Chemicals Listed Effective July 9, 2004 as Known to the State of California to Cause Cancer: “aristolochic acids” and “herbal remedies containing plant species of the genus Aristolochia”

The Office of Environmental Health Hazard Assessment (OEHHA) of the California Environmental Protection Agency is adding “aristolochic acids” and “herbal remedies containing plant species of the genus Aristolochia” 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, Proposition 65). The listing of "aristolochic acids” and “herbal remedies containing plant species of the genus Aristolochia” is effective July 9, 2004.

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 sections 6382(b)(1) and (d), be included on the Proposition 65 list. 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. Aristolochic acids were identified by IARC as animal carcinogens. Herbal remedies containing plant species of the genus Aristolochia, were identified by IARC as carcinogenic to humans.

The basis for the listing of “aristolochic acids” and “herbal remedies containing plant species of the genus Aristolochia” on the Proposition 65 list was described in OEHHA’s Request for Comment on Proposed Listing of Aristolochic Acids and Herbal Remedies Containing Plant Species of the Genus Aristolochia As Known to Cause Cancer published in the May 14, 2004, issue of the California Regulatory Notice Register (Register 2004, No. 20-Z). Specifically, IARC issued the monograph "Some Traditional Herbal Medicines, Some Mycotoxins, Naphthalene and Styrene,” (Volume 82) in 2002 in its series IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, and concluded “there is sufficient evidence in experimental animals for the carcinogenicity of aristolochic acids.” In addition, IARC classified “herbal remedies containing plant species of the genus Aristolochia as “carcinogenic to humans (Group 1).” OEHHA received four public comments supporting the listing of these chemicals.

OEHHA analyses of dose-response data to establish the no significant risk levels (NSRLs) for these chemicals under Proposition 65 have not been conducted. The priority status of the development of such analyses will be announced in a future OEHHA Proposition 65 Status Report for Safe Harbor Levels, available at /proposition-65.

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

Cancer

Chemical
CAS No.
Toxicological Endpoint
Listing Mechanism1
Aristolochic acids
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cancer
LC
Herbal remedies containing plant species of the genus Aristolochia
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cancer
LC

1Listing mechanism:
LC – “Labor Code” mechanism (Labor Code sections 6382(b)(1) and (d))