An anonymous reader quotes a report from NPR: A divided U.S. Supreme Court on Monday heard a dispute over labels on the popular Roundup weed killer, which thousands of people blame for their cancers. How the Supreme Court rules could have implications for tens of thousands of lawsuits against Roundup maker Monsanto, which is now owned by Bayer. The case centers on who decides about warning labels on chemicals: the federal government -- or states or juries. [...] The justices will not be evaluating whether glyphosate causes cancer. Rather, they'll consider who should decide what appears on warning labels and whether states have a role to play after the EPA weighs in. The current U.S. solicitor general backed Monsanto. Sarah Harris, his principal deputy, said the Environmental Protection Agency is in the driver's seat, not anyone in Missouri. "Missouri thus requires adding cancer warnings but federal law requires EPA to approve new warnings and tasks EPA with deciding what label changes would mitigate any health risks," Harris argued. "State law must give way." Several justices, including Brett Kavanaugh, appeared to agree with Monsanto's argument about the need for a single, uniform standard across the country. But others, like Chief Justice John Roberts, wondered what would happen if the federal government moved more slowly than states did, who wanted to act quickly on information about new dangers. "Well, it does undermine the uniformity," Roberts said. "On the other hand, if it turns out they were right, it might have been good if they had an opportunity to do something, to call this danger to the attention of people while the federal government was going through its process," he said about states. Justice Ketanji Brown Jackson asked about the emergence of new science, and the EPA's reviews. "There's a 15-year window between when that product has to be re-registered again and lots of things can happen in science, in terms of development about the product," she said. Bayer, which now owns Monsanto, only sells Roundup that contains glyphosate to farmers and businesses these days. Bayer has been pushing to resolve scores of the residential cases through a sweeping settlement, trying to put the costly claims behind it.Read more of this story at Slashdot.