The California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment (OEHHA) intends to list antimony (trivalent compounds) as known to the state to cause cancer under the Safe Drinking Water and Toxic Enforcement Act of 1986 (Proposition 65).
This action is being proposed pursuant to the “Labor Code” listing mechanism. OEHHA has determined that this substance meets the criteria for listing by this mechanism.
Background on Listing by the Labor Code mechanism
Health and Safety Code section 25249.8(a) incorporates California Labor Code section 6382(b)(1) into Proposition 65. The law requires that certain substances identified by the International Agency for Research on Cancer (IARC) be listed as known to cause cancer under Proposition 65. Labor Code section 6382(b)(1) refers to substances identified as human or animal carcinogens by IARC. OEHHA has adopted regulations concerning these listings in Title 27, Cal. Code of Regs., section 25904. As the lead agency for the implementation of Proposition 65, OEHHA evaluates whether a chemical’s listing is required.
Antimony (trivalent compounds) meets the requirements for listing as known to the state to cause cancer for purposes of Proposition 65.
IARC has published on its website a list entitled “Agents Classified by the IARC Monographs, Volumes 1 – 132″ (IARC, 2022). IARC concludes that antimony (trivalent compounds) is “probably carcinogenic to humans” (Group 2A) based on limited evidence for cancer in humans, sufficient evidence of carcinogenicity in experimental animals, and strong mechanistic evidence in human primary cells and in experimental systems (Karagas et al., 2022).