ARTICLE
1 July 2026

Supreme Court Holds Roundup Failure-To-Warn Claim Preempted By Federal Law

MB
Mayer Brown

Contributor

Mayer Brown is an international law firm positioned to represent the world’s major corporations, funds, and financial institutions in their most important and complex transactions and disputes.
The Supreme Court ruled 7-2 that federal pesticide law preempts state tort claims requiring cancer warnings on Roundup's label when the EPA has not mandated such warnings. This decision resolves a circuit split over whether manufacturers must follow state common-law duties or federal labeling requirements when they conflict.
United States Litigation, Mediation & Arbitration
Andrew J. Pincus’s articles from Mayer Brown are most popular:
  • with readers working within the Chemicals industries
Mayer Brown are most popular:
  • within Compliance topic(s)

Monsanto Co. v. Durnell, No. 24-1068

Today, the Supreme Court held in a 7-2 decision that the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) preempts a state-law tort claim alleging that Monsanto should have added a cancer warning to Roundup’s label.

Background

John Durnell sued Monsanto in Missouri state court, alleging that he developed cancer as a result of using the glyphosate-based pesticide Roundup. His failure-to-warn claim alleged that Monsanto had a duty to include a cancer warning on Roundup’s label. A jury agreed with Durnell and awarded him $1.25 million in damages. Monsanto then argued that FIFRA preempted Durnell’s tort suit, because EPA had concluded that glyphosate is unlikely to cause cancer and declined to require a cancer warning on Roundup’s label. The trial court rejected that preemption argument, and the Missouri Court of Appeals affirmed. The Supreme Court granted certiorari to resolve a conflict among the lower courts over whether FIFRA preempts state-law tort claims challenging Roundup’s omission of a cancer warning.

Issue

Whether FIFRA preempts a label-based failure-to-warn claim where EPA has not required the warning.

Court’s Holding

In an opinion authored by Justice Kavanaugh and joined by Chief Justice Roberts and Justices Thomas, Alito, Sotomayor, Kagan, and Barrett, the Supreme Court held that FIFRA expressly preempts Durnell’s Missouri failure-to-warn claim.

FIFRA provides that no state may “impose or continue in effect any requirements for labeling or packaging in addition to or different from those required under” the statute. 7 U.S.C. § 136v(b). FIFRA authorizes EPA to issue regulations, and EPA exercised that authority to impose labeling requirements on Roundup. But the Roundup label approved by EPA does not contain a cancer warning. Relying on the FIFRA provision’s express preemption of state-law labeling requirements, the Court held that Monsanto must use the EPA-approved label unless and until EPA approves a different one.

The Court reasoned that Durnell’s claims were based on common-law rules that effectively are labeling requirements. Because those claims “set a standard for a product’s labeling,” the Court explained, they are preempted if they require a label to include content “in addition to or different from” that required by FIFRA. And the Court concluded that Durnell’s Missouri failure-to-warn claim did exactly that—it “would require Monsanto to add a cancer warning to its labels,” whereas “federal law requires Monsanto to sell Roundup” using “the label without a cancer warning.” The Court feared that “’[u]niformity’ in labeling—the textually stated objective of FIFRA’s preemption clause—would . . . be impossible to achieve” if the claim were not preempted.

The Court rejected Durnell’s argument that “a Missouri failure-to-warn claim, like FIFRA itself, simply requires manufacturers to include adequate warnings to protect human health, and not to include false or misleading statements.” That argument, the Court explained, “operates at far too high a level of generality,” because the proper focus of the preemption inquiry is on “the specific requirements imposed” by EPA regulations. The Court also rejected the argument that “EPA’s regulations—and its procedures for registering pesticides and approving pesticide labels—exceed or contravene EPA’s statutory authority under FIFRA,” pointing to FIFRA’s broad language empowering EPA to “prescribe regulations to carry out” the statute. 7 U.S.C. § 136w(a)(1).

The Court distinguished failure-to-warn claims based on safety (like Durnell’s) from claims targeting efficacy. Citing Bates v. Dow Agrosciences LLC, 544 U.S. 431 (2005), the Court said that efficacy-based failure-to-warn claims would not be preempted because EPA does not review a pesticide’s efficacy during the registration process.

Justice Thomas filed a short concurring opinion suggesting that portions of FIFRA may be unconstitutional on federalism and separation-of-powers grounds.

Justice Jackson dissented, joined by Justice Gorsuch. She maintained that “[t]he majority reads into FIFRA a labeling requirement that does not exist, and it reads out of FIFRA the statute’s ongoing prohibition on misbranding,” thereby “unjustifiably clos[ing] the courthouse doors to state tort plaintiffs like Durnell.”

Visit us at mayerbrown.com

Mayer Brown is a global services provider comprising associated legal practices that are separate entities, including Mayer Brown LLP (Illinois, USA), Mayer Brown International LLP (England & Wales), Mayer Brown (a Hong Kong partnership) and Tauil & Chequer Advogados (a Brazilian law partnership) and non-legal service providers, which provide consultancy services (collectively, the "Mayer Brown Practices"). The Mayer Brown Practices are established in various jurisdictions and may be a legal person or a partnership. PK Wong & Nair LLC ("PKWN") is the constituent Singapore law practice of our licensed joint law venture in Singapore, Mayer Brown PK Wong & Nair Pte. Ltd. Details of the individual Mayer Brown Practices and PKWN can be found in the Legal Notices section of our website. "Mayer Brown" and the Mayer Brown logo are the trademarks of Mayer Brown.

© Copyright 2026. The Mayer Brown Practices. All rights reserved.

This Mayer Brown article provides information and comments on legal issues and developments of interest. The foregoing is not a comprehensive treatment of the subject matter covered and is not intended to provide legal advice. Readers should seek specific legal advice before taking any action with respect to the matters discussed herein.

[View Source]

Mondaq uses cookies on this website. By using our website you agree to our use of cookies as set out in our Privacy Policy.

Learn More