The US Supreme Court heard oral arguments on Monday in a case that could determine whether federal law prevents consumers from suing pesticide manufacturers for failing to warn of cancer risks. The case, Monsanto v Durnell, centres on glyphosate, the active ingredient in the weedkiller Roundup, which has been linked to non-Hodgkin lymphoma in multiple studies.
Monsanto, now owned by Germany's Bayer, is asking the court to rule that the Federal Insecticide, Fungicide and Rodenticide Act (Fifra) pre-empts state-level failure-to-warn claims. The company argues that because the Environmental Protection Agency (EPA) has not required a cancer warning on glyphosate labels, it cannot be held liable for not providing one. The EPA maintains that glyphosate is 'unlikely' to be carcinogenic.
Opponents, including plaintiffs' attorney Ashley Keller, argue that Fifra does not provide such blanket pre-emption. Keller noted that the EPA's glyphosate registration review has not been updated every 15 years as required by law, and that the Ninth Circuit Court of Appeals vacated the EPA's human health findings in 2022 for failing to follow proper guidelines.
During arguments, justices questioned both sides on how to handle new scientific evidence that emerges between EPA reviews and whether companies should be retroactively penalised for labels approved by the agency. The court's three liberal justices appeared sceptical of Monsanto's position, while the conservative justices' views were less clear.
Bayer has faced over 100,000 lawsuits related to glyphosate and has paid billions in settlements and jury awards. A ruling in its favour would make it harder for consumers to sue not only Monsanto but other pesticide makers as well. A decision is expected by the end of the court's term in June.
