Monsanto v. Durnell

​Poulsen Law P.C. | June 25, 2026

 

The Supreme Court handed Bayer the kind of decision the company's lawyers had been quietly drafting in their dreams for the better part of a decade. By a vote of 7-2, the Court ruled in Monsanto Co. v. Durnell, No. 24-1068, that the Federal Insecticide, Fungicide, and Rodenticide Act expressly preempts state-law failure-to-warn claims when EPA has approved a pesticide's label without a cancer warning. Justice Kavanaugh wrote for the majority. Justice Thomas concurred, with a side note questioning what he sees as FIFRA's constitutional architecture. Justice Jackson dissented, joined by Justice Gorsuch — a pairing that should be carved into a stone tablet for future bar-exam questions on the unpredictability of preemption doctrine.

​

The judgment below — the Missouri Court of Appeals' affirmance of a $1.25 million jury verdict for John Durnell, the St. Louis "spray guy" diagnosed with non-Hodgkin lymphoma after two decades of weed-killing without protective gear — was reversed and remanded. And with that reversal, Bayer's $7.25 billion class-action settlement framework, preliminarily approved in March, suddenly has the cleanest possible runway to final approval at the hearing scheduled in Missouri state court in early July.

What the Court Actually Held

The holding is narrower than the press release writers will make it sound, and broader than the plaintiffs' bar would like.

​

Section 136v(b) of FIFRA is titled "Uniformity," and the Court took the title seriously. The 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." The majority's logic moves in four steps. First, EPA approves a pesticide's label at registration after determining that the label is not "false or misleading" and contains all "necessary and adequate" warnings. Second, manufacturers are legally required to use the EPA-approved label "unless and until EPA approves or requires a label change." Third, under Bates v. Dow Agrosciences LLC, 544 U.S. 431, 443–44 (2005), state tort duties constitute "labeling requirements" for FIFRA purposes.

​

Fourth, Durnell's claim would require Monsanto to add a cancer warning EPA never approved and has, in fact, several times declined to require. That, in Justice Kavanaugh's words, "is 'in addition to' and 'different from' Monsanto's federal-law labeling obligations." Preempted.

​

The opinion leans on Riegel v. Medtronic, Inc., 552 U.S. 312 (2008), to do most of the analytic work. Riegel held that the FDA's premarket approval of medical devices imposed "requirements" that preempted state-law tort claims under the materially identical preemption clause of the Medical Device Amendments. The majority calls Riegel "dispositive." If FDA's premarket approval of a pacemaker preempts a state-law jury's verdict that the warnings were inadequate, then EPA's registration of a herbicide does too. The structural symmetry is genuinely hard to argue with, which is presumably why the majority kept returning to it.

​

What the Court did not do is also worth flagging. The majority expressly limited its analysis to express preemption ("Because we conclude that Durnell's failure-to-warn claim is expressly preempted, we need not consider Monsanto's implied preemption argument"). It did not address design-defect claims. It did not address state-law claims grounded in § 136v(a), which preserves state authority to "regulate the sale or use" of pesticides — siting restrictions, application restrictions, use restrictions. It did not address pesticides EPA has not registered, or labels EPA has not approved, or warnings EPA has expressly refused to approve after being asked. It did not touch the Bates "efficacy claims" lane, which remains open because EPA does not review efficacy at registration. The holding is about safety-based labeling claims that would require a warning EPA's registration regime has not adopted. That is a very specific lane. It is also the lane in which most of the past decade's Roundup verdicts have lived.

Justice Jackson's Dissent: The Best Argument the Plaintiffs' Bar Will Get for a While

Justice Jackson's dissent, joined by Justice Gorsuch, is sharp, structurally elegant, and worth reading in full. Her core move is to take Bates literally. Bates held that FIFRA preempts state requirements that are "in addition to or different from" FIFRA's requirements, but does not preempt state requirements that are equivalent to FIFRA's. Jackson identifies FIFRA's central labeling requirement as the misbranding prohibition in § 136j(a)(1)(E) and the "adequate" and "necessary" warnings requirement in § 136(q)(1)(G). Missouri's failure-to-warn standard, she argues, simply parallels those federal requirements. A state jury finding that the label was inadequate is functionally a finding that the label was misbranded under federal law. That is parallel, not additional.

​

The most damaging point in the dissent — at least to the practical real-world coherence of the majority's reasoning — is this: EPA itself, on at least one occasion involving Roundup, approved a label, then later concluded the approved label did not comply with FIFRA's misbranding prohibition, and imposed civil penalties on Monsanto for distributing the very labels EPA had approved. Justice Jackson uses this to argue that EPA registration is "prima facie evidence" of FIFRA compliance — not conclusive evidence — and that a manufacturer can be "registered but nevertheless misbranded." That is straight out of Bates at p. 438. Her conclusion: the majority "reads into FIFRA a labeling requirement that does not exist, and it reads out of FIFRA the statute's ongoing prohibition on misbranding."

She also throws an elbow at the impossibility-of-compliance theory: Monsanto, she notes, can "easily comply with both federal and state law by stopping sales of Roundup." A market exit option, she suggests, defeats any obstacle-preemption inference.

