Hunton Retail Law Resource

On June 25, 2026, the Supreme Court held in Monsanto Co. v. Durnell that the Federal Insecticide, Fungicide, and Rodenticide Act (“FIFRA”) preempts state law failure-to-warn claims that would require a manufacturer to add or modify warnings EPA-approved warnings on pesticide labels.  This decision is the culmination of decades of product liability litigation alleging that the popular Roundup herbicide was carcinogenic and lacked sufficient warning labels under state tort laws. While this decision will likely close the book on the Roundup litigation, it also has important implications for any manufacturers that produce products subject to federal regulation under FIFRA.  

The Durnell decision is centered on Roundup, a glyphosate-based herbicide manufactured by Monsanto (a subsidiary of Bayer AG) which is one of the most widely used pesticide products on the market.  Roundup is subject to FIFRA, and its labels are directly regulated by EPA. Over the course of multiple decades, EPA has repeatedly evaluated glyphosate and consistently concluded that it is “not likely to be carcinogenic to humans” and, therefore, has never required a cancer warning on Roundup’s label.  Regulators around the globe have reached similar conclusions.  However, in 2015, the International Agency for Research on Cancer, a working group under the World Health Organization, classified glyphosate as “probably carcinogenic to humans,” precipitating a tidal wave of litigation.  These suits have predominantly asserted failure-to-warn claims under state tort law and allege that Roundup causes cancer and that the product’s label should have included a cancer warning.  

In this case, plaintiff John Durnell sued in Missouri state court in 2019, alleging that his use of Roundup caused him to develop non-Hodgkin’s lymphoma and that Monsanto failed to warn consumers about that risk by omitting a cancer warning on the label.  A jury returned a verdict in Durnell’s favor, awarding him $1.25 million in damages.  Monsanto argued that the claim was preempted by FIFRA because it would require a label different from the one approved by EPA.  The trial court and Missouri Court of Appeals rejected that argument, holding that FIFRA did not preempt the claim.  The Supreme Court granted review to resolve a circuit split on the issue.  

In a 7-2 decision, the Supreme Court reversed the judgment of the Missouri Court of Appeals, holding that “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,” – a violation of FIFRA’s preemption provision.  That provision ensures “uniformity” in labeling by prohibiting states from imposing “any requirements for labeling or packaging in addition to or different from” those required by FIFRA.  As the Court emphasized, the preemption provision’s express references to “uniformity” reflected Congress’ intent to establish a single, national labeling standard.  Once EPA approves a label, that label must be used unless and until EPA authorizes a change and amends the product’s registration.  The Court concluded that a state law duty for Monsanto to add a cancer warning to Roundup’s label would impose a requirement “in addition to or different from” those “required under FIFRA.”  The majority opinion drew an analogy to the Court’s earlier decision in Riegel v. Medtronic, Inc., 552 U.S. 312 (2008), which had interpreted a similar preemption clause in the Medical Device Amendments Act of 1976 to bar state-law claims imposing additional or conflicting safety requirements following FDA approval. The Court reasoned that “[i]f FDA's premarket approval of medical devices preempted additional state-law requirements, so too must EPA's registration of pesticides and approval of pesticide labels.”  Allowing Durnell's claim to proceed would have implications beyond FIFRA, as "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." 

The Court’s decision in Durnell will fundamentally reshape the ongoing litigation over Roundup, with thousands of those claims based on failure-to-warn theories now facing potential dismissal.  More broadly, the decision could have significant implications for entities operating in other regulated spaces, such as pharmaceuticals and medical devices, where federally approved safety labels can potentially clash with state-level failure-to-warn claims.  As the Court’s reliance on the Reigel decision makes clear, federal regulatory regimes containing preemption provisions comparable to the language in FIFRA may provide the basis for similar preemption defenses, though the analysis remains statute-specific.   

Under Durnell, manufacturers may be able to assert a preemption defense to other common state level suits that impose further warning requirements on products regulated by FIFRA. For example, California’s highly litigated Proposition 65 requires the ubiquitous warnings that many products contain “chemicals known to the State of California to cause cancer and birth defects or other reproductive harm.”  In many cases, components in FIFRA-regulated pesticides are regulated by Proposition 65 and therefore require warnings under California law. Courts may find that this warning requirement is “in addition to or different from” the federal requirements under FIFRA and is therefore preempted. The defense bar has an especially strong argument insofar as plaintiffs allege a failure to add Proposition 65 warnings to product labels. Consequently, Defendants may now have an opportunity to strategically layer preemption arguments onto their substantive defenses. 

At the same time, the decision may also contribute to increased efforts by the plaintiffs’ bar to develop alternative theories of liability for cases involving both the pesticides industry and other similarly regulated industries.  Under the reasoning of Durnell, state tort claims sounding in negligence, strict liability, or other theories that do not impose “additional or different” labeling requirements - such as claims alleging defective product design, manufacturing defects, or failure to conduct adequate testing – would fall outside of the preemption provision, potentially making them more viable than traditional failure-to-warn claims.  However, plaintiffs’ abandonment of failure-to-warn causes of action limits their strategic options, and these alternative claims are generally subject to other defenses or limitations. For example, the jury in Durnell actually rejected plaintiffs’ design defect and negligence claims. Similarly, claims challenging representations made in marketing or promotional claims that go beyond the content of an agency-approved label would not be subject to preemption.  This change in state tort theories of liability may require a comparable evolution in product liability defenses and regulatory management.