The U.S. Supreme Court heard arguments on Monday about whether a St. Louis-based jury was mistaken when awarding damages over how Roundup labels its product.
It's a case that could have broad implications for whether people can sue over pesticides and herbicides.
In 2023, a jury awarded St. Louis resident John Durrell $1.25 million because Roundup didn't have a label warning that the weedkiller carries a cancer risk.
Monsanto representatives have long disputed claims that glyphosate, the active ingredient in Roundup, is linked to cancer. Bayer, which purchased Monsanto in 2018, no longer uses glyphosate in products intended for residential use.
Paul Clement, an attorney for Bayer, said that since the Environmental Protection Agency doesn't require a specific warning about cancer risk, states like Missouri aren't allowed to impose additional labeling requirements.
"The EPA regulation and the government's brief here makes crystal clear that a registrant cannot change the safety warnings on a pesticide label without approval of the agency," Clement said.
Clement was referring to how the Trump administration is siding with Bayer in this case.
"EPA registers pesticides only if EPA approves their labels as adequate to protect health," said Deputy Solicitor General Sarah Harris. "Federal law then requires manufacturers to keep using that label. Manufacturers must apply to amend registration to change the label."
Ashley Keller, an attorney for Durrell, said that in order for Bayer's argument to work, it would require the court to overturn legal precedent showing that products can be labeled wrong – even when the EPA approves the product.
"Monsanto now asks you for the opposite, holding that Roundup cannot be misbranded as a matter of law, because EPA found for the first time, 50 years ago as a matter of fact, that it is safe based on information Monsanto submitted," Keller said.
If Bayer is successful, it could stymie thousands of similar lawsuits across the country based on pesticide and herbicide labeling.
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