What Is Paraquat?
Paraquat dichloride is an herbicide that the EPA says is highly toxic to humans, that one small accidental sip can be fatal, and that there is no antidote. The EPA says all paraquat products registered in the United States are Restricted Use Pesticides that may only be used by trained certified applicators, and that its July 2021 interim decision finalized new, stronger protections to reduce exposure.
On Parkinson's disease, the EPA says that after a thorough review of the best available science, it has not found a clear link between paraquat exposure from labeled uses and adverse health outcomes such as Parkinson's disease and cancer.
In federal court, an April 2024 order in the paraquat multidistrict litigation in the Southern District of Illinois described more than 5,000 plaintiffs who allege they developed Parkinson's disease because of paraquat exposure. In that order the court granted the defendants summary judgment in four cases and dismissed them with prejudice. A later court order records that on September 3, 2025, plaintiffs' co-lead counsel and the defendants executed a master settlement agreement for certain individual claims involving paraquat products.
Sources checked September 15, 2026. Every point below links the page it came from.
The sources behind this answer
- Regulatory filingThe EPA says all paraquat products registered in the United States are Restricted Use Pesticides that may only be used by trained certified applicators. US EPA ↗
- Government sourceThe EPA says paraquat is highly toxic to humans, that one small accidental sip can be fatal, and that there is no antidote. US EPA ↗
- Regulatory filingThe EPA released its paraquat interim decision in July 2021 and says it finalizes new, stronger protections to reduce exposure to paraquat. US EPA ↗
- Government sourceThe EPA says that after a thorough review of the best available science it has not found a clear link between paraquat exposure from labeled uses and adverse health outcomes such as Parkinson's disease and cancer. US EPA ↗
- Legal caseIn an April 2024 order, the federal court handling the paraquat multidistrict litigation said over 5,000 plaintiffs allege they developed Parkinson's disease because of exposure to paraquat dichloride. US District Court for the Southern District of Illinois, MDL No. 3004 ↗
- Legal caseIn an order filed April 17, 2024, the court granted the defendants' joint motion for summary judgment and dismissed four cases against Syngenta AG and others with prejudice. US District Court for the Southern District of Illinois, MDL No. 3004 ↗
- Legal caseA case management order records that on September 3, 2025, plaintiffs' co-lead counsel and the defendants executed a Master Settlement Agreement for certain individual claims involving paraquat products. US District Court for the Southern District of Illinois, MDL No. 3004 ↗
Sources checked September 15, 2026. A brand statement is the company’s own claim, which we report but have not verified. Our grades are model-based estimates, not lab tests.