On June 25, 2026, the Supreme Court issued a 7-2 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 premised on a pesticide manufacturer's failure to include a cancer warning on its label. The Court held that FIFRA's express preemption clause bars such claims when the EPA has registered the pesticide and approved its label without requiring a cancer warning. Justice Kavanaugh delivered the opinion of the Court, joined by Chief Justice Roberts and Justices Thomas, Alito, Sotomayor, Kagan, and Barrett. Justice Jackson dissented, joined by Justice Gorsuch.
Background
FIFRA requires pesticide manufacturers to register their products with the EPA and obtain EPA approval of the product label before sale. After registration, manufacturers must use the EPA-approved label and may not change it without further agency approval, under penalty of civil and criminal sanctions.[i] FIFRA's "Uniformity" preemption clause provides 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 this subchapter."[ii]
The Monsanto Company manufactures and distributes Roundup, an herbicide that has historically been glyphosate-based.[iii] Since approving Roundup’s registration in 1974, the EPA has consistently concluded that it is not likely to cause cancer in humans.[iv] The agency has accordingly never required glyphosate-based products to carry a cancer warning.
Procedural History
In 2019, John Durnell filed suit against Monsanto in Missouri state court, alleging that approximately 20 years of Roundup use had caused his non-Hodgkin's lymphoma. His central claim was a failure-to-warn tort, contending that Monsanto should have included a cancer warning on Roundup's label. A jury agreed and awarded Durnell $1.25 million in damages. Monsanto moved for judgment notwithstanding the verdict, arguing that FIFRA preempted the claim. Both the trial court and the Missouri Court of Appeals rejected this argument, reasoning that Missouri's failure-to-warn standard was "fully consistent" with FIFRA's misbranding prohibition because both ultimately require adequate warnings to protect users. The Supreme Court granted certiorari to resolve a split among federal circuits and state courts.
The parties' dispute before the Supreme Court centered on what constitutes a federal labeling "requirement" under FIFRA. Monsanto argued that EPA's registration and label approval (affirmatively determining that no cancer warning was necessary) created a binding federal requirement that preempted any contrary state-law obligation. Durnell countered primarily on four grounds:
- Missouri's failure-to-warn standard simply requires adequate warnings to protect human health, a standard functionally equivalent to FIFRA's own misbranding prohibition, and therefore adds nothing "in addition to or different from" federal law;
- EPA's regulations, and its procedures for registering pesticides and approving pesticide labels, exceed or contravene the agency's statutory authority under FIFRA;
- 7 U.S.C. § 136a(f)(2) provides that registration "shall not be construed as a defense for the commission of any offense" under FIFRA, meaning EPA's approval of a label cannot itself create a preemptive federal requirement; and
- FIFRA's existing mechanisms cannot adequately address regulatory lag concerns without resorting to state tort law.
Supreme Court Analysis
The Court began by confirming, consistent with Bates v. Dow Agrosciences LLC, 544 U.S. 431 (2005), that state tort duties constitute labeling "requirements" subject to preemption. It then asked whether Durnell's claim imposed a requirement "in addition to or different from" federal requirements "under" FIFRA.
The answer, in the majority's view, was plainly yes. Given that EPA regulations require manufacturers to use the approved label and prohibit label changes without agency authorization, the EPA-approved Roundup label without a cancer warning is the operative federal requirement. A state tort claim compelling Monsanto to add a cancer warning is therefore "in addition to" and "different from" what federal law mandates. The Court found support in Riegel v. Medtronic, Inc., 552 U.S. 312 (2008), where it held that FDA premarket approval under a materially identical preemption clause displaced additional state-law requirements for medical devices.
The Court then addressed Durnell's counterarguments. On the equivalence argument, the Court concluded that framing both Missouri law and FIFRA as simply requiring "adequate warnings" operated at too high a level of generality and disregarded EPA's comprehensive and specific role in the registration process; FIFRA's preemption clause extends to requirements imposed "under" FIFRA, not merely those stated in the bare text of the statute. The statutory-authority argument fared no better: the Court reasoned that FIFRA expressly empowers the agency to issue regulations carrying out the statute's provisions and directs it to determine whether a pesticide's labeling complies with FIFRA's requirements, making EPA's registration and label-approval process a valid exercise of that delegated authority.
Turning to § 136a(f)(2), the Court held the provision inapplicable to state tort suits, reasoning that it merely clarifies that registration does not bar the EPA from bringing its own enforcement actions. In any event, Monsanto was not invoking the bare fact of registration as a defense, but rather EPA's specific determination that no cancer warning was required. Finally, on regulatory lag, the Court determined that FIFRA's existing mechanisms—including manufacturer reporting obligations, EPA monitoring authority, and citizen petition rights—were sufficient to address evolving safety information without resort to state tort liability.
Concurrence
Justice Thomas joined the majority opinion in full but wrote separately to highlight what he described as "underlying constitutional infirmities" in FIFRA itself, arguing that the statute exceeds Congress's Commerce Clause authority. He also questioned whether Congress may constitutionally vest the EPA with the authority to issue labeling regulations backed by criminal penalties, which he characterized as the exercise of core legislative power, and raised doubts about whether agency action can ever carry preemptive force under a Supremacy Clause that makes only the Constitution, federal law, and treaties supreme.
Dissent
Justice Jackson, joined by Justice Gorsuch, dissented. In her view, the majority misidentified the relevant federal "requirement." The real requirement, she argued, is FIFRA's ongoing misbranding prohibition rather than the specific content of any EPA-approved label. Section 136a(f)(2) confirms as much, because it provides that registration cannot preclude a subsequent misbranding finding, meaning the approved label and the statutory requirement are not coextensive. As Missouri's failure-to-warn standard parallels the misbranding prohibition, the dissent concluded it adds nothing "in addition to or different from" what FIFRA already demands. She further argued that the majority's approach cannot be squared with Bates, where the Court's remand for further assessment of whether the claims were equivalent to the misbranding standard would have been unnecessary if EPA label approval itself carried preemptive force.
Observations
End of the Roundup Litigation Wave
Monsanto v. Durnell resolves a circuit split and effectively forecloses the primary theory of liability pursued in the thousands of Roundup cases filed over the past decade. Failure-to-warn claims seeking cancer warnings on EPA-registered pesticide labels are categorically preempted. Manufacturers facing similar pending claims, whether in state or federal court, will have strong grounds for dismissal.
Broader Implications for Regulatory Preemption
The decision extends Riegel's logic from FDA medical device approval to EPA pesticide registration, signaling that analogous conclusions may follow wherever a federal statute combines a similar approval regime with a similarly worded preemption clause. Multiple federal labeling statutes, covering food, consumer products, and other regulated items, contain nearly identical language. Regulated industries operating under comparable federal approval schemes will likely invoke Monsanto v. Durnell in preemption arguments moving forward.
[i] 7 U.S.C. §§ 136j(a)(1)(E), 136l
[ii] 7 U.S.C. § 136v(b)
[iii] Monsanto has phased out residential glyphosate Roundup products and now sells multiple formulations of herbicides falling under the Roundup brand that do not contain glyphosate. Read our article on recent changes to Roundup formulations at Roundup: It's Not What it Used to Be! | Yard and Garden.
[iv] Although this determination is shared by multiple regulatory bodies across Canada, Australia, Japan, and the European Union, not all scientific bodies have reached the same conclusion; in 2015, the International Agency for Research on Cancer (IARC) classified glyphosate as a probable human carcinogen.