2x Higher risk of developing Parkinson’s disease for people exposed to paraquat, per studies reviewed by the EPA. The agency has been conducting a formal registration review since 2016.
What Vermont Did
On May 26, 2026, Governor Phil Scott signed H.739, making Vermont the first U.S. state to ban paraquat. The ban takes full effect on December 31, 2030, giving Vermont farmers four years to transition to alternatives.
The lead time is intentional. Paraquat is still widely used in commercial agriculture, particularly on soybeans, corn, and orchards. Vermont’s law signals to farmers that the transition is coming while giving them time to adjust.
What Paraquat Is
Paraquat is a broad-spectrum herbicide used to kill weeds before planting and to dry crops before harvest. It is one of the most widely applied agricultural chemicals in the United States. It is also one of the most acutely toxic. A single sip can be fatal, and there is no antidote.
The chronic health concern is different from the acute one. Decades of research have linked long-term paraquat exposure to Parkinson’s disease, a progressive nervous system disorder that destroys dopamine-producing cells. The risk is highest for farmworkers who apply it directly, and for people who live near treated fields and are exposed through drift or groundwater.
What the Evidence Shows
The EPA has been reviewing paraquat under its registration review process since 2016. Its own science reviews have found the Parkinson’s link compelling enough to warrant continued examination. Studies reviewed by the agency show exposure approximately doubles the risk of developing the disease.
More than 32 countries have reached their own conclusions. The European Union banned paraquat in 2007. The United Kingdom, China, and Brazil followed. The United States remains one of the few major agricultural nations still permitting its commercial use, at a restricted level requiring licensed applicators.
Syngenta and Chevron, the primary manufacturers, face thousands of Parkinson’s disease lawsuits from farmworkers and people who lived near treated fields. The litigation has not produced a federal ban.
Why the EPA Has Not Acted
The EPA’s registration review process is legally required to evaluate whether a pesticide continues to meet safety standards. For paraquat, the process has been open for a decade. The agency completed a preliminary risk assessment in 2019 but has not finalized its determination.
Pesticide manufacturers have significant influence over EPA review timelines through the comment process and litigation. The agency can cancel a registration under the Federal Insecticide, Fungicide, and Rodenticide Act when it finds unreasonable adverse effects. It has not done so for paraquat.
The current administration has moved to roll back other EPA environmental and health protections. A proactive paraquat ban under this EPA is unlikely without congressional pressure.
What You Can Do
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Demand an EPA paraquat ban. The EPA has the authority under federal law. Congress can direct that authority. Send the letter above →
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If you work in agriculture or live near treated fields, the Parkinson’s Foundation maintains research on occupational exposure risk. The United Farm Workers tracks pesticide safety advocacy.
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Watch other states. Vermont’s model law gives farmers a four-year transition period. States with large agricultural sectors (California, Iowa, Nebraska) face the same tradeoffs and could follow Vermont’s path. The Pesticide Action Network tracks state-level activity.
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Read the Environment and Public Lands hub for the full scope of EPA rollbacks and environmental protections under pressure since January 2025.