Notice of Adoption of Cancer Inhalation Unit Risk and Slope Factors for 1-Bromopropane

Dec 9, 2022

Download cancer inhalation unit risk (IUR) for 1-Bromopropane

The Office of Environmental Health Hazard Assessment (OEHHA) is adopting new cancer inhalation unit risk (IUR) and slope factors for 1-Bromopropane (1-BP) for use in the Air Toxics Hot Spots Program. IURs are used to estimate lifetime cancer risks associated with inhalation exposure to a carcinogen.

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)). In implementing this requirement, OEHHA develops new IURs and revises existing IURs for many air pollutants. The IUR for 1-BP was developed using the most recent guidance, “Air Toxics Hot Spots Program Technical Support Document for Cancer Potency Factors,” finalized by OEHHA in 2009.

The values for 1-BP are as follows:

Inhalation Unit Risk Factor 3.7 × 10^-6 (µg/m³)^-1
Inhalation Slope Factor 1.3 × 10^-2 (mg/kg-day)^-1

A draft document for the 1-BP IUR was released on May 12, 2021, to solicit public comment and was discussed at a virtual public workshop during the subsequent 45-day public review period. No public comments were received on the document. The document was peer reviewed by the State’s Scientific Review Panel (SRP) on Toxic Air Contaminants in October 2021 before being finalized.

Please direct any inquiries concerning technical matters or availability of the documents to:

Dr. John Budroe, Chief
Air Toxicology and Risk Assessment Section
Office of Environmental Health Hazard Assessment
1515 Clay Street, 16^th Floor
Oakland, CA 94612

E–mail: john.budroe@oehha.ca.gov