US Supreme Court scales back Roundup cancer lawsuits

The U.S. Supreme Court has reined in thousands of lawsuits filed in state courts accusing Bayer of failing to warn users that the active ingredient in its Roundup weed killer caused cancer, handing the German company a major legal victory.

In a 7-2 decision, the justices overturned a jury verdict that awarded US$1.25 million ($A1.81 million) in damages to a Missouri man named ‌John Durnell, who said he was diagnosed with non-Hodgkin’s lymphoma after years of exposure to glyphosate in Roundup.

The Supreme Court agreed with Bayer that U.S. law regulating pesticides prevented failure-to-warn claims brought under state law from advancing in court.

Bayer acquired Roundup as part of its $63 billion acquisition of agricultural chemicals company Monsanto in 2018.

More than 100,000 plaintiffs have filed suit in US state and federal courts alleging a link to cancer, and the German pharmaceutical manufacturing and plant science company said the lawsuits could threaten its ability to supply herbicides to farmers.

Numerous lawsuits led Bayer to remove glyphosate from the consumer version of Roundup.

Bayer said before the Supreme Court ruled that a ruling in its favor could largely end the Roundup lawsuit.

The Supreme Court heard arguments in the case in April.

“The U.S. Supreme Court’s decision is good for science, farmers, and industries that need regulatory clarity for innovation. It should help bring significant control to the Roundup litigation after nearly a decade of legal battles. The decision should result in the dismissal of current warning-based claims and bar future failure-to-warning claims,” ​​company spokesman Tino Andresen said in a statement.

The company has emphasized throughout the lawsuit that the U.S. Environmental Protection Agency has repeatedly found that glyphosate does not cause cancer and has approved product labels without warning.

Facing billions of dollars in potential liability, Bayer announced in February that it was offering a $7.25 billion settlement to resolve tens of thousands of current and future lawsuits.

According to the company, the settlement will not affect claims arising from pending appeals or that fall outside the settlement.

It was stated that this amount was approximately 1 billion US dollars.

Environmental activists and others criticized the court’s decision on Thursday.

“The Supreme Court has once again sided with big business on people and the environment. Today’s decision is a disaster for public health,” said Tarah Heinzen, legal director of the advocacy group Food and Water Watch.

“The damage this decision will do will perpetuate our epidemic of cancer, infertility, and overall chronic disease for generations to come,” said Kelly ‌Ryerson, co-executive director of American Regeneration and a Make America Healthy Again activist who posts on social media as “Glyphosate Girl.”

The widening dispute centers on a U.S. law called the Federal Insecticide, Fungicide and Rodenticide Act, or FIFRA, that regulates the sale and labeling of pesticides and prevents states from imposing different or additional requirements.

The measure bans pesticides that are “misbranded” with labels that do not include adequate warnings to protect health and the environment.

Bayer argued that Durnell’s claims were preempted by this law.

The EPA has repeatedly approved labels without such a cancer warning, showing that these products are not misbranded, the company said, adding that the labels cannot be substantially changed without the agency’s approval.

Even though the EPA registered Roundup, the label could still be challenged on the grounds that it is misbranded, Durnell’s lawyers said.

They also said Durnell’s claims were not preempted because the Missouri state law requiring products to be adequately warned of dangers imposes the same requirements that FIFRA prohibits misbranding.

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

He was diagnosed with a rare and often aggressive form of non-Hodgkin lymphoma, a type of cancer that begins in white blood cells, and was attributed to exposure to Roundup starting in 1996.

For nearly 20 years, he worked as a “sprayer” for a neighborhood association in St. Louis, killing weeds in local parks without protective equipment, according to court documents.

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