U.S. Supreme Court Rules FIFRA Expressly Preempts State Failure-to-Warn Claims in Roundup Litigation

On June 25, 2026, the Supreme Court issued its opinion in Monsanto Co. v. Durnell, No. 24-1068, 609 U.S. __ (U.S. June 25, 2026), reversing the Missouri Court of Appeals and holding that the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) expressly preempts state-law failure-to-warn claims that would compel pesticide manufacturers to add a cancer warning to an EPA-approved label. The 7-2 majority opinion, authored by Justice Kavanaugh and joined by Chief Justice Roberts and Justices Thomas, Alito, Sotomayor, Kagan, and Barrett, resolves a split among the federal circuits and state courts in the Roundup litigation. It also provides important guidance on express preemption that should help to bar or narrow state-law product liability claims across other regulated industries.

Background

FIFRA vests the EPA with comprehensive authority over pesticide registration and labeling. Before registering a pesticide, EPA undertakes an extensive review of its proposed label, determining that it contains “all warnings necessary and adequate to protect human health and the environment, and is not false or misleading.” Durnell, slip op. at 4 (citing 7 U.S.C. §§ 136a(c)(5)(B), 136(q)(1)(A), (G)). After EPA approves a label at registration, the manufacturer is legally required to use that label and may not alter it without EPA’s prior approval. Id. Deviating from the EPA-approved label exposes the manufacturer to civil and criminal penalties for misbranding. Id. (citing 7 U.S.C. §§ 136j(a)(1)(E), 136l). FIFRA also contains an express preemption clause titled “Uniformity,” prohibiting States “from imposing ‘any requirements for labeling or packaging in addition to or different from those required under’ FIFRA.” Id. at 6 (quoting 7 U.S.C. § 136v(b)).

Monsanto manufactures Roundup, a glyphosate-based herbicide first registered by EPA in 1974. Since 1991, EPA has repeatedly evaluated glyphosate and consistently concluded that it is not likely to cause cancer in humans. Id. at 6-7. Accordingly, EPA has not required a cancer warning on Roundup’s label, and federal law therefore requires Monsanto to sell Roundup without one. Id. at 7. Notwithstanding EPA’s determination, the International Agency for Research on Cancer (IARC) classified glyphosate as “probably carcinogenic to humans” in 2015, triggering tort litigation.

In 2019, John Durnell sued Monsanto in Missouri state court, alleging that Roundup use caused his non-Hodgkin’s lymphoma and that Monsanto was liable for failure to warn. Id. at 8. A jury awarded him more than $1 million. Id. The trial court denied Monsanto’s preemption motion for judgment notwithstanding the verdict, and the Missouri Court of Appeals affirmed. Id.

Federal and state courts have been divided over the Roundup preemption question. Compare Schaffner v. Monsanto Corp., 113 F.4th 364 (3d Cir. 2024) (claims preempted), with Carson v. Monsanto Co., 92 F.4th 980 (11th Cir. 2024) and Hardeman v. Monsanto Co., 997 F.3d 941 (9th Cir. 2021) (claims not preempted). The Supreme Court granted certiorari to resolve the conflict. Durnell, slip op. at 9.

The Court’s Analysis

The Court and parties agreed that “state tort duties constitute state labeling requirements” for preemption purposes. Durnell, slip op. at 9. The dispositive question was whether Durnell’s state-law failure-to-warn claim, “which would require a cancer warning on the Roundup label,” imposed a requirement “in addition to or different from” what FIFRA requires. Id. The Court held the answer was plainly yes. Id. Federal law requires Monsanto to use the EPA-approved label, without a cancer warning. Durnell’s claim would require Monsanto to add one. That state requirement is thus both “in addition to” and “different from” federal labeling obligations and therefore expressly preempted.  Id. at 11; see also id. at 14, 22.

The Court found dispositive support in Riegel v. Medtronic, Inc., 552 U.S. 312 (2008), which addressed the materially identical preemption clause in the Medical Device Amendments of 1976. In Riegel, the Court held that FDA’s premarket approval of a medical device imposed federal “requirements” that preempted state-law safety claims. 552 U.S. at 322-25. The same logic applied in Durnell: just as FDA’s premarket approval process preempts state tort claims that would impose different safety requirements for medical devices, EPA’s registration and label approval process preempts state tort claims requiring different warnings for pesticides. Durnell, slip op. at 13, 15.

The Court also noted that this logic extends to other federal statutes regulating “a range of industries” that “contain similar or identical labeling preemption provisions.” Id. at 13. The Court specifically cited comparable preemption statutes governing over-the-counter drugs (21 U.S.C. § 379r(a)(2)), cosmetics (21 U.S.C. § 379s(a)), food nutrition labeling (21 U.S.C. §343-1(a)(2)-(4)), and meat and poultry products (21 U.S.C. §§ 678, 467e). Id. As the Court explained, “[t]hose similar labeling preemption clauses reflect Congress’s judgment that the ability to sell a product throughout the country with a single label can be important to maintaining an efficient nationwide market.” Id. at 13-14.

