The Supreme Court ruled in favor of Bayer on Thursday in its fight against lawsuits accusing the company of not warning of the cancer risks of the weedkiller Roundup and its chemical glyphosate.
In a 7-2 decision led by Justice Brett Kavanaugh, the court determined that if the Environmental Protection Agency registers a pesticide and does not require a specific warning on the label, a state cannot impose legal liability on a company for omitting that warning.
The case came to the justices out of Missouri, where plaintiffs tried to force the company to place cancer warnings on its label.
Although state courts were open to the claim, siding with the plaintiff, the majority of the justices were not.
The ruling said the EPA — and federal law — have the final say.
Now, the company cannot be sued over such state-level claims, blocking Roundup customers from using failure-to-warn claims.
Roundup users have argued that the weed-killer’s active ingredient, glyphosate, is carcinogenic, but the EPA has determined that the chemical does not pose a cancer risk if used according to the label’s instructions.
Bayer maintained that Roundup is safe to use, and the EPA has repeatedly determined that it is not likely to be carcinogenic in humans. However, the World Health Organization’s International Agency for Research on Cancer classified glyphosate as “probably carcinogenic to humans” in 2015.
If the court ruled against Bayer, it would be required to add a cancer warning to Roundup’s label even though it uses an EPA-approved label without a cancer warning, Justice Kavanaugh said.
He said that FIFRA “preempts a state-law labeling requirement that differs from the federal labeling requirements imposed under FIFRA. ’Uniformity’ in labeling—the textually stated objective of FIFRA’s preemption clause—would otherwise be impossible to achieve.”
Missouri resident John Durnell, the central figure in the case, won a $1.25 million state court verdict against the company after he developed non-Hodgkin lymphoma in 2023. A Missouri appeals court affirmed the judgment, which the Supreme Court reversed and remanded on Thursday.
Bayer, which acquired Roundup when it bought Monsanto in 2018, said the decision is “good for science, farmers, and industries that depend on regulatory clarity for innovation.”
“It should help significantly contain the Roundup litigation after nearly a decade of legal battle,” it said in a statement. “The ruling should result in the dismissal of current warning-based claims and bar future failure-to-warn claims.”
Justices Ketanji Brown Jackson and Neil Gorsuch dissented from the court’s decision, arguing that the high court “departs from the near unanimous view of the many state and federal courts that have rejected this preemption argument.”
She said that ruling against Durnell leaves him “without a remedy for the significant harms he has suffered.”
Bayer recently entered a $7.25 billion proposed settlement to resolve current and future failure-to-warn lawsuits, except for a few pending court cases.
While this offers the bioagriculture company a huge win in its efforts to resolve costly litigation over Roundup, it came as a blow to the Make America Healthy Again Movement.
Glyphosate has been targeted by MAHA supporters as a harmful chemical. But the movement has felt betrayed by the Trump administration’s embrace of glyphosate after President Trump signed an executive order in February to promote the domestic production of phosphorus and glyphosate.
Health and Human Services Secretary Robert F. Kennedy Jr., a former plaintiffs’ lawyer, won a $289 million verdict against Monsanto in a 2018 failure-to-warn suit. Since then, he has fallen in line with the Trump administration’s embrace of glyphosate.
