Roundup Ruling: Supreme Court Blocks State’s Failure-to-Warn Claim for EPA-Approved Pesticide Labels

By Sara M. Ajeti and Sean M. Sherlock

On June 25, 2026, the U.S. Supreme Court resolved a longstanding circuit split in Monsanto Co. v. Durnell, holding that the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) expressly preempts state law claims for failure to provide warnings beyond those approved and required by the Environmental Protection Agency (EPA).

In 2019, John Durnell sued Monsanto in Missouri state court, alleging that approximately 20 years of using the glyphosate-based herbicide Roundup caused his non-Hodgkin’s lymphoma. The case traces to a 2015 finding by the World Health Organization’s International Agency for Research on Cancer that glyphosate is “probably carcinogenic to humans.” EPA has maintained that glyphosate is “not likely to be carcinogenic to humans” and has never required a cancer warning on Roundup’s label.

FIFRA requires EPA to approve a pesticide’s label by determining that it contains all warnings “necessary and…adequate to protect health and the environment” and no “false or misleading” statements. Manufacturers must use that approved label, as deviation can trigger civil and criminal penalties. Because EPA has concluded that glyphosate is not likely to cause cancer and has not required a cancer warning, Monsanto was required to use its EPA-approved label without the cancer warning. The Court held that a state tort verdict based upon the failure to provide a cancer warning would impose a labeling requirement “in addition to” and “different from” FIFRA’s requirements – precisely what the preemption clause bars.

The Court was unpersuaded by Durnell’s counterarguments. First, Durnell argued Missouri’s failure-to-warn standard merely requires “adequate warnings to protect human health,” which parallels FIFRA. The Court found this approach too general because it disregards EPA’s specific regulatory determinations and would nullify the preemption clause.

Second, Durnell challenged EPA’s registration procedures as exceeding its statutory authority under FIFRA. The Court disagreed, noting FIFRA expressly empowers EPA to prescribe regulations to carry out the Act and to determine label compliance.

Third, Durnell invoked a provision of FIFRA which states registration is not a defense for the commission of any offense under FIFRA. See 7 U.S.C. § 136a(f)(2). The Court reasoned that this provision only clarifies that registration does not bar federal enforcement for FIFRA offenses. Reading it to upend FIFRA’s structure would be “bizarre” and expose manufacturers to massive liability for using EPA-required labels.

Fourth, Durnell raised concerns about new safety information arising after registration. The Court found this was addressed by FIFRA’s post-registration tools, including mandatory adverse-effects reporting, EPA authority to request data and commission reviews, and third-party petitions to modify or cancel registration.

Monsanto v. Durnell reshapes the litigation landscape for companies whose products bear federally approved labels. Notably, several federal statutes governing meat, poultry, food, dietary supplements, cosmetics, and medical devices contain similar labeling-preemption provisions. While this ruling provides meaningful certainty on FIFRA preemption, its application to other regulatory schemes will depend on statute-specific analysis and the degree to which the relevant agency affirmatively approves label content. Companies should assess how their agency approvals interact with state tort exposure and develop proactive strategies accordingly.