Notice of Public Comment/Workshops for Draft Reference Exposure Levels for Carbonyl Sulfide

The Office of Environmental Health Hazard Assessment (OEHHA) is releasing for public review a draft document on the toxicity and derivation of Reference Exposure Levels (RELs) for Carbonyl Sulfide (COS).  RELs 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 implementing this requirement, OEHHA develops RELs for many air pollutants.  The COS RELs were developed using the most recent “Air Toxics Hot Spots Program Technical Support Document for the Derivation of Noncancer Reference Exposure Levels,” finalized by OEHHA in 2008.  

The COS REL document is being made available today. The posting of the document will commence a 60-day public review period that will end on December 16, 2014.  Public workshops will be held in Northern and Southern California at the following locations and times:

November 18, 2014
9:00 AM - 12:00 PM
Room CC-7
South Coast Air Quality Management District
21865 E. Copley Drive
Diamond Bar, CA 91765

November 21, 2014
1:00 PM - 4:00 PM
Cal/EPA Building, Sierra Hearing Room
1001 I Street,
Sacramento, CA 95812                                         

After the close of the public comment period, the documents will be revised as appropriate by OEHHA, and peer reviewed in 2015 by the State’s Scientific Review Panel on Toxic Air Contaminants. 

Please direct your comments on the documents, in writing or by e-mail, and 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
Telephone: (510) 622-3145

Information about dates and agenda for meetings of the Scientific Review Panel can be obtained from the California Air Resources Board website at