California updates list of chemicals known to cause cancer

Effective October 27, 2017, the Office of Environmental Health Hazard Assessment (OEHHA) is adding N,N‑dimethylformamide, 2‑mercaptobenzothiazole, and tetrabromobisphenol A to the list of chemicals known to the State of California to cause cancer for purposes of the Safe Drinking Water and Toxic Enforcement Act of 1986 (Proposition 65[1]).  

Health and Safety Code section 25249.8(a) incorporates California Labor Code section 6382(b)(1) into Proposition 65.  Regulations describing the process for listing chemicals via the Labor Code are set out in Title 27, Cal. Code of Regs., section 25904.  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.  An explanation of the carcinogenicity classifications used by IARC, and the Monographs development and peer review by the international working groups of scientific experts convened by IARC, may be found at the following URL: is external) (IARC Preamble).

The basis for the listing of N,N-dimethylformamide, 2-MErcaptobenzothiazole, and Tetrabromobisphenol A was described in a public notice published in the June 30, 2017, issue of the California Regulatory Notice Register (Register 2017, No. 26-Z).  The title of the notice was “Notice of Intent to List Chemicals by the Labor Code Mechanism: N,N‑dimethylformamide, 2‑mercaptobenzothiazole, and tetrabromobisphenol A.”  The publication of the notice initiated a 30-day public comment period.  We received three sets of comments on N,N‑dimethylformamide, 2‑mercaptobenzothiazole, and tetrabromobisphenol A.  The comments relevant to these three chemicals and OEHHA’s responses are posted with the Notice of Intent to List.

A complete, updated Proposition 65 list is published elsewhere in this issue of the California Regulatory Notice Register and is available on the OEHHA website at



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