California is banning paraquat, a controversial and highly toxic herbicide. The state's Department of Pesticide Regulation (DPR) announced on Tuesday that it had cancelled the remaining paraquat pesticide registrations, with a two-year phase-out period.
Public health advocates describe paraquat as a deadly substance that is virtually proven to cause Parkinson’s disease. It is already outlawed in over 70 countries, including China, the UK, and the EU.
The decision follows a 2024 state law that required regulators to re-review paraquat’s risks. A preliminary DPR review confirmed human health concerns, including associations between paraquat exposure and thyroid disease, reproductive harms, and birth defects. The DPR also found potential risks to birds and mammals.
Pesticide makers, including Syngenta, decided to stop using the substance in California rather than sharing updated health and environmental risk data requested by the DPR. Syngenta, which made the largest amount of the pesticide, withdrew its use permit in April and announced it would stop producing the substance entirely.