Supreme Court to Weigh Whether Federal Law Blocks Roundup Cancer Lawsuits

The U.S. Supreme Court said it will take up a closely watched case that could determine whether tens of thousands of people who claim the weedkiller Roundup caused their cancer will be allowed to pursue their lawsuits in court, or whether federal pesticide law will effectively shut those cases down. 

The justices’ decision to hear the case carries major consequences for both agriculture, which relies heavily on Roundup, and for consumers who allege that Monsanto failed to adequately warn about the product’s cancer risks. The ruling could also resolve a long-running legal question about whether federal pesticide regulations override state-law claims brought by injured users. 

The court is expected to hear oral arguments in the spring. 

Monsanto, the maker of Roundup, was acquired by German pharmaceutical and chemical giant Bayer in 2018. Since then, Bayer has been grappling with massive litigation tied to the herbicide, which contains the active ingredient glyphosate. 

The appeal before the Supreme Court stems from a $1.25 million jury verdict awarded to John Durnell, a Missouri man who sued Monsanto in state court in 2019. Durnell alleged that long-term exposure to Roundup caused him to develop non-Hodgkin’s lymphoma. A Missouri appellate court later upheld the jury’s verdict, clearing the way for Monsanto to seek Supreme Court review. 

Monsanto has faced more than 100,000 similar claims nationwide from plaintiffs who say they were diagnosed with cancer after using Roundup. The company argues that a federal law passed in the 1970s, which grants the Environmental Protection Agency authority to regulate pesticide labeling, preempts state-law failure-to-warn claims like Durnell’s. If the Supreme Court agrees, many of the pending lawsuits against the company could be dismissed or blocked from moving forward. 

The case also presents a political wrinkle for the Trump administration, which has supported Monsanto’s legal position despite the long-standing criticism of Roundup by Health and Human Services Secretary Robert F. Kennedy Jr., who has repeatedly questioned the safety of glyphosate. 

While Monsanto has removed glyphosate from consumer versions of Roundup sold for home use, the chemical remains the key ingredient in industrial and agricultural formulations that are widely used by farmers across the country. 

The scientific debate over glyphosate has been central to the litigation. The EPA, under both Democratic and Republican administrations, has repeatedly concluded that glyphosate does not cause cancer and has declined to require cancer warnings on Roundup’s label. Monsanto has pointed to those findings as evidence that it complied with federal law. 

The controversy intensified further while the Supreme Court case was pending, when a scientific journal retracted a landmark study published 25 years ago that had concluded glyphosate was safe. Emails uncovered in separate litigation revealed that Monsanto employees were heavily involved in the research. The journal said that involvement raised “serious ethical concerns regarding the independence and accountability” of the study’s authors. 

In its Supreme Court filing in April, Monsanto emphasized the EPA’s long-standing position on glyphosate. “EPA has repeatedly determined that glyphosate, the world’s most widely used herbicide, does not cause cancer,” the company’s attorney wrote. “EPA has consistently reached that conclusion after studying the extensive body of science on glyphosate for over five decades.” 

Bayer welcomed the Supreme Court’s decision to hear the case. In a statement released Friday, the company said the move represents “an important step in our multi-pronged strategy to significantly contain this litigation.” 

The eventual ruling could reshape the future of Roundup litigation nationwide and clarify how far federal regulatory authority extends in shielding companies from state-law claims involving alleged health risks.