California Bans Paraquat Herbicide, Phasing Out 14 Million Pounds Over 2 Years
Updated
Updated · The Guardian · Aug 13
California Bans Paraquat Herbicide, Phasing Out 14 Million Pounds Over 2 Years
3 articles · Updated · The Guardian · Aug 13
Summary
California’s pesticide regulator canceled the state’s last paraquat registration, starting a two-year phaseout of a herbicide used on millions of acres and making California the second US state to prohibit it.
A 2024 state law forced a fresh risk review, and DPR said its preliminary findings linked paraquat to human health harms including Parkinson’s associations, thyroid disease, reproductive harms and birth defects.
Syngenta, the biggest supplier, withdrew its California permit in April and said it would stop producing paraquat altogether rather than provide updated health and environmental data sought by regulators.
About 14 million pounds of paraquat are sprayed annually on US crops, with California the country’s biggest user; DPR also found risks to birds and mammals and warned the chemical can persist in soil for decades.
The move adds pressure on the EPA, which reapproved paraquat in 2021 and 2024 and still faces an Earthjustice-led lawsuit accusing it of ignoring scientific evidence linking the herbicide to Parkinson’s disease.
With California banning this highly toxic weedkiller, will the rest of the nation finally follow suit or face a growing health crisis?
Could California's sudden ban on this controversial herbicide trigger a massive surge in food prices as farmers scramble for costly alternatives?
California’s Paraquat Ban: Timeline, Legal Battles, and the National Push to End Use of a Deadly Herbicide
Overview
California’s phase-out of paraquat began after the passage of AB 1963, which required a formal reevaluation of the herbicide. When manufacturers chose to cancel their registrations instead of submitting new safety data, the state initiated a two-year transition period. This move was accelerated by a major spill in March 2026, which led to public outcry and calls for a ban. At the same time, decades of research linking paraquat to Parkinson’s disease fueled thousands of lawsuits and pressured Syngenta to halt global production. Vermont’s ban and similar state efforts, along with federal legislative proposals, are now shaping a patchwork of regulations across the country.