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NTP to Review Cobalt as a Candidate for the 14th Report on Carcinogens

June 2, 2015

The U.S. Department of Health and Human Services, National Toxicology Program (NTP) issued notice of a public meeting being held on July 22, 2015 on the peer review of a Draft Report on Carcinogens (RoC) Monograph on Cobalt and Certain Cobalt Compounds. Cobalt was selected as a candidate substance for listing in the RoC following solicitation of public comment, and NTP approved the selection in 2014.

Cobalt is a naturally occurring metallic element that exists in different forms, but is also present in a variety of compounds, all of which have varying valence states and water solubility. The RoC draft monograph includes cobalt metal and cobalt compounds that can release cobalt ions in biological fluids. Cobalt sulfate, which releases cobalt ions, was previously listed in the 13th RoC as reasonably anticipated to be a human carcinogen. Cobalt tungsten carbide: powders and hard metals, also is listed in the 13th RoC as reasonably anticipated to be a human carcinogen, but will not be included in NTP's current evaluation. The RoC draft monograph also does not include cobalt forms that have confounding exposures, such as cobalt carbides, alloys, radioactive forms of cobalt or cobalt compounds, and Vitamin B12, the latter of which does not release cobalt ions in vivo.

Cobalt and cobalt compounds are used in a variety of commercial, industrial, medical, and military applications, including: batteries, pigments, medical devices, and food packaging. Additionally, cobalt exposure can occur through the everyday consumption of food and drinking water.

NTP is expected to publish a preliminary agenda and the draft monograph by June 5, 2015. Written comments on the draft are due by July 8, 2015, and the deadline to register for oral comments is July 15, 2015.