California Adds Coal-Tar Pitch Fluoro-Edenite Fibrous Amphibole and Silicon Carbide Whiskers to Cancer-Causing Chemicals List

Effective November 17, 2023, the California Office of Environmental Health Hazard Assessment (OEHHA) has included coal-tar pitch, fluoro-edenite fibrous amphibole, and silicon carbide whiskers in the list of chemicals known to cause cancer in California. This addition is made under the Safe Drinking Water and Toxic Enforcement Act of 1986, commonly known as Proposition 65, as outlined in the Health and Safety Code.

The decision to list these chemicals was based on information provided in a public notice published in the California Regulatory Notice Register on September 22, 2023.

Understanding Proposition 65

Proposition 65, established in November 1986 as a ballot initiative, protects California’s drinking water sources from contamination by chemicals known to cause cancer, birth defects, or other reproductive harm. It mandates businesses to inform Californians of potential exposure to such chemicals and to provide warnings.

These chemicals may be present in products, homes, workplaces, or released into the environment. Proposition 65 empowers Californians to make informed decisions about their chemical exposures and prohibits businesses from knowingly discharging significant amounts of listed chemicals into drinking water sources.

OEHHA’s Determination

Coal-tar pitch, fluoro-edenite fibrous amphibole, and silicon carbide whiskers meet the criteria to be listed as known to cause cancer under Proposition 65.

The International Agency for Research on Cancer (IARC) categorizes coal-tar pitch and fluoro-edenite fibrous amphibole as Group 1 ("carcinogenic to humans") and silicon carbide whiskers as Group 2A ("probably carcinogenic to humans"). IARC found sufficient evidence of carcinogenicity in humans and animals for coal-tar pitch and fluoro-edenite fibrous amphibole, and in animals for silicon carbide whiskers.

For an updated Proposition 65 chemical list, refer to the OEHHA website.