On June 25, 2026, the United States Supreme Court issued a significant preemption decision in Monsanto Co. v. Durnell, holding that the Federal Insecticide, Fungicide, and Rodenticide Act (“FIFRA”) preempts state-law failure-to-warn claims that would require cancer warnings on Roundup’s label beyond those approved by the U.S. Environmental Protection Agency (“EPA”). In a 7-2 opinion by Justice Kavanaugh, the Court reversed a Missouri judgment awarding more than $1 million to plaintiff John Durnell, who alleged that Monsanto’s Roundup caused his cancer and should have included a cancer warning.

FIFRA requires pesticides to be registered with EPA. During registration, EPA reviews both the product and its proposed label and must determine that the pesticide will not generally cause unreasonable adverse effects on human health or the environment. EPA also must find that the label includes all necessary and adequate warnings and is not false or misleading. Once EPA approves a label, the manufacturer must use it unless EPA authorizes a change, or be potentially subject to enforcement.

EPA has repeatedly reviewed glyphosate-based pesticides, like Roundup, and has consistently concluded that glyphosate is not likely to cause cancer in humans, maintaining that position after the International Agency for Research on Cancer classified glyphosate as a probable carcinogen. As a result, EPA never required a cancer warning on Roundup’s label.

Plaintiff John Durnell alleged that roughly twenty years of Roundup use caused him to develop non-Hodgkin’s lymphoma. He asserted that Monsanto failed to warn him of Roundup’s risks and should have included a cancer warning on the product’s label. A Missouri jury awarded him more than $1 million on that theory.

The Supreme Court granted review to resolve a split among federal and state courts over whether FIFRA preempts label-based failure-to-warn claims when EPA has not required the warning at issue. The Court held that it does. Specifically, FIFRA’s preemption clause, titled “Uniformity” bars States from imposing “any requirement for labeling or packaging in addition to or different from those required under” FIFRA.

Relying on prior precedent, the Court first reaffirmed that state tort duties, including those underlying Durnell’s claim, qualify as state labeling “requirements” because they effectively set standards for product labels. The Missouri judgment was therefore deemed to require Monsanto to add a cancer warning that differed from the EPA-approved label Monsanto was federally required to use. The Court concluded that this was precisely what FIFRA’s preemption clause forbids. The majority also emphasized Congress’s stated objective of “Uniformity,” reasoning that national consistency would be impossible if individual States or juries could mandate warnings different from those approved by EPA.

The Court also relied on Riegel v. Medtronic, Inc., which interpreted a nearly identical preemption clause in the Medical Device Amendments of 1976. In Riegel, the Court held that FDA premarket approval of medical devices preempted state-law claims based on additional or conflicting safety requirements. The majority concluded that EPA-approved pesticide labels should receive similar treatment under FIFRA.

The decision has significance beyond FIFRA litigation as it provides a useful roadmap for express preemption analysis. The majority focused on statutory text, regulatory structure, and Congress’s express goal of uniformity, while treating agency-approved labeling as a federal requirement capable of preempting conflicting state-law duties. Those principles may be important in future cases involving other federal regulatory schemes with similar preemption provisions.

Share | Email| Print| Comments|  Topics: EPA, Federal Insecticide, Fungicide, and Rodenticide Act, FIFRA, Supreme Court, Toxic Torts, United States Supreme Court