Proposed Reference Exposure Levels for Toluene Diisocyanate and Methylene Diphenyl Diisocyanate – SRP Drafts 2015

The Office of Environmental Health Hazard Assessment (OEHHA) is releasing two updated draft documents for review by the State's Science Review Panel on Toxic Air Contaminants (SRP), one summarizing the toxicity and derivation of Reference Exposure Levels (RELs) for Toluene Diisocyanate (TDI) and the other summarizing the toxicity and derivation of RELs for Methylene Diphenyl Diisocyanate (MDI). These documents have already been reviewed once by the SRP on February 6, 2015. Members of the Panel ask staff to provide more information on several issues. The updated SRP review draft documents will again be reviewed by the SRP at their meeting on June 19, 2015. 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 response to this statutory requirement, OEHHA develops RELs for many air pollutants. The MDI and TDI 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.

These two updated draft documents are being release to the public, but we are not seeking further comments from the public on the draft documents at this time.

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
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 web page at: http://www.arb.ca.gov/srp/srpmeetings.htm.

Chemical Reference

• Methylene Diphenyl Diisocyanate (MDI)
• Toluene Diisocyanates (2,4 and 2, 6)

Related Notices

• Proposed Reference Exposure Levels for Toluene Diisocyanate and Methylene Diphenyl Diisocyanate – SRP Drafts

  Nov 14, 2014
  Extension of Public Comment Period for Proposed Revised Reference Exposure Levels For Toluene Diisocyanate And Methylene Diphenyl Diisocyanate 2014

  Aug 22, 2014
  Notice of Public Comment/Workshops for Proposed Revised Reference Exposure Levels for Toluene Diisocyanate and Methylene Diphenyl Diisocyanate

  Jul 4, 2014
  Extension of Public Comment Period for Proposed Revised Reference Exposure Levels For Toluene Diisocyanate And Methylene Diphenyl Diisocyanate

  Jun 17, 2010
  Notice of Public Workshops on Proposed Reference Exposure Levels for Methylene Diphenyl Diisocyanate, Toluene Diisocyanate, and Caprolactam

  Jun 2, 2010
  Notice of Public Comment for Proposed Revised Reference Exposure Levels for Toluene Diisocyanate and Methylene Diphenyl Diisocyanate

  Apr 23, 2010