Supreme Court Holds FIFRA Preempts State Failure-to-Warn Claims Challenging EPA-Approved Pesticide Labels

On June 25, 2026, the U.S. Supreme Court issued its landmark decision in Monsanto Co. v. Durnell, No. 24-1068, resolving a circuit split over whether the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) preempts state law failure-to-warn claims challenging EPA-approved pesticide labels. In a 7-2 opinion, the Court held that FIFRA expressly preempts state tort claims that would require a manufacturer to add or modify warnings on a pesticide label, at least where the U.S. Environmental Protection Agency (EPA) has evaluated the relevant risk and approved the label, whether with warnings reflecting the agency’s assessment or without a corresponding warning.

The decision is the most significant development in pesticide tort litigation in decades. It establishes that EPA’s product-specific registration and label-approval determinations carry preemptive force under FIFRA’s preemption clause, 7 U.S.C. § 136v(b), shielding manufacturers from tort liability predicated on the theory that an EPA-approved label should have said something more or different to warn of a safety risk.

For pesticide manufacturers, Durnell provides a powerful new tool to seek early dismissal of failure-to-warn claims, but the strength of the preemption defense will depend on the depth and specificity of EPA’s review of the particular risk at issue. Manufacturers should ensure robust documentation of EPA’s consideration of relevant health and environmental hazards during the registration and re-registration process. At the same time, the decision does not immunize manufacturers from all state law exposure: claims grounded in product design defects, manufacturing defects, advertising and promotional representations, and potentially also environmental or health risks that EPA did not affirmatively evaluate remain viable avenues for plaintiffs seeking to recover for claimed injuries under state tort law.

Background and Context

Monsanto manufactures and distributes Roundup, a widely used glyphosate-based herbicide. Throughout the product’s registration history, EPA has repeatedly evaluated glyphosate’s carcinogenic potential and consistently concluded that glyphosate is “not likely to cause cancer.” Accordingly, EPA has registered glyphosate-based pesticides without requiring a cancer warning on the label. Despite EPA’s carcinogenicity determination, thousands of plaintiffs have brought state law failure-to-warn claims against Monsanto, alleging that Roundup causes cancer and that the product’s label should have included a cancer warning. Courts were sharply divided on whether FIFRA preempts such claims: the U.S. Court of Appeals for the Third Circuit held that it does, while the U.S. Courts of Appeals for the Ninth Circuit and Eleventh Circuit, as well as several state courts, held that it does not.

In 2019, John Durnell sued Monsanto in Missouri state court, alleging that his use of Roundup caused him to develop cancer and that Monsanto failed to warn users by omitting a cancer warning from the label. A jury returned a verdict for Durnell and awarded more than $1 million in damages. Monsanto argued that the claim was preempted by FIFRA because it would require a label different from the one EPA had approved. The Missouri trial court and the Missouri Court of Appeals rejected that argument, holding that the state’s failure-to-warn duties were “fully consistent with” FIFRA. The Supreme Court granted certiorari to resolve the circuit split.

The Court’s Holding

In a 7-2 decision authored by Justice Kavanaugh, the Court held that FIFRA expressly preempts state law failure-to-warn claims that would require a pesticide manufacturer to add or alter a warning on a label that EPA has reviewed and approved. The ruling establishes that EPA’s registration and label-approval determinations carry preemptive force, foreclosing tort liability predicated on the absence of warnings that EPA considered and declined to require, or on the alleged inadequacy of warnings that EPA reviewed and approved.

The decision centers on FIFRA’s preemption clause, 7 U.S.C. § 136v(b), which prohibits states from imposing labeling or packaging requirements “in addition to or different from” those required under FIFRA. The Court held that the federal labeling “requirements” triggering preemption are not limited to the statutory text and EPA regulations in the abstract. Rather, EPA’s product-specific registration determinations, including its evaluation of health risks and its approval of a particular label, constitute binding federal requirements that trigger preemption.

