Supreme Court Bars Roundup Cancer Lawsuits

On June 25, 2026, the U.S. Supreme Court ruled 7-2 that existing federal law prevents failure-to-warn injury lawsuits in state courts against Monsanto Company by individuals whose health deteriorated from exposure to the company’s glyphosate-containing Roundup weed killer. The decision in Monsanto Co. v. Durnell reversed a Missouri jury verdict awarding plaintiff John Durnell $1.25 million after he developed non-Hodgkin’s lymphoma following approximately 20 years of Roundup use.¹

In 2019, Durnell sued the Bayer owned company in Missouri state court alleging that the glyphosate-based formula of Monsanto’s Roundup weed killer caused cancer and the company failed to include a cancer warning on its Roundup label.  The jury found for Durnell on the failure-to-warn theory and awarded him $1.25 million. The Missouri Court of Appeals affirmed the verdict. Because, multiple federal courts of appeals and state courts had reached conflicting conclusions on whether federal law preempts such state claims, the U.S. Supreme Court granted the matter certiorari.²

Federal Law Governs Pesticide Labels

The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), enacted in 1947 and substantially revised in 1972, placed the Environmental Protection Agency (EPA) in charge of pesticide registration and labeling. Under FIFRA, manufacturers are required to submit proposed labels to the EPA before selling a pesticide product. The EPA is required to ensure that the product label is not false or misleading and that it contains all warnings “necessary and adequate to protect health and the environment.”

Once the EPA approves a label, the pesticide manufacturer is legally required to use that label and cannot change it without EPA approval. FIFRA’s preemption clause, titled “Uniformity,” 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.” 7 U.S.C. §136v(b).³

The EPA Has Never Required a Cancer Warning

The EPA first registered glyphosate-based pesticides including Roundup in 1974 and approved Roundup’s label without a cancer warning. In 1991, the EPA formally classified glyphosate as “unlikely” to cause cancer in humans. In 2015, the International Agency for Research on Cancer (IARC) classified glyphosate as a probable carcinogen.

The EPA re-examined glyphosate in 2017 and again in 2019, maintaining the position that glyphosate is not likely to cause cancer in humans. Regulatory agencies in Canada, Australia, Japan, and the European Union have reached the same conclusion. Because the EPA has not required a cancer warning, federal law does not require that Monsanto add a cancer warning to product labels on Roundup.⁴

Verdicts Against Monsanto

Before the Supreme Court reversed Durnell’s verdict, juries across the country had been finding against Monsanto in Roundup-linked cancer cases for years. In August 2018, Dewayne Johnson, a school groundskeeper with terminal non-Hodgkin’s lymphoma, won a $289 million verdict against Monsanto in San Francisco Superior Court after years of applying Roundup. The jury found Monsanto had acted with malice and failed to warn users of the cancer risk from exposure to glyphosate. A California appeals court later reduced the award to $20.5 million but affirmed the failure-to-warn finding.⁵

In February 2019, Edwin Hardeman, who had used Roundup on his residential property for more than 25 years before developing non-Hodgkin’s lymphoma, won a federal jury verdict of more than $80 million against Monsanto. The Ninth Circuit Court of Appeals affirmed the causation finding and the failure-to-warn claim.⁶

In May 2019, a California jury awarded Alva and Alberta Pilliod $2.055 billion after both developed non-Hodgkin’s lymphoma following decades of Roundup use on their property. A California appeals court reduced the award to $87 million. In June 2022, the U.S. Supreme Court declined to hear Monsanto’s appeal.⁷

The verdicts followed evolving scientific literature. In 2015, the IARC classified glyphosate as a Group 2A probable carcinogen based on evidence of cancer in humans, sufficient evidence in animals, and mechanistic evidence of genotoxicity and oxidative stress in human cells.⁸ In 2019, researchers at the University of California Berkeley, the University of Washington, and the Icahn School of Medicine at Mount Sinai published a meta-analysis in Mutation Research of six studies with nearly 65,000 participants. They found that people with the highest cumulative exposure to glyphosate-based herbicides had a 41 percent increased risk of non-Hodgkin’s lymphoma.⁹

A 2024 study showed that the link between agriculture pesticide use and cancer was as strong as the link between smoking cigarettes and cancer. The study showed a strong link between the use of the pesticides and leukemia, non-Hodgkin’s lymphoma, bladder, colon, lung, and pancreatic cancers, as well as other cancer combinations.¹⁰

Supreme Court Finds Federal Law Preempts State Law

Justice Brett Kavanaugh wrote the majority opinion, joined by Chief Justice John Roberts and Justices Clarence Thomas, Samuel Alito, Sonia Sotomayor, Elena Kagan, and Amy Coney Barrett. The majority held that Durnell’s state tort claim would impose a labeling requirement “in addition to or different from” what federal law requires and is therefore expressly preempted under FIFRA. The Court wrote:

But Durnell’s state tort claim would require Monsanto to add a cancer warning to Roundup’s label even though federal law requires Monsanto to use the EPA-approved label without a cancer warning. Because Durnell’s state tort claim would impose a pesticide labeling requirement ‘in addition to or different from’ the label required by EPA, FIFRA expressly preempts Durnell’s claim.¹¹

The Dissent Finds No Preemption

Justices Ketanji Brown Jackson and Neil Gorsuch dissented. Justice Jackson argued that Missouri’s failure-to-warn claim simply parallels FIFRA’s own misbranding prohibition, which also requires manufacturers to include adequate and necessary warnings. Because the two standards impose equivalent duties, she concluded that Durnell’s claim is not “in addition to or different from” federal requirements and is not preempted. Justice Jackson wrote:

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. This interpretation cannot be squared with the text of FIFRA or our precedents. Ultimately, the effect of the majority’s interpretation is both remarkable and regrettable, for it unjustifiably closes the courthouse doors to state tort plaintiffs like Durnell.¹²

Bayer Off the Hook

Bayer AG acquired Monsanto for approximately $66 billion in 2018, assuming responsibility for more than 60,000 Roundup lawsuits as part of the deal. At the time of the ruling, Bayer had a $7.25 billion class settlement pending. On the day the Court issued its decision, Bayer’s stock climbed 19 percent, its largest single-day gain in 23 years.¹³ Approximately 200,000 Roundup claims were pending when the ruling was issued.¹⁴

Bayer Chief Executive Officer Bill Anderson issued a statement following the ruling, saying:

This litigation has enormous costs for the company and has impacted public trust. The decision brings overdue justice on an issue that should have been clarified much earlier. It’s time to put it behind us.¹⁵

Christopher Seeger, proposed class counsel in the Roundup settlement, said in a statement:

This Supreme Court ruling wrongly slams the courthouse door on Americans sickened by pesticides, and underscores why we negotiated a $7.25 billion settlement that guarantees compensation to Roundup victims regardless of today’s decision. We urge those opposing this agreement … to drop their opposition so that tens of thousands of cancer victims no longer have to wait for justice after a decade of delay.¹⁶

New Pesticides Approved Since the Ruling

In the days since the Supreme Court’s decision, EPA approved six pesticides or expanded existing approvals. They include fluoxapiprolin, epyrifenacil, diflufenican, trifludimoxazin, an expanded approval for chlormequat chloride, and an expanded approval for bifenthrin.
Chlormequat chloride, which has been shown in animal studies to disrupt fetal growth and damage the reproductive system, has been detected in 90 percent of Americans tested.

Chlormequat chloride, which has been shown in animal studies to disrupt fetal growth and damage the reproductive system, has been detected in 90 percent of Americans tested.^{17 18}

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