Episode 37 · October Term 2025 · September 1, 2026 · 00:35:38

Monsanto v. Durnell

The Court holds that the Federal Insecticide, Fungicide, and Rodenticide Act expressly preempts a state-law failure-to-warn claim that would require a pesticide manufacturer to add a cancer warning to a label EPA has approved without one. Because federal law requires Monsanto to use the EPA-approved Roundup label unless and until EPA approves or requires a change, a Missouri tort claim demanding a different label imposes a requirement "in addition to or different from" FIFRA's.

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Case
Monsanto v. Durnell
Author
Justice Kavanaugh
Docket
24-1068
Decided
2026-06-25
Opinion
Read on supremecourt.gov →

Case background

Monsanto Company manufactures and distributes Roundup, a glyphosate-based herbicide designed to control weeds. EPA has repeatedly evaluated glyphosate and repeatedly concluded that it is not likely to cause cancer in humans, an assessment shared by many other regulatory bodies around the world, and has accordingly never required a cancer warning on the labels of glyphosate-based pesticides like Roundup. In 2019, John Durnell sued Monsanto in Missouri state court, alleging that he had used Monsanto’s Roundup products for about 20 years and that they had caused his non-Hodgkin’s lymphoma. As relevant here, Durnell brought a failure-to-warn tort claim asserting that Monsanto should have included a cancer warning on Roundup’s label. A jury agreed and awarded him more than $1 million on that theory, and the Missouri Court of Appeals affirmed, rejecting Monsanto’s argument that FIFRA expressly preempted the claim. This Court granted certiorari to resolve a division among the federal courts of appeals and state appellate courts over whether FIFRA preempts such claims.

Questions Presented

(1) Whether FIFRA preempts a state-law failure-to-warn claim where EPA has repeatedly concluded that the warning is not required and the warning cannot be added to a product without EPA approval.

Holding

FIFRA expressly preempts Durnell’s state-law failure-to-warn claim because the claim would require Monsanto to add a cancer warning to Roundup’s label. FIFRA’s preemption clause, entitled “Uniformity,” bars a State from imposing any labeling or packaging requirement “in addition to or different from” those required under the Act. To register a pesticide, EPA must approve its label by determining that the label contains all warnings “necessary and . . . adequate to protect health and the environment” and no “false or misleading” statements; once approved, the manufacturer is legally required to use that label unless and until EPA approves or requires a change. Because state tort duties constitute state labeling requirements, Durnell’s claim, which would compel a warning EPA has not required, is in addition to and different from Monsanto’s federal-law labeling obligations. Riegel v. Medtronic, Inc., which addressed the materially identical preemption clause of the Medical Device Amendments of 1976, confirms that conclusion. Reversed and remanded.

The Court

Justice Kavanaugh delivered the opinion of the Court, in which Chief Justice Roberts and Justices Thomas, Alito, Sotomayor, Kagan, and Barrett joined. Justice Thomas filed a concurring opinion. Justice Jackson filed a dissenting opinion, in which Justice Gorsuch joined.

What this episode contains

This episode is an AI-narrated reading of the majority opinion in Monsanto v. Durnell, written by Justice Kavanaugh.

AI disclosure: The voice in this episode is AI-generated, using a machine learning model styled to loosely resemble the authoring justice. Tone, inflection, pacing, and emphasis are artifacts of the model and should not be attributed to Justice Kavanaugh. The text being read is the Court’s published majority opinion, lightly adapted to improve readability for the spoken format.