Notice of Adoption of Reference Exposure Levels for Caprolactam
The Office of Environmental Health Hazard Assessment (OEHHA) is adopting Reference Exposure Levels (RELs) for caprolactam. Reference Exposure Levels are airborne concentrations of a chemical that are not anticipated to result in adverse non–cancer health effects for specified exposure durations in the general population, including sensitive subpopulations.
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 response to this statutory requirement, OEHHA has developed RELs for caprolactam. These were developed using the most recent “Air Toxics Hot Spots Program Technical Support Document for the Derivation of Noncancer Reference Exposure Levels,” released by OEHHA in 2008. This method allows for the estimation of acute, 8-hour and chronic RELs for use in Air Toxics Hot Spots program risk assessments.
A draft of the caprolactam RELs was released on May 21, 2010 to solicit public comment, and was discussed at public workshops in Oakland and Diamond Bar, CA during the subsequent 45-day public review period. The document was revised to reflect public comments, and peer reviewed by the State’s Scientific Review Panel on Toxic Air Contaminants (SRP). The document was reviewed and approved by the SRP in 2011.
The REL values are as follows:
Acute REL (for a 1–hour exposure): 50 µg/m3 (11 ppb)
8–Hour REL (for repeated 8–hour exposures): 7 µg/m3 (1.4 ppb)
Chronic REL (for long–term exposures): 2.2 µg/m3 (0.5 ppb)
Please direct any inquiries concerning technical matters or availability of the documents to:
Dr. John Budroe
Chief, Air Toxicology and Risk Assessment Section
Air, Community, and Environmental Research Branch
Office of Environmental Health Hazard Assessment
1515 Clay Street, 16th Floor
Oakland, CA, 94612
E–mail: John.Budroe@oehha.ca.gov
- Caprolactam