The Supreme Court of the United States recently issued an opinion restricting the scope of state law failure-to-warn claims for pesticide products. In Monsanto Co. v. Durnell, No. 24-1068, 609 U.S. ___ (2026), the Supreme Court held that a specific federal law, the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), preempts state law. The Court’s 7-2 opinion reversed and remanded a state court case that had awarded $1 million to a plaintiff on the theory that a pesticide should have included a cancer warning on its labeling.
What is FIFRA?
FIFRA is a federal law governing, among other things, the registration and labeling of pesticide products. In order to register a pesticide product, the U.S. Environmental Protection Agency (EPA) must approve the pesticide’s label by determining that the label contains all warnings “necessary and . . . adequate to protect health and the environment” and that the label does not include any “false or misleading” statements. 7 U.S.C. §§136a(c)(5)(B), 136(q)(1)(A), (G). After EPA approves a pesticide’s label at registration, manufacturers are legally required to use that label unless and until EPA approves or requires a label change and amends the pesticide’s registration. See id. §136a(f)(1); 40 CFR §§152.44(a), 156.70(c).
FIFRA also provides for preemption of state laws, requiring that a state “shall not impose or continue in effect any requirements for labeling or packaging in addition to or different from those required under [FIFRA].” 7 U.S.C. §136v(b).
What is this case about?
The underlying case in Durnell was one of many cases alleging that a glyphosate pesticide product was required to include a cancer warning on its labeling. At issue here was the labeling of Roundup, a glyphosate pesticide product first registered in 1974. For decades, the EPA has repeatedly reevaluated Roundup and approved the product’s labeling without a cancer warning.
Durnell began in Missouri state court in 2019. The plaintiff alleged he had used Roundup for more than 20 years and had subsequently developed non-Hodgkins’s lymphoma, a type of cancer. The plaintiff further alleged that the company had failed to warn consumers of purported cancer risks resulting from Roundup. The case was tried to a jury, resulting in a verdict of $1 million in the plaintiff’s favor.
The Missouri trial court, and later a state appellate court, rejected the company’s preemption arguments. The Missouri courts held that FIFRA did not preempt the failure-to-warn claims because both the federal and state law were consistent—both required a pesticide manufacturer to adequately warn users of the potential dangers of using the product.
What did the Court decide?
By a 7-2 majority, the Court held FIFRA does preempt state law claims. The Court reasoned that after EPA approves a pesticide’s label at registration, manufacturers are legally required to use that label—unless and until EPA approves or requires a label change and amends the pesticide’s registration. If a manufacturer does not use the EPA-approved label, it may be subject to civil and criminal penalties. Here, EPA approved—and subsequently reapproved—the labeling without the cancer warning. The Court concluded that the company was required to use this labeling. The Missouri plaintiff’s claim would, by contrast, mandate the company to add the cancer warning to the labeling—a result the Court concluded would be “different from” the obligations under federal law.
In a 24-page dissent, Justices Ketanji Brown Jackson and Neil Gorsuch argued that the majority’s opinion “unjustifiably closes the courthouse doors to state court plaintiffs like Durnell.” In dissent, the justices argued that EPA’s registration and approval of a label under FIFRA does not preclude a company from adding a warning, like the cancer warning at issue here.
What are the implications?
The Court recognized that the Durnell case was part of a split among the nation’s federal courts of appeal and state courts as to whether FIFRA preempts state failure-to-warn claims on pesticide labels. With its opinion, the Court has conclusively resolved the division among courts, greatly strengthening the preemption defense available to pesticide manufacturers under FIFRA.
