The U.S. National Toxicology Program (NTP) recently completed its draft evaluation of antimony trioxide as a human carcinogen. While the draft is still open for peer review and comment, the current recommendation is to list this chemical as “reasonably anticipated to be a human carcinogen.”
In the parlance of the NTP Report on Carcinogens, this classification generally means that evidence overall is suggestive but not conclusive that the chemical can cause cancer in humans. Similar to the World Health Organisation’s carcinogenicity classifications, this evaluation only discusses plausibility/hazard, and does not evaluate risk.
Antimony trioxide has several uses, but one of them is as a flame retardant. Flame retardants have a long history of health, regulatory, and litigation issues. Starting with asbestos, moving to PCBs, polybrominated diphenyl ethers, and tris-halogenated compounds, these flame retardants have all been found to harm human health. Antimony trioxide is a bit different in that it is used in a much wider variety of industrial processes than other flame retardants. Because of the active toxicological literature and wide commercial footprint, Praedicat clients have been able to monitor antimony using its emerging risk profile.
A federal science panel soon will decide whether a chemical made or imported by BASF, DuPont, Campine NV, and Lanxess Corp. to make flame retardants, batteries, and plastics should be classified as a potential human carcinogen.