The Office of Environmental Health Hazard Assessment (OEHHA) has determined that glyphosate (CAS No. 1071-83-6) will be added to the list of chemicals known to the state to cause cancer for purposes of Proposition 65. The effective date of this listing will be determined following a decision from the Court of Appeal regarding a request for a stay in the pending case Monsanto v OEHHA. A separate Notice will be published, along with an updated Proposition 65 list, when the chemical is added to the list.
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 processes used by IARC to develop these classifications may be found in the IARC Preamble, which is also available at the following URL: http://monographs.iarc.fr/ENG/Preamble/CurrentPreamble.pdf(link is external).
The basis for the listing of glyphosate was described in a public notice published in the September 4, 2015, issue of the California Regulatory Notice Register (Register 2015, No. 36-Z). The title of the notice was “Notice of Intent to List Chemicals by the Labor Code Mechanism: Tetrachlorvinphos, Parathion, Malathion, and Glyphosate.” The publication of the notice initiated a public comment period. OEHHA previously reviewed and responded to comments on the listing of tetrachlorvinphos, parathion and malathion. A public notice of the listings of these compounds was published in the May 20, 2016 issue of the California Regulatory Notice Register (Register 2016, No. 21-Z); and responses to the comments received were posted on OEHHA’s website on May 20, 2016.
OEHHA received 9,183 comments relevant to glyphosate and OEHHA’s responses are posted with the Notice of Intent to List and are available on OEHHA’s website.
OEHHA is concurrently proposing a safe harbor level (No Significant Risk Level or NSRL) for glyphosate. The NSRL should be finalized prior to the effective date of the warning requirement for exposures to glyphosate.
In summary, glyphosate will be listed under Proposition 65 as known to the State to cause cancer, as follows:
*Listing mechanism: LC – “Labor Code” mechanism (Health and Safety Code section 25249.8(a) and Title 27 Cal. Code of Regs. section 25904)
** The International Agency for Research on Cancer (IARC) indicates the following chemicals are “also relevant: 38641-94-0 (glyphosate-isopropylamine salt) 40465-66-5 (monoammonium salt) 69254-40-6 (diammonium salt) 34494-03-6 (glyphosate-sodium) 81591-81-3 (glyphosate-trimesium)” (IARC, 2015b), because these salts dissociate to free glyphosate.
Footnotes and References
 The Safe Drinking Water and Toxic Enforcement Act of 1986, Health and Safety Code, section 25249.5, et seq.
Monsanto et al v OEHHA et al., Fresno County Superior Court case #16CECG00183, recently appealed to the California Court of Appeal (5th District). A case number has not yet been assigned.
 International Agency for Research on Cancer (IARC, 2006). Preamble. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. World Health Organization, Lyon, France
 Health and Safety Code section 25249.10, Title 27, Cal. Code of Regs., section 25701 et seq.
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