Notice of Adoption of Cancer Inhalation Unit Risk Factor for p-Chloro-α,α,α-Trifluorotoluene
The Office of Environmental Health Hazard Assessment (OEHHA) is adopting a new cancer inhalation unit risk (IUR) and slope factor for p-Chloro-α,α,α-Trifluorotoluene (p-Chlorobenzotrifluoride, PCBTF, CAS No. 98-56-6) 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 PCBTF was developed using the most recent “Air Toxics Hot Spots Program Technical Support Document for Cancer Potency Factors,” finalized by OEHHA in 2009.
The values for PCBTF are as follows:
Inhalation Unit Risk Factor 8.6 x 10-6 (µg/m3)-1
Inhalation Slope Factor 3.0 x 10-2 (mg/kg-day)-1
A draft document for the PCBTF IUR was released on October 18, 2019, to solicit public comment and was discussed at public workshops in Oakland and Diamond Bar, CA during the subsequent 60-day public review period. The document was revised to reflect public comments, and peer reviewed by the State’s Scientific Review Panel (SRP) on Toxic Air Contaminants in February 2020 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, 16th Floor
Oakland, CA 94612
E–mail: john.budroe@oehha.ca.gov