EPA Prohibits Proposition 65 Warnings for Glyphosate on Pesticide Labeling

August 13, 2019

Last week, the U.S. Environmental Protection Agency (EPA) sent a letter to manufacturers reaffirming its conclusion that glyphosate is "not likely to be carcinogenic to humans" and prohibiting pesticide labeling from bearing California Proposition 65 (Prop 65) cancer warnings regarding glyphosate. In EPA's interpretation, these warnings would be false and misleading to users and, therefore, contrary to the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA).

Since pesticide labeling includes product labels and related informational and marketing materials, Prop 65 warnings will be prohibited from most communications pertaining to these products. Manufacturers have 90 days to submit amended labeling removing any Prop 65 warnings.

Yesterday, the California Office of Environmental Health and Hazard Assessment (OEHHA) responded to EPA's criticism, objecting to the characterization of Prop 65 warnings as false claims.

In February 2018, the U.S. District Court for the Eastern District of California issued a preliminary injunction allowing California to add glyphosate to the Prop 65 list but prohibiting enforcement of the Prop 65 warning requirement. However, OEHHA has used its new website to distribute a fact sheet about glyphosate.

OEHHA's 2017 listing of glyphosate under Prop 65 was based on an assessment by the International Agency for Research on Cancer (IARC) that glyphosate is "probably carcinogenic to humans." EPA disagrees with IARC's assessment.

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