WASHINGTON - The Supreme Court on Monday barred thousands of lawsuits alleging Bayer’s Roundup weedkiller causes cancer, ruling that federal pesticide regulations preempt state warning requirements.
The 7-2 decision held that because the Environmental Protection Agency has not determined glyphosate, Roundup’s active ingredient, poses a cancer risk, plaintiffs cannot claim the product’s label violates state hazardous-product laws. The ruling effectively shields Bayer from billions in potential damages.
Bayer inherited the litigation when it acquired Monsanto in 2018. While it has removed glyphosate from residential Roundup products, the company warned that continued litigation could force it to stop selling glyphosate to U.S. farmers, endangering food supply chains.
Lawsuits multiplied after a World Health Organization agency in 2015 classified glyphosate as “probably carcinogenic.” One plaintiff, John Durnell, used Roundup for over two decades and won a $1.25 million verdict in 2023 after developing non-Hodgkin lymphoma. The Supreme Court’s ruling, however, rejects a role for state law when EPA does not mandate cancer warnings.
Bayer is also pursuing a class-action settlement and legislative protections to limit future liability. The EPA’s own safety review is years overdue after a federal court faulted its initial assessment under the first Trump administration.