The Court grounded that conclusion in the structure of FIFRA’s registration scheme. Before registering a pesticide, EPA must determine that the proposed label contains all warnings “necessary and adequate to protect health and the environment” and includes no “false or misleading” statement under the misbranding provision, 7 U.S.C. § 136(q)(1)(A), (G). In the Court’s view, registration thus represents the agency’s considered judgment that the label’s warnings are sufficient — and once EPA approves a label, the manufacturer must only use that label unless and until EPA approves or requires a modification.

Applying that framework, the Court concluded that Durnell’s claim was squarely preempted. EPA had repeatedly evaluated glyphosate’s carcinogenic potential, consistently concluded that glyphosate is “not likely to cause cancer,” and approved Roundup’s label without a cancer warning on multiple occasions. Because the Missouri failure-to-warn claim would effectively require Monsanto to add a cancer warning that EPA had specifically considered and declined to require, it imposed a state labeling obligation “in addition to” and “different from” federal law. The Court rejected Durnell’s counterarguments, including that Missouri tort law merely parallels FIFRA’s misbranding standard, reasoning that this argument “operates at far too high a level of generality” and disregards EPA’s central role in making labeling determinations.

Practical Implications of the Court’s Decision

• Manufacturers whose EPA-approved labels have undergone agency review of the relevant risk can now invoke Durnell to seek early dismissal of state law failure-to-warn claims challenging the absence or inadequacy of warnings.
• The strength of a manufacturer’s preemption defense may turn on the depth and specificity of EPA’s review of the relevant risk during the registration and re-registration process. While some language in Justice Kavanaugh’s majority opinion indicates that all attempts to modify or add to an EPA-approved label must fail, other parts of the decision rely heavily on EPA’s assessment of cancer risk. Comprehensive documentation of EPA’s consideration of a given hazard thus may be critical to establishing preemption in future litigation.
• The decision will likely redirect litigation toward theories that do not depend on imposing additional or different labeling obligations, as discussed further below.

Continued Exposure to Non-Label-Based Claims

Notwithstanding the breadth of the Court’s holding, Durnell does not foreclose all state law claims against pesticide manufacturers. Claims that do not depend on imposing labeling or packaging requirements remain viable, and claims that involve environmental or health risks EPA did not affirmatively consider during registration also might survive. Several categories of claims are likely to survive:

• Efficacy-based claims. The Court reaffirmed the distinction drawn in Bates v. Dow Agrosciences LLC between safety claims — which EPA thoroughly reviews at registration — and efficacy claims, which EPA does not review as part of the registration process. Because EPA’s approval of a pesticide label “does not reflect any determination on the part of EPA that the pesticide will be efficacious,” state tort claims challenging a label’s efficacy representations — such as claims that a pesticide failed to perform as described on the label — are not preempted.
• Negligence and strict liability claims not predicated on labeling. State tort claims sounding in negligence, strict liability, or other theories that do not depend on the content of the pesticide’s label — such as claims alleging defective product design, manufacturing defects, or failure to conduct adequate testing — are not labeling requirements and therefore fall outside the preemption clause.
• Advertising and promotional claims. Claims challenging representations made in marketing materials or promotional campaigns beyond the EPA-approved label (e.g., that a product is “safe” or “non-toxic”) are not labeling requirements subject to preemption.
• Proposition 65 and analogous state disclosure regimes. To the extent a Proposition 65 claim would require adding a cancer warning to an EPA-approved label that lacks one, it is likely preempted. However, obligations that attach to point-of-sale notices, website disclosures, or other communications that do not appear on the label and are not distributed with the product itself likely fall outside § 136v(b). This distinction is likely to be tested in future litigation.
• Claims involving safety risks EPA did not consider. The Court’s reasoning depends on EPA’s having affirmatively evaluated the relevant risk. Where a state law claim is premised on a safety risk that EPA neither considered nor addressed in its labeling determination, there is a plausible argument that no federal requirement exists to trigger preemption. The Court did not squarely resolve this question, and future litigation will likely test its boundaries.

Durnell will reshape the landscape of pesticide tort litigation, and its full implications for pending cases, regulatory strategy, and state enforcement actions will only become clear over time. Crowell & Moring’s Environmental and Litigation teams are available to assist clients in assessing the impact of the Court’s decision and navigating the evolving legal framework.