Comment Period - Notice of Intent to List Styrene by the Labor Code Mechanism

The California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment (OEHHA) intends to list the chemical identified in the table below as known to the State to cause cancer under the Safe Drinking Water and Toxic Enforcement Act of 1986. The Act, commonly known as Proposition 65, is codified in Health and Safety Code section 25249.5 et seq. This action is being taken pursuant to the Labor Code mechanism contained in Health and Safety Code section 25249.8(a).

Chemical	CAS No.	Endpoint	Reference
Styrene	100-42-5	Cancer	NTP (2011)

Background on listing by the Labor Code mechanism: Health and Safety Code section 25249.8(a) incorporates California Labor Code sections 6382(b)(1) and 6382(d) into Proposition 65. Labor Code section 6382(d) incorporates chemicals or substances within the scope of the federal Hazard Communication Standards¹. The federal regulations, in turn, identify the National Toxicology Program (NTP) as a source for identifying chemicals that cause cancer². The NTP listing criteria and the process for report preparation and scientific peer review are described in the Report on Carcinogens³.

As the lead agency for the implementation of Proposition 65, OEHHA evaluates whether this chemical listing is required by Proposition 65.

OEHHA’s determination: Styrene meets the requirements for listing as known to the state to cause cancer for the purposes of Proposition 65.

In 2011, NTP published the Twelfth Edition of its Report on Carcinogens (NTP, 2011). In that report, NTP concluded that styrene is “‘reasonably anticipated to be a human carcinogen’ based on limited evidence of carcinogenicity from studies in humans, sufficient evidence of carcinogenicity from studies in experimental animals, and supporting data on mechanisms of carcinogenesis.” Therefore, this substance meets the requirements of Labor Code section 6382(d). The proposed listing also meets the standard set out in the recent Court of Appeal decision in the Styrene Information and Research Council v Office of Environmental Health Hazard Assessment (3rd District, Nov. 15, 2012) case because the NTP conclusion is based on sufficient evidence of carcinogenicity in experimental animals.

Opportunity for comment: OEHHA is providing this opportunity to comment as to whether the chemical identified above meets the requirements for listing as causing cancer specified in Health and Safety Code section 25249.8(a). Because this is a ministerial listing⁴, comments should be limited to whether the NTP Report on Carcinogens has identified the specific chemical or substance as a human carcinogen or potential human carcinogen. Under this listing mechanism, OEHHA cannot consider scientific arguments concerning the weight or quality of the evidence considered by NTP when it identified this chemical and will not respond to such comments if they are submitted.

OEHHA must receive comments by 5:00 p.m. on MONDAY, FEBRUARY 4, 2013. We encourage you to submit comments in electronic form, rather than in paper form. Comments transmitted by e-mail should be addressed to P65Public.Comments@oehha.ca.gov, and should include “NOIL for styrene” in the subject line. Comments submitted in paper form may be mailed, faxed, or delivered in person to the address below. A public workshop will be held only upon request. Such request must be made in writing within 10 days from the publication of this notice to the Proposition 65 Office of OEHHA via email at sam.delson@oehha.ca.gov or to the attention of the Proposition 65 Office at the address listed below:

Mailing Address:
Office of Environmental Health Hazard Assessment
P.O. Box 4010, MS-19B
Sacramento, California 95812-4010
Fax: (916) 323-8803
Street Address: 1001 I Street
Sacramento, California 95814

Any public comments received will be posted after the close of the comment period. If you have any questions, please contact Sam Delson at sam.delson@oehha.ca.gov or at (916) 445-6900.