lawsuits

The United States Supreme Court has sided with the maker of Roundup weedkiller in a ruling expected to block thousands of lawsuits alleging it failed to warn people the product could cause cancer.

The ruling on Thursday was tied to a case that came before the justices after a tidal wave of litigation that included some multibillion-dollar verdicts against the global agrochemical manufacturer Bayer, a Germany-based company that acquired Roundup when it bought its original producer Monsanto in 2018.

The decision is a victory for US President Donald Trump’s administration, but one that could be tricky politically since allies in the “Make America Healthy Again” movement want to rein in pesticide use.

The high court, in a 7-2 ruling, found that the company cannot face failure-to-warn lawsuits in state courts because federal regulations have found a cancer link unlikely and do not require a warning label.

The justices overturned a jury verdict in Missouri awarding $1.25m to a man named John Durnell who said he was diagnosed with non-Hodgkin lymphoma after years of exposure to glyphosate in Roundup. The Supreme Court agreed with Bayer that a US law that governs pesticides precludes failure-to-warn claims that are brought under state law from moving forward in court.

Bayer shares jumped nearly 18 percent following the ruling.

Trump’s administration had backed Bayer in the case.

Conservative Justice Brett Kavanaugh, who authored the ruling, said the US Environmental Protection Agency, or EPA, has concluded glyphosate does not cause cancer and has not required a cancer warning on Roundup.

The law preempts Durnell’s claim because it “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”, Kavanaugh wrote.

Liberal Justice Ketanji Brown Jackson, in a dissent joined by conservative Justice Neil Gorsuch, said that Durnell’s claim would impose equivalent labelling requirements on Monsanto that the federal law requires and so should not be preempted.

Jackson called the ruling “remarkable and regrettable, for it unjustifiably closes the courthouse doors to state tort plaintiffs like Durnell”.

Bayer acquired Roundup as part of its $63bn purchase of agrochemical company Monsanto in 2018. More than 100,000 plaintiffs have filed cases in US state and federal courts alleging a cancer link, and the German drugmaking and crop science company had said that the lawsuits could threaten its ability to supply the herbicide to farmers.

The torrent of litigation already prompted Bayer to remove glyphosate from its consumer version of Roundup. Bayer said before the Supreme Court ruled that a decision in its favour could largely end the Roundup litigation.

“The US Supreme Court decision is good for science, farmers, and industries that depend on regulatory clarity for innovation. It should help significantly contain the Roundup litigation after nearly a decade of legal battles. The ruling should result in the dismissal of current warning-based claims and bar future failure-to-warn claims,” Bayer spokesperson Tino Andresen said in a statement.

The company emphasised throughout the litigation that the EPA repeatedly found that glyphosate does not cause cancer and approved its product labels without a warning.

Facing billions of dollars in potential liability, Bayer announced in February a proposed $7.25bn settlement to resolve tens of thousands of current and future lawsuits. The settlement would not affect claims that stem from pending appeals or that fall outside the deal, according to the company. Those amount to nearly $1bn, it said.

‘Disaster for public health’

Environmental activists and others criticised the court’s ruling on Thursday.

“Once again, the Supreme Court has sided with big business over people and the environment. Today’s ruling is a disaster for public health,” said Tarah Heinzen, legal director at the advocacy group Food and Water Watch.

“The harm from this decision will perpetuate our cancer, infertility and general chronic disease epidemic for generations to come,” said Kelly Ryerson, co-executive director of advocacy group American Regeneration and a Make America Healthy Again activist who posts on social media under the moniker “The Glyphosate Girl”.

The sprawling dispute centres on a US law called the Federal Insecticide, Fungicide and Rodenticide Act, or FIFRA, that governs the sale and labelling of pesticides and bars states from imposing differing or additional requirements.

The measure prohibits pesticides that are “misbranded” with labels that lack an adequate warning to protect health and the environment.

Bayer has argued that Durnell’s claims are preempted by this law. The EPA has repeatedly approved labels without such a cancer warning, demonstrating that these products are not misbranded, the company said, adding that labels cannot be substantially changed without the agency’s approval.

Durnell’s lawyers said that despite the EPA’s registration of Roundup, the label may still be challenged as misbranded. They also said Durnell’s claims are not preempted because Missouri state law that requires products to adequately warn of dangers imposes the same requirements as FIFRA’s prohibition on misbranding.

