Preemption: Why the Supreme Court Rejected a Roundup Jury Verdict

On June 25, 2026, the United States Supreme Court issued a much-awaited decision in Monsanto v. Durnell. The Court, in a 7-2 vote, overturned a jury verdict for the plaintiff, holding a federal law that regulates pesticides preempted plaintiffs’ state law claims.

The legal question boiled down to whether plaintiffs could bring a “failure to warn” claim against Monsanto based on Missouri state law, when federal law and the EPA did not require a cancer warning label on Roundup, a glyphosate-based herbicide. The EPA has repeatedly found that glyphosate is not likely to cause cancer, so it does not require a cancer warning on Roundup. Thousands of plaintiffs around the county have sued Monsanto, alleging that Roundup caused them to develop cancer. The case before the Supreme Court came from Missouri, where a groundskeeper alleged that years of spraying Roundup caused his non-Hodgkins lymphoma. He argued that Monsanto was liable under a failure-to-warn theory because, he said, the company should have included a cancer warning on the product. A state court jury agreed with him and awarded $1,000,000. The Supreme Court eventually accepted the case and now has ruled that the Federal Insecticide Fungicide and Rodenticide Act (FIFRA) preempts state law failure-to-warn cases.

The EPA requires a pesticide manufacturer such as Monsanto to use the EPA-approved pesticide label—here, the Roundup label without a cancer warning—unless and until EPA approves or requires a different label. The FIFRA statute includes a “uniformity” clause, which prohibits States from imposing any pesticide labeling requirements that are “in addition to or different from” the federal labeling requirements under FIFRA. The Court explained that the plaintiff’s state tort claim would require Monsanto to add a cancer warning to Roundup’s label even though federal law requires Monsanto to use the EPA-approved label without a cancer warning. Because the plaintiff’s claim would impose a pesticide labeling requirement “in addition to or different from” the label required by EPA, the Court concluded that FIFRA expressly preempted his claim.

The Court traced the history of federal pesticide regulation all the way back to President Truman. After several legislative updates, the current statutory regime constitutes a “comprehensive regulatory statute” giving the EPA increased enforcement authority.” EPA’s registration of the pesticide and approval of the pesticide’s label embodies the agency’s judgment that a pesticide is not misbranded—that is, that the label is not false or misleading and does not omit a necessary warning. After EPA has registered the pesticide and approved the label, the manufacturer is required to use that label. In a section called “uniformity,” FIFRA provides that a state may not require a label that is “in addition to or different from” the EPA-approved one.

The plaintiff argued that the cancer warning would be consistent with the EPA-approved label because FIFRA simply requires manufacturers to include adequate warnings to protect human health, and not to include false or misleading statements. Plaintiff also suggested the EPA’s labeling regulations went beyond the power granted to the agency by Congress through FIFRA. The Supreme Court rejected the plaintiff’s argument as being far too general (and inaccurate), noting that plaintiff’s state tort argument would require Monsanto to add a cancer warning to its labels. That state requirement would be “in addition to” and “different from” Monsanto’s federal-law labeling obligations and is therefore preempted by federal law. The Court also pointed out that this case involved safety claims (preempted) rather than efficacy claims (possibly not preempted since EPA’s labeling review is not based on product efficacy).

This decision will have an immediate impact on cases throughout the country, as the decision addresses a “circuit split” where our federal appeals courts have split on whether FIFRA preempts state law failure-to-warn claims based on the failure to include a cancer warning on Roundup. The case is also likely to be cited to by state and federal courts everywhere as Monsanto v. Durnell sets forth a strong statement of federal preemption and describes the hierarchical relationship between federal and state law. Indiana likewise has a robust body of preemption decisions from our appellate courts describing the power balance between state and local law.