The Monsanto failure-to-warn lawsuit that reached the U.S. Supreme Court is Monsanto Company v. Durnell, a Missouri case in which a St. Louis gardener won a $1.25 million verdict after a jury found that Monsanto should have warned Roundup users about a cancer risk. The Court heard argument on April 27, 2026, and a decision is expected by early July 2026 on a single question: whether federal pesticide law preempts state failure-to-warn claims when the EPA never required the warning.1Supreme Court of the United States. Docket, Monsanto Company v. Durnell The answer will shape tens of thousands of pending Roundup claims.
Who John Durnell Is
John Durnell lives in the Soulard neighborhood of St. Louis and belongs to the Soulard Restoration Group. Starting in 1996, he used Monsanto’s glyphosate-based Roundup to maintain a communal garden. Decades later he was diagnosed with non-Hodgkin lymphoma.2Justice Pesticides. John Durnell C Monsanto Co Et Al In January 2019, he sued in the Circuit Court of the City of St. Louis, alleging Monsanto knew glyphosate posed a cancer risk and concealed it.3Chemical & Engineering News. Monsanto Durnell Supreme Court Roundup Glyphosate
Bayer, which bought Monsanto in 2018 for $66 billion, inherited the liability. It has paid more than $11 billion to resolve over 100,000 Roundup claims, with roughly 60,000 still unresolved.4The New Lede. US Judge Calls Proposed Bayer Roundup Settlement a Filthy Deal Durnell’s case is the one the Supreme Court chose to decide the legal question underneath all of them.
The Trial and Verdict
The case went to trial in October 2023 before Judge Timothy Boyer in the Missouri 22nd Judicial Circuit Court.5Penn State Ag Law Center. Judgment Docket, Durnell v. Monsanto Durnell’s attorneys came from OnderLaw of St. Louis, the Frazer Law Firm of Nashville, and Manson, Johnson, Conner PLLC of Nashville. At trial they introduced evidence alleging Roundup’s formulation contained additional carcinogens, including 1,4-dioxane, NNG, arsenic, and formaldehyde.6OnderLaw. OnderLaw Hits Bayer in Its Own Back Yard Using Never Before Seen Evidence
On October 20, 2023, the jury returned $1.25 million in compensatory damages on the strict-liability failure-to-warn claim. It sided with the 2015 finding by the International Agency for Research on Cancer that glyphosate is “probably carcinogenic to humans” and found a causal link between Durnell’s Roundup exposure and his cancer.2Justice Pesticides. John Durnell C Monsanto Co Et Al7IARC / WHO. Glyphosate Monograph Now Available The jury rejected Durnell’s defective-design and negligence claims, finding Monsanto liable only on failure to warn.8FindLaw. Durnell v. Monsanto, Missouri Court of Appeals Nine of twelve jurors signed the verdict; the three holdouts thought damages were too low, not too high.6OnderLaw. OnderLaw Hits Bayer in Its Own Back Yard Using Never Before Seen Evidence It was the first Roundup trial loss for Bayer outside California and the first in Monsanto’s hometown.
Monsanto appealed. On February 11, 2025, the Missouri Court of Appeals, Eastern District, affirmed. The court held that Monsanto had not shown an “irreconcilable conflict” between state and federal law: prior EPA approval of a label without a cancer warning did not prove the agency would reject one added later.9Cornell Law Institute. Monsanto Co. v. Durnell, Certiorari
The Preemption Question at the Supreme Court
The Supreme Court granted certiorari on January 16, 2026, limited to a single question: “Whether the Federal Insecticide, Fungicide, and Rodenticide Act preempts a label-based failure-to-warn claim where EPA has not required the warning.”1Supreme Court of the United States. Docket, Monsanto Company v. Durnell
FIFRA’s “uniformity” provision bars states from imposing labeling requirements “in addition to or different from” federal ones.10National Agricultural Law Center. Third Circuit Rules Failure to Warn Claims Preempted by FIFRA The Court’s 2005 decision in Bates v. Dow Agrosciences held that state-law claims running parallel to FIFRA’s own misbranding prohibitions survive preemption, but left ambiguous how to define the federal “requirement” a state claim is measured against.11FindLaw. Bates v. Dow Agrosciences LLC
Federal appellate courts have split on how to read that gap. The Ninth Circuit in Hardeman v. Monsanto (2021) and the Eleventh Circuit in Carson v. Monsanto (2024) held that state failure-to-warn claims are not preempted. Both concluded that EPA registration of a specific label is not itself a preemptive federal command; the Eleventh Circuit called it only “prima facie evidence” of compliance.12U.S. Court of Appeals for the Ninth Circuit. Hardeman v. Monsanto Co.13U.S. Court of Appeals for the Eleventh Circuit. Carson v. Monsanto Co. The Third Circuit went the other way in Schaffner v. Monsanto (August 2024), holding that because federal regulations bar a manufacturer from altering an approved label without EPA permission, a state-law duty to add a cancer warning imposes a requirement “different from” federal law.14U.S. Court of Appeals for the Third Circuit. Schaffner v. Monsanto Corp.
