Request for Comments on Proposed Listing of Gallium Arsenide as Known to Cause Cancer and Hexafluoroacetone, Nitrous Oxide and Vinyl Cyclohexene Dioxide as Known to Cause Reproductive Toxicity

Jun 15, 2007

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 (Health and Safety Code section 25249.5 et seq., commonly known as Proposition 65). OEHHA is proposing to add gallium arsenide [CAS No. 1303-00-0] to the list of chemicals known to the state to cause cancer, for the purposes of Proposition 65, and hexafluoroacetone [CAS No. 684-16-2], nitrous oxide [CAS No. 10024-97-2] and vinyl cyclohexene dioxide [CAS No. 106-87-6] to the list of chemicals known to the state to cause reproductive toxicity, for the purposes of Proposition 65.

Health and Safety Code section 25249.8(a) requires that certain substances identified by the International Agency for Research on Cancer (IARC) or the National Toxicology Program (NTP), as described in Labor Code section 6382(b)(1) and (d), be included on the Proposition 65 list as causing cancer. Labor Code section 6382(b)(1) references substances identified as human or animal carcinogens by IARC, and Labor Code section 6382(d) references substances identified as carcinogens or potential carcinogens by IARC or NTP. In 2006, IARC issued the Volume 86 in its series IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. In this monograph, IARC concluded that gallium arsenide is carcinogenic to humans (Group 1).

Health and Safety Code section 25249.8(a) further requires that substances identified in Labor Code section 6382(d) as causing reproductive toxicity be included on the Proposition 65 list. Labor Code section 6382(d) captures any chemicals within the scope of the federal Hazard Communication Standard that are identified as reproductive toxicants. Chemicals fall within the scope of the Hazard Communication Standard if they are listed as hazardous in the latest edition of the American College of Governmental Industrial Hygienists (ACGIH) “Threshold Limit Values (TLVs).” The TLVs for hexafluoroacetone (male endpoint), nitrous oxide (developmental endpoint) and vinyl cyclohexene dioxide (male and female endpoints) were assigned on the basis of ACGIH’s findings of reproductive effects.

Pursuant to state law, IARC’s identification of gallium arsenide as carcinogenic to humans means that gallium arsenide must be included on the Proposition 65 list (Labor Code sections 6382(b)(1) and (d)). Also, ACGIH’s basing of the TLV’s for hexafluoroacetone, nitrous oxide and vinyl cyclohexene dioxide on reproductive toxicity means that hexafluoroacetone, nitrous oxide and vinyl cyclohexene dioxide must be included on the Proposition 65 list (Labor Code section 6382(d)). Therefore, OEHHA proposes to add gallium arsenide to the Proposition 65 list of chemicals known to cause cancer and hexafluoroacetone, nitrous oxide and vinyl cyclohexene dioxide to the Proposition 65 list of chemicals known to cause reproductive toxicity. Anyone wishing to provide comments as to whether gallium arsenide meets the requirements for listing as causing cancer specified in Health and Safety Code section 25249.8(a), by reference to Labor Code sections 6382(b)(1) and (d), or whether hexafluoroacetone, nitrous oxide and vinyl cyclohexene dioxide meet the requirements for listing as causing reproductive toxicity specified in Health and Safety Code section 25249.8(a), by reference to Labor Code section 6382(d), should send written comments in triplicate, along with any supporting documentations, by mail, email or by fax to:

Sam Delson
Office of Environmental Health Hazard Assessment
Street Address: 1001 I Street
Sacramento, California 95814
Mailing Address: P.O. Box 4010
Sacramento, California 95812-4010
Fax No.: (916) 323-8803
Telephone: (916) 445-6900
P65.Questions@oehha.ca.gov

Comments may also be delivered in person or by courier to the above address. It is requested, but not required, that written comments and supporting documentation by transmitted via email addressed to: P65.Questions@oehha.ca.gov. In order to be considered, comments must be postmarked (if sent by mail) or received at OEHHA (if hand-delivered, sent by FAX, or transmitted electronically) by 5:00 p.m. on July 16, 2007.

An informal workshop to discuss this proposed action has been scheduled for Monday, July 16, 2007, in the Coastal Hearing Room, California Environmental Protection Agency Building, 1001 I Street, 2nd Floor, Sacramento, California, as an opportunity for providing oral comments on this proposed action. The workshop will begin at 10:00 a.m. and will end when all business is conducted or 5:00 p.m. Those interested parties who wish to discuss or comment on this proposed action are encouraged to attend the workshop. Interested parties may also submit comments to OEHHA. All comments must be received at or prior to the workshop in order to be considered prior to a final action by OEHHA.