The United States Supreme Court has ruled in favor of Bayer in a decision expected to significantly reduce thousands of lawsuits alleging the company failed to warn users that its Roundup weedkiller could cause cancer.
The court voted 7-2 to overturn a Missouri jury verdict that awarded $1.25 million to John Durnell, who claimed he developed non-Hodgkin lymphoma after years of exposure to glyphosate, the active ingredient in Roundup.
The ruling determined that federal pesticide law preempts state failure-to-warn claims because the Environmental Protection Agency has approved Roundup's labeling without requiring a cancer warning.
The decision marks a major legal victory for Bayer, which acquired Monsanto and the Roundup brand through its $63 billion acquisition in 2018.
Writing for the majority, Justice Brett Kavanaugh said federal law requires Monsanto to use the EPA-approved label without a cancer warning, preventing states from imposing additional labeling requirements through lawsuits.
The court found that the Federal Insecticide, Fungicide and Rodenticide Act bars state claims that would effectively require labels differing from those approved by the EPA.
Justice Ketanji Brown Jackson dissented, joined by Justice Neil Gorsuch, arguing that the Missouri claim imposed equivalent labeling obligations rather than conflicting ones.
The decision reverses Durnell's 2023 jury victory, which had been upheld by a Missouri appeals court earlier this year.
More than 100,000 plaintiffs have filed lawsuits in U.S. state and federal courts alleging a connection between Roundup and cancer.
Bayer has consistently argued that the EPA has repeatedly concluded glyphosate does not cause cancer and has approved the product's labeling without warning language.
Following the ruling, Bayer shares rose sharply as investors viewed the decision as significantly reducing the company's legal exposure.
The company previously announced a proposed $7.25 billion settlement covering tens of thousands of current and future lawsuits, although certain pending appeals and other claims remain outside that agreement.
Environmental advocacy groups criticized the decision, while Bayer said the ruling should substantially limit warning-based litigation and provide greater regulatory certainty going forward.