The US Supreme Court has sharply narrowed the legal exposure of Bayer over its Roundup weedkiller, ruling that a federal pesticide law bars many state-court claims that the company failed to warn users the product could cause cancer.
What the court decided
In Monsanto Co. v. Durnell, the court held 7-2 that the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) preempts state failure-to-warn claims when the Environmental Protection Agency has approved a pesticide's label without requiring a cancer warning, CBS News reported.
Writing for the majority, Justice Brett Kavanaugh reasoned that because the EPA has determined glyphosate is not likely to cause cancer and has never required a warning on Roundup, state tort law cannot impose a separate one; allowing it would conflict with the federal scheme. The dissent came in an unusual pairing — Justice Ketanji Brown Jackson, joined by Justice Neil Gorsuch — arguing the ruling leaves injured users without a remedy.
The case behind it
The suit was brought by John Durnell, a Missouri man who said years of Roundup use caused his non-Hodgkin's lymphoma. A 2023 jury rejected most of his claims but upheld a failure-to-warn count and awarded him $1.25 million; Monsanto appealed, according to Al Jazeera.
Durnell is one of more than 100,000 people in the US who have sued over claims that glyphosate — the active ingredient in Roundup, the world's most widely used herbicide — caused their cancer. The ruling is expected to block the bulk of pending failure-to-warn claims. Other legal theories, such as negligence and design-defect claims, are not covered by the decision and could still proceed.
What it means for Bayer
Bayer, the German company that bought Monsanto in 2018 for roughly $63 billion, welcomed the ruling as a win for regulatory clarity. Its shares rose sharply afterward — by around 18%, according to Al Jazeera, a figure not independently confirmed here. The company has been seeking approval for a settlement of about $7.25 billion to cover future claims; the decision strengthens its position by shrinking the pool of viable lawsuits.
An unresolved scientific dispute
The court did not rule on whether glyphosate actually causes cancer — a question on which expert bodies disagree. The EPA has repeatedly concluded glyphosate is "not likely" to be carcinogenic when used as directed and has not required a warning label, the basis for Bayer's preemption argument. The World Health Organization's International Agency for Research on Cancer, however, classified glyphosate in 2015 as "probably carcinogenic to humans," and some studies have reported associations with non-Hodgkin's lymphoma, though debate over causation continues.
The ruling holds only that, under current federal law, the EPA's labeling determination governs and state courts cannot override it through litigation.
Reaction and reach
Plaintiffs' lawyers and consumer-safety advocates criticized the decision, arguing it shields pesticide makers from accountability so long as they secure favorable EPA labeling, even where other scientific bodies disagree. Analysts noted the precedent could also affect failure-to-warn cases against other pesticide manufacturers. Supporters counter that a single national standard set by the federal regulator is preferable to conflicting requirements imposed state by state. The split dissent — crossing the court's usual ideological lines — underscored that the legal question was genuinely contested.