The Court rejected each of Durnell’s counterarguments. The Court held that Durnell’s argument that his Missouri failure-to-warn claim does not impose requirements that differ from FIFRA’s because both state and federal law share a general standard of adequate warnings relied on “far too high a level of generality” and ignored EPA’s specific, binding labeling determinations. Id. at 14-15. The Court also rejected as “implausibl[e]” Durnell’s argument that EPA’s pesticide registration and labeling determinations lack “preemptive force.” Id. at 15. Similarly, the Court rejected Durnell’s challenge to EPA’s regulatory authority, confirming that “FIFRA expressly directs EPA to register pesticides and ‘determin[e]’ that the pesticide’s ‘labeling’ complies with FIFRA’s many specific requirements.” Id. at 16 (quoting 7 U.S.C. § 136a(c)(5)(B)).  

Next, the Court held that Durnell’s reliance on a FIFRA provision that pesticide registration is not a “defense” to an EPA enforcement action, 7 U.S.C. § 136a(f)(2), was flawed for multiple reasons, including because the provision is limited to EPA enforcement and “does not apply to state tort suits.” Durnell, slip op. at 16. Beyond that threshold defect, “Durnell’s § 136a(f)(2) argument would negate FIFRA’s express preemption clause, expose manufacturers to potentially massive tort liability for doing what EPA required them to do, and eviscerate the ‘uniformity’ of EPA’s labeling determinations.” Id. at 18-19 (citing 7 U.S.C. §§ 136a(f)(2), 136v(b)). Finally, the Court addressed Durnell’s policy concerns about the potential for a “regulatory lag” between new safety information and an EPA review and label change. Id. at 20. The Court pointed to FIFRA’s and EPA’s “comprehensive regulatory regime” to “address new safety information,” including through ongoing safety monitoring, manufacturer disclosures, third-party citizen petitions for EPA review, and judicial review of EPA decisions. Id. at 20-21.

The Court reversed the Missouri Court of Appeals’ judgment and remanded. Id. at 22. Because the Court found Durnell’s failure-to-warn claim expressly preempted, it did not address whether the claim was also barred by the doctrine of implied preemption. Id. at 14 n.7.

Justice Thomas concurred in full but wrote separately to raise three constitutional concerns with FIFRA’s regulatory scheme: whether the statute’s scope exceeds Congress’s Commerce Clause authority; whether Congress has impermissibly delegated legislative authority to EPA; and whether federal agency action qualifies as “supreme Law of the Land” under the Supremacy Clause for preemption purposes. These are not holdings, but they may preview future challenges to preemption arguments.

Justice Jackson, joined by Justice Gorsuch, dissented. Like Durnell, the dissent argued that FIFRA does not preempt Durnell’s state-law claims because the state-law claims parallel FIFRA’s misbranding prohibition. The dissent also argued that FIFRA’s registration process does not impose “requirements” that have preemptive effect and that § 136a(f)(2) establishes that EPA registration and labeling approval cannot serve as a complete defense. Finally, the dissent argued that implied preemption, or preemption based on the impossibility of complying with both federal and state law requirements, did not apply because, according to the dissent, federal law permitted Monsanto to add a cancer warning without first obtaining EPA approval. 

Practical and Strategic Takeaways

Durnell has important implications for product liability litigation, federal regulatory preemption doctrine, and risk management. The following points highlight the decision’s key practical and strategic implications and identify where the law is likely to continue to develop. 

Failure-to-warn claims should not proceed in the Roundup litigation. For the thousands of glyphosate personal injury cases pending in federal and state courts, Durnell should bar plaintiffs’ cornerstone failure-to-warn theory.

Durnell supports preemption challenges to other state-law pesticide safety claims. Durnell provides additional controlling support for motions to dismiss or summary judgment in other litigations with safety or warnings-based state-law claims involving FIFRA-regulated and EPA-registered pesticides. The Court held that “when it comes to safety claims, EPA’s registration determinations do reflect EPA’s considered judgment that a pesticide’s label is not false or misleading and contains all necessary warnings. So safety claims that would impose labeling requirements ‘in addition to’ or ‘different from’ those required under FIFRA are preempted.” Durnell, slip op. at 12.  

Other regulated industries with express preemption statutes should benefit. The majority emphasized that other federal statutes contain preemption clauses “similar or identical” to FIFRA’s and that its analysis applies across those regimes. Durnell, slip op. at 13. Companies subject to comprehensive federal labeling schemes, including in the medical device, pharmaceutical, food, and consumer product sectors, should evaluate regulatory and litigation opportunities and strategies in light of this decision.

Agency activities are likely to receive heightened attention. The Court’s discussion of EPA’s regulatory and enforcement tools for addressing safety concerns may lead to additional scrutiny of agency decisions and an increase in administrative and citizen petition activity.

The concurrence and dissent identify legal theories to monitor. While Justice Thomas’s constitutional observations did not draw additional votes, they may generate future challenges in a variety of legal areas, including challenges related to the nondelegation doctrine and the scope of the Supremacy Clause. Similarly, the dissent’s statutory construction and implied preemption arguments are likely to continue to be raised in litigation and legislative debate around the scope and application of federal preemption.