The United States Supreme Court recently issued a 7-2 decision in Monsanto v. Durnell, holding that state‑law failure‑to‑warn claims related to pesticide labeling are expressly preempted by the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). The case arose after John Durnell, a longtime Roundup user diagnosed with non‑Hodgkin’s lymphoma, sued Monsanto in Missouri state court, alleging the company failed to warn consumers about cancer risks. Monsanto argued that FIFRA preempted such claims because federal law requires manufacturers to use EPA‑approved labels—and Roundup’s label, repeatedly reviewed and approved by the EPA since 1974, contains no cancer warning.
Justice Kavanaugh’s majority opinion emphasized FIFRA’s “uniformity” clause, which prohibits states from imposing labeling requirements “in addition to or different from” federal requirements. Because Mr. Durnell’s failure-to-warn claim would require Monsanto to add a cancer warning not included on the EPA‑approved label, the Court held the claim constituted an additional labeling requirement and was therefore preempted. The majority relied heavily on the fact that this was a safety claim, and during the registration process, the EPA thoroughly reviews all safety-related issues. The majority stressed that EPA’s label approval reflects its determination that the label is not misleading and contains all necessary warnings; allowing states to impose additional requirements would undermine FIFRA’s regulatory structure.
Justice Thomas concurred but questioned FIFRA’s constitutionality, arguing Congress exceeded its Commerce Clause authority and improperly delegated legislative power to the EPA. He also seemed to question whether agriculture in general could be regulated pursuant to the Commerce Clause.
Justice Jackson, joined by Justice Gorsuch, dissented. The dissent believed Mr. Durnell’s claim was equivalent to FIFRA’s misbranding standard, not “different from” it. Because EPA had not set specific cancer‑related warning requirements, she contended that Missouri’s failure‑to‑warn law merely duplicated federal obligations. The dissent emphasized that registration is only prima facie evidence of compliance and does not eliminate the possibility that a registered pesticide may still be misbranded. Jackson also rejected implied preemption, noting Monsanto could comply with both federal and state law by halting sales or seeking EPA approval for a revised label.
To read a more detailed summary, click here.
Recommended citation format: Lashmet, Tiffany Dowell. “United States Supreme Court Holds Roundup Failure to Warn Claims Preempted by Federal Law.” Southern Ag Today 6(29.5). July 17, 2026. Permalink
