California adds three substances to Proposition 65 list

Regulatory background

• Proposition 65, formally known as the Safe Drinking Water and Toxic Enforcement Act of 1986, is a regulation that requires businesses to provide warnings to California consumers about significant exposures to chemicals that cause cancer, birth defects, or reproductive harm. Proposition 65 is administered by the Office of Environmental Health Hazard Assessment (OEHHA) and enforced by the California Attorney General (though that enforcement ability has been delegated to district attorneys and city attorneys in cities larger than 750,000 people).
• Chemicals may be added to the Proposition 65 list through several methods. The most common way that chemicals are added into Proposition 65 is through the Labor Code mechanism, which requires the addition of chemicals identified as causing cancer in human or laboratory animals by the World Health Organization’s International Agency for Research on Cancer (IARC). The office also will include chemicals identified by two state committees, the Carcinogen Identification Committee (CIC) and the Developmental and Reproductive Toxicant Identification Committee (DARTIC) via the State’s Qualified Experts mechanism. Along with CIC and DARTIC, the Proposition 65 statute also has designated several authoritative bodies, which automatically add a chemical to the list if one of the authoritative bodies determines that it causes cancer, birth defects, or reproductive harm. The current list of authoritative bodies includes the Environmental Protection Agency (EPA),the Food and Drug Administration (FDA), the National Institute for Occupational Safety and Health (NIOSH), the National Toxicology Program (NTP) of the US Department of Health and Human Services, and IARC. The final listing method required is the “Formally required to be labeled” mechanism, which requires that if a state or federal government requires that a chemical labeled or identified as causing cancer or birth defects or other reproductive harm, it must be added to the list.
• On September 22, 2023, the OEHHA announced its intent to list coal-tar pitch, fluoro-edenite fibrous amphiboles, and silicon carbide whiskers as chemicals known to California to cause cancer for the purposes of Proposition 65. These chemicals would be listed via the Labor Code Mechanism. The agency received no comments on the proposal during the comment period.

Finalized listing

• On November 17, 2023, the OEHHA announced that it was officially adding the three substances to the Proposition 65 list. The office officially determined that the substances had met the requirements for listing as known to the state to cause cancer for the purposes of Proposition 65.
• The decision stems back to several monographs that IARC released in 2012 and 2017. In Monograph 100F, IARC determined that coal-tar pitch is a Group 1 carcinogen, and in Monograph 111, determined that fluoro-edenite fibrous amphiboles are Group 1 carcinogens and silicon carbide whiskers are Group 2A carcinogens. Group 1 carcinogens are considered “carcinogenic to humans” under IARC classifications, whereas Group 2A carcinogens are considered “probably carcinogenic to humans” under the same classification structure. The OEHHA determined that based on the IARC classification, there was sufficient evidence of cancer in humans and animals to list coal-tar pitch and fluoro-edenite fibrous amphiboles, and sufficient evidence of cancer in animals to list silicon carbide whiskers.

Next steps

• The OEHHA will require warning labels on the substances (or products that contain them that provide enough exposure to the substances) within a year of the listing officially becoming active. In addition, the OEHHA will likely release safe harbor warning language which will help provide businesses with the specific warnings that will meet California regulations.

Featuring previous research by Walker Livingston.

To contact the author of this analysis, please email Walker Livingston.
To contact the editor of this analysis, please email Scott Stephens.

Key Documents and Dates

• OEHHA listing page (November 17, 2023)
• Notice of Intent (September 22, 2023)
• Coal-Tar Pitch (OEHHA)
• Fluoro-Edenite Fibrous Amphibole (OEHHA)
• Silicon Carbide Whiskers (OEHHA)