‘A new era’

Union Investment fund manager Markus Manns called Thursday’s ruling a significant milestone for Bayer, adding that a decade after the Monsanto acquisition, the company is “entering a new era”.

“While future lawsuits are not entirely off the table, they will become considerably more difficult. A final breakthrough would come if the settlement is accepted by the plaintiffs and approved by the competent court in July. This would bring Bayer’s glyphosate litigation chapter to a definitive close, allowing management to fully refocus on operational and strategic matters,” Manns said.

Durnell sued Monsanto in Missouri state court in 2019, claiming it failed to warn users of the dangers associated with Roundup and glyphosate.

He was diagnosed with a rare and often aggressive form of non-Hodgkin lymphoma, a cancer that starts in the white blood cells, and attributed the disease to his exposure to Roundup starting in 1996. For about 20 years, he was the “spray guy” for a neighborhood association in St Louis, killing weeds at local parks without protective equipment, according to court papers.

A jury sided with Durnell in 2023, and in 2025, a state appeals court upheld that verdict.

WASHINGTON — The Supreme Court sided with the maker of the Roundup weedkiller Thursday in a ruling expected to block thousands of lawsuits alleging it failed to warn people the product could cause cancer.

The case came before the justices after a tidal wave of litigation that included some multibillion-dollar verdicts against the global agrochemical manufacturer Bayer, which acquired Roundup when it bought its original manufacturer Monsanto in 2018.

The decision is a victory for the Trump administration, but one that could be tricky politically since allies in the Make America Healthy Again movement want to rein in pesticide use.

The high court, in a 7-2 ruling, found that the company can’t be sued in state courts because federal regulations have found a cancer link unlikely and do not require a warning label.

The decision “is good for science, farmers, and industries that depend on regulatory clarity for innovation,” Bayer said in a statement. “It should help significantly contain the Roundup litigation after nearly a decade of legal battles.”

Though Bayer said the ruling should result in the dismissal of pending lawsuits containing failure-to-warn allegations, the company said it plans to proceed with a proposed $7.25 billion class-action settlement intended to resolve many of the remaining claims.

Lawyers for some residents pursuing Roundup litigation criticized the court’s decision.

“This Supreme Court ruling wrongly slams the courthouse door on Americans sickened by pesticides,” said attorney Christopher Seeger, who is proposed as a claimants’ representative in the settlement. But he said a settlement still would allow some people to receive compensation.

The case before the Supreme Court was filed by Missouri resident John Durnell. He developed a cancer called non-Hodgkin’s lymphoma after more than 20 years of serving as the neighborhood association’s “spray guy,” using Roundup on parks in his historic St. Louis community.

A jury agreed that the company failed to warn him about possible cancer dangers and awarded him $1.25 million. It’s one of thousands of similar cases, including some multibillion-dollar damage awards.

There’s still fierce debate about cancer and Roundup’s key ingredient, glyphosate. The World Health Organization’s International Agency for Research on Cancer classified the chemical as “probably carcinogenic” in 2015. The Environmental Protection Agency has determined that it’s not likely to cause cancer in humans when used as directed.

The agency approved a label without a cancer warning, and Bayer argues that it’s required to follow those federal standards — not the state laws that Durnell and others have sued under. The ruling still could allow other suits alleging problems with the way the product was designed, his attorney Ashley Keller has said.

Bayer disputes the cancer claims but previously set aside $16 billion to settle cases, and earlier this year proposed a $7.25 billion class-action settlement. A federal judge recently ruled that the proposed settlement will be heard in a Missouri state court, where many of the lawsuits have been filed. At the same time, the company has tried to persuade states to pass laws shielding it from liability in failure-to-warn lawsuits, and three states have agreed.

About 200,000 Roundup-related claims have been made against Bayer, mostly from home users. It has stopped using glyphosate in Roundup sold in the U.S. residential lawn and garden market.

The company has said it might have to consider pulling glyphosate from U.S. agricultural markets if it keeps getting sued. Agricultural industry group say could have a devastating effect on the food supply.

But pesticides have also created a rift between the Trump administration and members of Health Secretary Robert F. Kennedy’s MAHA movement, adding to their frustration with an executive order aimed at boosting glyphosate’s production.

Kennedy himself has said repeatedly that glyphosate causes cancer, even as he says he recognizes the executive order was necessary for food supply and national security reasons.

Whitehurst writes for the Associated Press. AP writer David A. Lieb in Jefferson City, Mo., contributed to this report.