The US Supreme Court on Thursday ruled that German agrochemical giant Bayer may not be sued over the absence of cancer warnings on the packaging of its Roundup weedkiller, which contains the chemical glyphosate.
The ruling marks a major victory for Bayer in its long-running legal battle over the weedkiller produced by its subsidiary Monsanto, with tens of thousands of people in the United States having attributed cancer to glyphosate in Roundup.
The top court held that federal law requires standardized labelling approved by the government, preventing individual states from imposing additional warning requirements. The decision is likely to undermine the basis for many current and future lawsuits relating to Roundup.
The ruling stemmed from a case brought by plaintiff John Durnell, whose lawsuit was heard in St Louis in October 2023. A jury found that Bayer should have included a cancer warning on Roundup packaging and awarded Durnell $1.25 million in damages. Bayer subsequently selected the case for appeal in a bid to obtain a precedent-setting ruling from the Supreme Court.
Bayer argued that the US Environmental Protection Agency (EPA) considers glyphosate safe when used according to regulations and had approved the product's label without a cancer warning. The company maintained that damages claims based on individual state laws should therefore not stand.
Glyphosate has been classified by the World Health Organization as "probably carcinogenic to humans." Bayer disputes that finding and continues to deny that Roundup poses a cancer risk.
Following the ruling, Bayer shares surged by as much as 15%. The company welcomed the decision as "good for science, farmers, and industries that depend on regulatory clarity for innovation."
Chief executive Bill Anderson, who took over in June 2023, has pledged to significantly reduce the company's US litigation burden by the end of 2026.
In February, the pharmaceuticals and agrochemicals group announced a $7.25 billion class-action settlement in the United States to resolve Roundup-related claims, although it is still seeking final approval for the agreement.
The Roundup litigation became Bayer's problem in 2018 when it acquired the US seed and chemicals company Monsanto, which manufactures Roundup.
