Chemical Listed Effective March 4, 2005 as Known to the State of California to Cause Cancer: 2,4-Hexadienal (89% trans, trans isomer; 11% cis, trans isomer)

The Office of Environmental Health Hazard Assessment (OEHHA) of the California Environmental Protection Agency is adding 2,4-hexadienal (89% trans, trans isomer; 11% cis, trans isomer) to the list of chemicals known to the state to cause cancer for purposes of the Safe Drinking Water and Toxic Enforcement Act of 1986 (Health and Safety Code section 25249.5 et seq., Proposition 65). The listing of the chemical is effective March 4, 2005.

2,4-Hexadienal (89% trans, trans isomer; 11% cis, trans isomer) is listed as a chemical known to the State of California to cause cancer. The listing of this chemical is based on a formal identification by an authoritative body (i.e., the National Toxicology Program [“NTP”]) that the chemical causes cancer. Regulations governing the listing of chemicals under the “authoritative bodies” mechanism are published in Title 22, Cal. Code of Regs. Section 12306.

The reader is directed to the Notice of Intent to List 2,4-hexadienal published in the December 31, 2004, issue of the California Regulatory Notice Register (Register No. 2004, No. 53-Z) for the documentation supporting OEHHA’s determination that the criteria for administrative listing have been satisfied for this chemical. The documentation was developed to explain the basis for listing this chemical via the authoritative bodies provision of Proposition 65. OEHHA analyses of dose-response data to establish the no significant risk level (NSRL) for this chemical under Proposition 65 have not been conducted. The priority status of the development of an NSRL for 2,4-hexadienal (89% trans, trans isomer; 11% cis, trans isomer) will be announced in a future OEHHA Proposition 65 Status Report for Safe Harbor Levels.

A complete, updated Proposition 65 list is published elsewhere in this issue of the California Regulatory Notice Register.

The following table outlines the addition of 2,4-hexadienal (89% trans, trans isomer; 11% cis, trans isomer) to the Proposition 65 chemical list as known to the State to cause cancer:

Chemical CAS No. Toxicological Endpoint Listing Mechanism1
2,4-Hexadienal (89% trans, trans isomer; 11% cis, trans isomer)
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cancer AB

1Listing mechanism: AB – “authoritative bodies” mechanism (Title 22, Cal. Code of Regs. section 12306)