The Arguments
Former Solicitor General Paul Clement argued for Monsanto. He advanced both express preemption, citing FIFRA’s “in addition to or different from” language, and implied preemption, arguing that a manufacturer cannot simultaneously obey an EPA-approved label and a state jury’s demand for a cancer warning it lacks. Clement analogized to Riegel v. Medtronic, where the Court held that agency-imposed medical device requirements preempt conflicting state tort claims.15SCOTUSblog. Justices Debate Who Gets to Decide That Pesticide Labels Need a Cancer Warning16Legal Planet. Roundup at the Supreme Court
The federal government filed as amicus supporting Monsanto, reversing its earlier position in Hardeman. Principal Deputy Solicitor General Sarah Harris argued that EPA registration is a product-specific federal requirement, that manufacturers cannot add precautionary language without approval, and that state tort juries do not conduct the cost-benefit analysis FIFRA assigns to the EPA.17Supreme Court of the United States. Brief for the United States as Amicus Curiae, Monsanto Co. v. Durnell
Ashley Keller of Keller Postman argued for Durnell. He countered that a registered herbicide can still be “misbranded” under FIFRA when new safety data emerges, and said Monsanto was asking the Court to hold that Roundup could never be misbranded as a matter of law because the EPA found it safe fifty years ago based on information Monsanto itself submitted.18Courthouse News Service. Supreme Court Looks to Shut Down $1.25M Labeling Suit Against Roundup
Oral Argument
The justices heard roughly 75 minutes on April 27, 2026, and their questions did not track ideological lines. Justice Ketanji Brown Jackson asked why states cannot update labeling during the 15-year gap between EPA registrations when new science emerges. Chief Justice John Roberts suggested states might respond faster than the EPA and questioned barring them from alerting the public during federal review. Justice Neil Gorsuch pressed Monsanto on an apparent inconsistency: if a state can ban a pesticide outright, why can it not require a label change?3Chemical & Engineering News. Monsanto Durnell Supreme Court Roundup Glyphosate
On the other side, Justices Elena Kagan and Samuel Alito pushed on how state-by-state litigation squares with FIFRA’s uniformity goal and raised the Court’s 2024 Loper Bright v. Raimondo decision, which ended judicial deference to agency statutory interpretations. Justice Brett Kavanaugh asked how a uniform label survives if every state can impose different requirements. Keller drew notably fewer questions than the other advocates, which observers said made it hard to read the Court’s leanings.15SCOTUSblog. Justices Debate Who Gets to Decide That Pesticide Labels Need a Cancer Warning
What a Ruling Would Mean
If the Court sides with Monsanto, FIFRA would preempt failure-to-warn claims nationwide when the EPA has approved the label without the warning at issue. That would remove the legal theory underneath most of the tens of thousands of pending Roundup cases. If the Court affirms the Missouri courts, plaintiffs will retain the ability to argue that state juries can hold pesticide makers liable for warnings the EPA never required. A decision is expected by early July 2026.19SCOTUSblog. Monsanto Company v. Durnell
The $7.25 Billion Proposed Class Settlement
While the Supreme Court case was pending, Bayer in February 2026 announced a proposed $7.25 billion class settlement in the St. Louis Circuit Court to resolve nearly all remaining Roundup claims. It covers people who allege Roundup exposure before February 17, 2026, and who have or will develop non-Hodgkin lymphoma within a 16-year window. Payments are tiered, averaging roughly $10,000 to $165,000, with occupational users receiving more than residential users.20The New Lede. Not So Fast: Lawyers for Cancer Victims See Red Flags in Bayers Roundup Judge Timothy Boyer, who presided over the Durnell trial, granted preliminary approval in March 2026.21Reuters. Federal Judge Sends Bayers $7.25 Billion Roundup Settlement Back to Missouri State
The deal is contested. U.S. District Judge Vince Chhabria, who has overseen nationwide Roundup litigation since 2016, called it a “filthy deal” and “legally problematic,” though he lacks jurisdiction over the Missouri state proceedings.22Investigate Midwest. Bayers Proposed Roundup Settlement Violates Constitution, New Legal Filing Claims In May 2026, plaintiffs’ attorneys including Keller and the Frazer firm filed objections arguing the settlement is unconstitutional, violates due process, sweeps in a “futures” subclass of people who have not yet developed cancer (including children), and uses the pending Supreme Court ruling to pressure plaintiffs into accepting the deal before the Court acts. A final approval hearing is set for July 2026.
A Note on Residential Roundup
Bayer announced in 2021 that it would remove glyphosate from Roundup sold for residential lawn and garden use in the United States, a transition that began in late 2022. The new formulations use fluazifop-p-butyl, triclopyr, diquat dibromide, and imazapic. Bayer said the change was made “exclusively to help manage litigation risk and not because of any safety concerns with glyphosate.”23Bayer. Roundup Ingredient Safety Glyphosate-based Roundup remains on the market for agricultural and professional use, and the reformulation does not affect pending or past claims.