​

The dissent will be cited in every post-Durnell state-law product-liability brief in the country involving a federally registered product. It will not win those cases. But it will frame them.

Justice Thomas, Writing Separately

Justice Thomas joined the majority in full and added a concurrence flagging what he describes as constitutional infirmities in FIFRA itself. The concurrence is — characteristically — a longer view than the case in front of him required. It is also a flare to the bar: if a challenger ever wanted to argue that FIFRA's delegation to EPA, or some other structural feature of the statute, is constitutionally suspect, there is at least one Justice already pre-disposed to entertain that question.

What This Means in California

For California Prop 65 practice — and for those of us who watch federal preemption land mines for a living — the immediate question is whether Durnell migrates beyond FIFRA. The short answer is: not automatically, but the reasoning will be deployed.

​

Durnell is FIFRA-specific. Prop 65 warning requirements are not labeling requirements imposed by a state under FIFRA's specific preemption clause; they are stand-alone state-law warning duties under California Health and Safety Code § 25249.6, applied to a much broader universe of consumer products than EPA-registered pesticides. The Ninth Circuit has twice held that Prop 65 warning requirements are not preempted as to pesticides under FIFRA when they parallel rather than add to federal labeling.

​

The structural concern is broader. Durnell repackages a register-and-approve regulatory regime as a preemptive ceiling, not a floor. Any agency-approved-label theory of preemption — FDA-approved drug labels, FDA-approved device labels, USDA-approved meat labels, NHTSA-approved vehicle warnings, CPSC-approved appliance warnings — now has a Supreme Court decision standing for the proposition that EPA's silence about cancer is a federal "requirement" of silence about cancer that no state jury may disturb. Plaintiff's counsel will have to draw clear lines between agency regimes that affirmatively review and approve specific warning language and those that operate as registration formalities rather than substantive label review.

​

For Prop 65 enforcers, the lane to defend looks like this: § 25249.6 imposes warning duties triggered by exposure thresholds and listed chemicals, not by labeling determinations made by a federal agency that has affirmatively approved a competing label. Durnell expressly preserved the Bates distinction between state requirements that are "equivalent to" and those that are "in addition to" federal requirements. Prop 65 warnings, framed properly, are not a state-imposed labeling requirement at all — they are a state-imposed disclosure-at-exposure requirement. That distinction needs to be drawn early and drawn hard in any Prop 65 case involving a federally regulated product. But Prop 65 cases almost never concerns such.

The Settlement: $7.25 Billion, Now Worth Considerably More

A week before Durnell came down, Judge Henry Edward Autrey of the Eastern District of Missouri returned the proposed $7.25 billion settlement to Missouri state court after rejecting the objectors' bid to keep it in federal court. (Reuters.) The opt-out deadline ran on June 4. Judge Timothy Boyer in St. Louis is set to consider final approval at the hearing scheduled for early July. With Durnell now on the books — and with Bayer's stock up roughly 16% on the day of the decision — the settlement no longer needs to look like a fair price to plaintiffs uncertain of their odds in state court. It needs only to look like a fair price to plaintiffs whose odds in state court just got materially worse.

​

The Bayer press release was decorous. CEO Bill Anderson called the ruling "overdue justice." The company's outstanding-claims exposure outside the settlement — approximately $1 billion in pending-appeal verdicts, now substantially more vulnerable to Durnell-based vacatur — looks very different than it did Wednesday afternoon.

The Strategic Read

The $1.25 million Durnell verdict was, in retrospect, the single best capital allocation Bayer made all decade. Without that judgment in hand, there is no clean federal vehicle to bring this preemption question up. Bayer paid plaintiff's counsel — through years of litigation costs, jury time, and appellate process — to deliver the Supreme Court a tee shot. The Court hit it 350 yards down the fairway. The check is being couriered now.

​

For anyone litigating against a federally regulated product manufacturer, the playbook just changed.

​

Two practical takeaways:

​

First, identify whether the federal agency has actually approved, with substantive review, the specific warning language at issue — or whether the agency has merely registered, certified, listed, or accepted the product. The depth of agency review is now the entire ball game. Durnell turned on EPA's careful, repeated, multi-cycle review of Roundup's label. A product that has only been notified to the agency, or self-certified, or accepted into a registry, does not carry the same preemptive weight, and the briefs need to make that clear from the first page.

 

Second, for state-law product-liability theories that survive Durnell, lean on the surviving lanes: design defect, post-sale duty to warn (where the relevant federal agency has not made a recent post-sale determination), efficacy-based claims under Bates, and § 136v(a) sale-or-use restrictions for FIFRA matters specifically. Failure-to-warn claims for federally registered pesticides where EPA has refused to require a cancer warning are, as of yesterday, very nearly dead. Plead other things.

 

The Court has spoken. The settlement will close. The plaintiffs' bar will adapt. And somewhere in St. Louis, John Durnell — who never asked for a federal preemption ruling, only a label that mentioned cancer — will spend a Thursday afternoon with the news.