In 2017, the California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment (OEHHA) listed glyphosate and three other common pesticides as “known to the state to cause cancer”.

This followed the decision by the World Health Organization’s International Agency for Research on Cancer (IARC) to classify glyphosate (found in the commonly-used pesticide Roundup) as a “probable carcinogen.” California law requires the state’s Office of Environmental Health Hazard Assessment to list substances identified by IARC as known to cause cancer under the state’s Proposition 65.