Roundup Preemption Case Throws Uncertainty Into Paraquat Settlement Negotiations
More than 8,000 people who say they developed Parkinson’s disease after years of paraquat exposure have been waiting for their lawsuits to be resolved. Now, it looks like they might have to wait even longer.
A mass Paraquat settlement seemed likely when both sides signed an agreement in April 2025, showing they were working to resolve many of the claims. After that, the judge in charge of the main group of paraquat cases delayed setting trial dates and put the evidence-gathering process on hold. This pause has been extended several times, and the latest extension is set to end next month.
But now, Syngenta, the company that makes paraquat, has filed a new motion asking the court to dismiss the state failure-to-warn claims. The company is using the same federal preemption arguments that came up in the Roundup weed killer lawsuits, which are now going to the U.S. Supreme Court.
The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) requires companies to get Environmental Protection Agency approval for their pesticide labels before selling them. After approval, labels usually cannot be changed without the EPA’s permission.
Syngenta says that since the EPA-approved paraquat labels do not warn about Parkinson’s, and the agency has repeatedly found the evidence too weak to prove a link, state claims seeking such a warning should not be allowed.
The Roundup Connection
The U.S. Supreme Court recently agreed to hear Durnell v. Monsanto Co., a case from the Roundup lawsuits that directly asks whether FIFRA blocks state failure-to-warn claims about EPA-approved pesticide labels.
Federal appeals courts disagree on this issue. The Third Circuit says these claims are blocked, but the Ninth and Eleventh Circuits have ruled the other way.
In their court filing, the paraquat defendants focus on the Third Circuit’s decision and highlight the Solicitor General’s view that FIFRA blocks labeling claims that would require more than what the EPA has approved. They have asked the court to either rule in their favor now or wait until the Supreme Court makes its decision, expected later this year.
Paraquat Settlement Implications
This preemption issue comes at a sensitive time in the paraquat MDL. As mentioned earlier, the lawsuits have been in long settlement talks involving thousands of claims.
Most of these cases involve failure-to-warn allegations. If the court dismisses these claims on preemption grounds, the lawsuits could narrow substantially.
Even if the court waits for the Supreme Court’s decision, the uncertainty could affect how both sides assess their risks and the likelihood of settling.
A Supreme Court ruling in Monsanto’s favor could provide strong authority for dismissing similar labeling claims in the paraquat MDL. Conversely, if the Court rejects the preemption defense, plaintiffs’ leverage in both litigations could increase significantly.
A Broader Federalism Question
At its heart, this dispute shows the ongoing conflict between federal regulatory power and state law.
The EPA has reviewed the science on paraquat and Parkinson’s disease several times and decided the evidence does not justify changing the label. But plaintiffs say juries should be allowed to review the evidence for themselves under state law.
The EPA still allows paraquat to be used in the United States, but more than 70 countries have banned it. The United States imports tens of millions of pounds of paraquat each year, even from countries that do not allow it within their own borders.
Several studies have found a link between paraquat exposure and a higher risk of Parkinson’s, including research showing that people who apply it or live near treated fields are more likely to be diagnosed with the progressive brain disorder.
Earlier this year, the EPA said that manufacturers must now prove that current uses of paraquat are safe in real-world conditions. This shows that the agency is still reviewing the chemical’s safety.
As court battles continue and federal regulators reassess the science, a growing number of states are considering legislation to restrict or ban paraquat use entirely or near schools.
The Supreme Court’s decision in the Roundup case will not settle the scientific debate about paraquat. But it will decide who has the authority to say if a warning was needed.
If the Court says federal approval protects manufacturers from state failure-to-warn claims, juries may have much less say in these lawsuits. If not, the paraquat cases could go to trial and settlement talks could pick up again.
For the thousands of families waiting for answers, what happens next may depend less on the science and more on how the Supreme Court decides the balance between federal rules and state responsibility.
