Atrazine, Propazine, Simazine and their Chlorometabolites DACT, DEA And DIA Listed as Reproductive Toxicants

Effective October 1, 2015, December 14, 2015 [listing delayed pending the court ruling on Syngenta’s Request for a Temporary Stay in Syngenta v OEHHA (Third District Court of Appeal case# C082128)] the Office of Environmental Health Hazard Assessment (OEHHA) is adding atrazine, propazine, simazine, des-ethyl atrazine (DEA), des-isopropyl atrazine (DIA) and 2,3-diamino-6-chloro-s-triazine (DACT)* to the list of chemicals known to the state to cause reproductive toxicity for purposes of Proposition 651.

The listing of these six chemicals is based on formal identification by the US Environmental Protection Agency (US EPA), an authoritative body2, of these six chemicals as causing reproductive toxicity (developmental and female reproductive endpoints).  The criteria used by OEHHA for the listing of chemicals under the “authoritative bodies” mechanism can be found in Title 27, Cal. Code of Regs., section 25306.

The documentation supporting OEHHA’s determination that the criteria for administrative listing have been satisfied for atrazine, propazine, simazine, DACT, DEA, and DIA is included in the Notice of Intent to List posted on OEHHA’s website and published in the February 7, 2014 issue of the California Regulatory Notice Register (Register 2014, No. 6-Z). OEHHA received nine public comments on the Notice of Intent to List. The comments and OEHHA’s responses are posted with the Notice of Intent to List.

In summary, these six chemicals are being listed under Proposition 65 effective October 1, 2015 as known to the State to cause reproductive toxicity, as follows:



Toxicological Endpoints

Listing Mechanism







Developmental toxicity
Female reproductive toxicity










Des-ethyl atrazine (DEA)


Des-isopropyl atrazine (DIA)


2,3-Diamino-6-chloro-s-triazine (DACT)*


Footnotes and References

* Note: DACT was incorrectly identified as 2,3-diamino-6-chloro-s-triazine (instead of 2,4-diamino-6-chloro-s-triazine). That typographical error will be corrected when the chemicals are ultimately added to the list.

 Listing mechanism: AB – “authoritative bodies” mechanism (Title 27, Cal. Code of Regs. section 25306).

1 The Safe Drinking Water and Toxic Enforcement Act of 1986, Health and Safety Code section 25249.5 et seq.

2 See Health and Safety Code, section 25249.8(b) and Title 27, Cal. Code of Regs., section 25306.