The Office of Environmental Health Hazard Assessment (OEHHA) is releasing a document for public review that summarizes the carcinogenicity and derivation of cancer inhalation unit risk factors (IURs...
Feb 4, 2019: Proposed Reference Exposure Levels for Hexamethylene Diisocyanate (Monomer and Polyisocyanates) - Scientific Review Panel Draft
A draft of the HDI REL document was released for a 75-day public review and comment period on December 1, 2017.  One set of comments was received.  Those comments and the OEHHA responses to those...
Aug 16, 2018: Notice of Adoption of Cancer Inhalation Unit Risk and Slope Factors and Cancer Oral Slope Factor for Tert-Butyl Acetate
The Office of Environmental Health Hazard Assessment (OEHHA) is adopting a new cancer inhalation unit risk factor (IUR) for tert-butyl acetate (TBAc).  IURs are used to estimate lifetime cancer risks...
May 4, 2018: Notice of Adoption of Reference Exposure Levels for Ethylene Glycol Mono-N-Butyl Ether
The adopted RELs cover different types of exposure to EGBE in air: infrequent 1-hour exposures, repeated 8-hour exposures, and continuous long-term exposure.
Jan 26, 2018: Extension of Public Comment Period for the Proposed Reference Exposure Levels for Toluene
OEHHA received a request from the to extend the public comment period. This notice extends the comment period to February 14, 2018.

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