The US Supreme Court ruled 7-2 on Thursday that federal pesticide law bars state-law claims accusing Bayer of failing to warn that its Roundup weedkiller causes cancer, a decision that could cap one of the largest mass-tort liabilities in corporate history.
The court threw out a $1.25 million jury verdict won by a Missouri man who blamed Roundup for his non-Hodgkin lymphoma, ruling that consumers cannot sue over the absence of a cancer warning when federal regulators concluded none was required, Bloomberg reported. The case, Monsanto v. Durnell, turned on whether the Federal Insecticide, Fungicide and Rodenticide Act preempts failure-to-warn claims brought under state tort law.
Justice Brett Kavanaugh, writing for the majority, held that federal law demands uniform pesticide labels and that the state-law claim would have required a cancer warning "in addition to" or "different from" the label approved by the Environmental Protection Agency, according to the opinion. The EPA has consistently found that glyphosate is not likely to cause cancer in humans and has not required Roundup to carry a cancer warning. Justices Neil Gorsuch and Ketanji Brown Jackson dissented, according to Agri-Pulse — a split that did not track the court's usual ideological lines.
The scale of the liability at stake distinguishes the ruling from an ordinary product-liability decision. Bayer has paid more than $10 billion settling Roundup claims since acquiring Monsanto for $63 billion in 2018, and analysts estimate roughly 60,000 to 65,000 claims remain outstanding, according to reporting by Bloomberg. Bayer Chief Executive Officer Bill Anderson has described the litigation as an existential threat to the company and had publicly weighed whether Bayer should continue manufacturing glyphosate at all.
Bayer said the ruling vindicated its central legal argument. "It should help significantly contain the Roundup litigation after nearly a decade of legal battles," the company said in a statement. "The ruling should result in the dismissal of current warning-based claims and bar future failure-to-warn claims." Bayer characterized the decision as good for science, farmers and industries that depend on regulatory clarity.
The market reaction was immediate. Bayer shares rose as much as 17% in Frankfurt, the steepest intraday gain since 2003, before trading was halted for volatility, Reuters and Bloomberg reported.
The decision lands alongside a parallel containment effort. Bayer is pursuing a proposed $7.25 billion class-action settlement covering current and future glyphosate claims, with a final approval hearing scheduled for July 9, according to coverage of the company's litigation strategy. The company has described the settlement and the Supreme Court case as mutually reinforcing steps in its strategy to contain the litigation.
The ruling's reach may extend beyond Bayer. Bloomberg Law noted that the preemption principle could also benefit the medical-device, cosmetic and food industries, which operate under federal labeling regimes structured similarly to FIFRA — meaning the decision could narrow failure-to-warn exposure across multiple regulated product categories where a federal agency has approved labeling.
For insurers and reinsurers carrying product-liability and excess exposure tied to glyphosate, the ruling may reduce a long-running source of uncertainty that had resisted resolution through nearly a decade of inconsistent jury verdicts and appellate splits.
It does not, however, resolve the underlying scientific dispute: the World Health Organization's cancer research arm classifies glyphosate as a probable human carcinogen, the designation that underpinned the litigation in the first place.
The decision is the first time in roughly two decades that the Supreme Court has addressed the scope of FIFRA's preemption power.
