On January 24, 2018, the U.S. National Toxicology Program (NTP) held a meeting devoted to peer-reviewing the draft Report on Carcinogens monograph on antimony trioxide (CAS 1309-64-4), along with public comments received after its notification to the U.S. Federal Register on November 9, 2017.

According to the actions document published after the NTP meeting, the review panel “concurred with the statement that a significant number of persons living in the United States are exposed to antimony trioxide.” Further, the panel voted unanimously to “accept NTP’s level of evidence conclusion[s]” stating that “the data available from studies in human are inadequate to evaluate the relationship between human cancer and exposure specifically to antimony trioxide or other antimony compounds” and that there is “sufficient evidence of carcinogenicity for antimony trioxide from studies in experimental animals.”

Based on these conclusions, the panel unanimously voted in favor of accepting “NTP’s preliminary policy decision that antimony trioxide should be listed in the Report on Carcinogens as reasonably anticipated to be a human carcinogen based on sufficient evidence from studies in experimental animals and supporting mechanistic data.”

The meeting summary and the final Report on Carcinogens monograph on antimony trioxide will be published within three months on the Report on Carcinogens Peer Review Panels website.

Antimony trioxide is frequently used as a catalyst in the production of polyethylene terephthalate (PET) (FPF reported). It is also used as a synergist in a mixture with halogenated flame retardants in plastics and rubber. Antimony has been detected in recycled FCMs, pointing to a likely contamination by antimony trioxide from flame retardant mixtures due to improper separation of recycling streams (FPF reported). In 2017, the U.S. Agency for Toxic Substances and Diseases Registry published a draft toxicological profile for antimony, characterizing its toxicologic and adverse health effects.

Read more

NTP (November 29, 2017). “Draft Report on Carcinogens monograph on antimony trioxide.(pdf)

NTP (January 2018). “Actions from peer review of the draft Report on Carcinogens monograph on antimony trioxide.(pdf)

NTP (2018). “Past peer reviews of Report on Carcinogens monographs.

Chemical Watch (February 5, 2018). “Peer review panel agrees carcinogenicity of antimony trioxide.