Published February 18, 2026 · Parkinson's Lawsuit Help
Defendants in pesticide litigation routinely argue that state-law failure-to-warn claims are preempted by the federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). Whether they win that argument depends on subtle distinctions that the Supreme Court has addressed in successive cases. Monsanto v. Durnell, which the Court took up in the Roundup litigation, has direct implications for paraquat.
What FIFRA preemption is
FIFRA governs how pesticides are labeled in the United States. Defendants argue that if the EPA approved a label, state-law claims that the label was inadequate are preempted — a federal-label-equals-state-immunity argument. Plaintiffs counter that EPA approval is a regulatory floor, not a tort-law ceiling, and that state law can impose additional duties consistent with federal labeling.
The Bates framework
In Bates v. Dow Agrosciences (2005) the Supreme Court held that state-law claims are preempted only when they impose a labeling requirement that is "in addition to or different from" what FIFRA requires. Parallel state-law duties survive preemption. The line between "parallel" and "in addition to" is where these cases are fought.
Where Durnell fits
Monsanto v. Durnell tests how aggressively defendants can use FIFRA to shut down failure-to-warn claims. Whatever the Court ultimately decides will be applied by analogy in paraquat — Chevron and Syngenta will argue for the broadest preemption reading possible.
Practical implications for paraquat plaintiffs
A more aggressive preemption ruling would not eliminate paraquat claims — most paraquat cases also include design defect and negligence theories that do not depend on label inadequacy. But it would narrow some claims and could affect settlement valuations. The lesson: file early and preserve the strongest theories of liability.
Get a free case review
If you or a family member were exposed to paraquat and have been diagnosed with Parkinson's disease, request a free case review. It takes 15 to 30 minutes by phone, costs nothing, and locks in your place while settlement options remain open. Check eligibility or call (717) 724-7503.