Request for Information on Methyl Tertiary-Butyl Ether (MTBE)

The California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment (OEHHA) is the lead agency for the implementation of the Safe Drinking Water and Toxic Enforcement Act of 1986 (Proposition 65).

The Carcinogen Identification Committee and Developmental and Reproductive Toxicant (DART) Identification Committee of OEHHA’s Science Advisory Board advise and assist OEHHA in compiling the list of chemicals known to the State to cause cancer and/or reproductive toxicity which is mandated by Health and Safety Code Section 25249.8. The Committees serve as the State’s qualified experts for rendering an opinion as to whether a chemical has been clearly shown through scientifically valid testing according to generally accepted principles to cause cancer or reproductive toxicity.

The Local Drinking Water Protection Act of 1997 [Assembly Bill 592 (Kuehl) and Senate Bill 1189 (Hayden)] requires the State’s qualified experts for Proposition 65 (i.e., the Carcinogen Identification Committee and DART Identification Committee) to make a finding on or before January 1, 1999 as to whether methyl tertiary-butyl ether (MTBE) has been clearly shown through scientifically valid testing according to generally accepted principles to cause cancer or reproductive toxicity.

In accordance with the OEHHA’s process for preparing information on candidate chemicals for review by the State’s qualified experts, OEHHA will review the available carcinogenicity and reproductive toxicity literature and data on MTBE. The Carcinogen Identification Committee will consider the carcinogenicity information summarized by OEHHA before making a recommendation regarding the carcinogenicity of MTBE. The DART Identification Committee will similarly consider the OEHHA summary of reproductive toxicity information before making a recommendation regarding the reproductive and developmental toxicity of MTBE. Interested parties or members of the public wishing to provide information relevant to an assessment of the carcinogenicity or reproductive and developmental toxicity of MTBE should forward such information to the address given below. The publication of this notice marks the start of a 60-day data call-in period. This period ends on February 2, 1998. The information received during this data call-in period will be reviewed and considered by OEHHA as it develops the draft cancer and reproductive and developmental toxicity hazard identification documents on MTBE.

OEHHA welcomes public participation and public input as part of these scientific assessments. If there is sufficient public interest, a public workshop or other public forum will be held to encourage scientific dialogue prior to completion of the draft hazard identification documents.

Notification of the availability of the draft hazard identification documents and of the time, date, location, and agenda of any workshops and of the meetings of the Carcinogen Identification Committee and the DART Identification Committee where MTBE will be discussed will be provided in future notices published in the California Regulatory Notice Register and posted on OEHHA’s Home Page. It is anticipated that the draft hazard identification documents will be made available for a 60-day public comment period prior to the committee meeting at which MTBE will be considered.

Relevant information on MTBE should be sent in triplicate by mail or fax to:

the Proposition 65 Office
Office of Environmental Health Hazard Assessment
Post Office Box 4010
Sacramento, CA 95812-4010
Fax (916) 327-1097
Telephone: (916) 445-6900

Relevant information may also be delivered in person or by courier to the above address.

In order to be considered, the relevant information must be postmarked (if sent by mail) or received at OEHHA (if hand-delivered or sent by fax) by 5:00 PM on February 2, 1998.