Supreme Court overturns $1.25 million Roundup lawsuit

Though the court's decision focused narrowly on labelling requirements and not the question of whether Roundup ingredients cause cancer, it could have significant implications for thousands of lawsuits brought against Monsanto by Americans who claim they were sickened by Roundup.

The Bayer corporation, which now owns Monsanto, has set aside $16 billion to settle a tsunami of lawsuits over the weedkiller.

In 2025, a Missouri jury decided that Monsanto, which is now owned by the German pharmaceutical and life sciences giant Bayer, failed to warn St. Louis native John Durnell about the possible carcinogenic properties of their product, Roundup, as required by Missouri law. Durnell claims that he developed non-Hodgkins lymphoma as a result of using Roundup, which contains the controversial chemical glyphosate.

The Missouri jury awarded Durnell $1.25 million in damages.

The Missouri Court of Appeals upheld the jury award, which prompted Monsanto to appeal to the Supreme Court.

Monsanto argued that it was not required to label the product because such labeling was not required by the federal EPA. 

The court's majority, an unusual combination of liberal and conservative justices, found in favor of Monsanto's contention that EPA’s past approval of glyphosate preempts Missouri’s failure-to-warn laws.

Justices Ketanji Brown Jackson and Neil Gorsuch joined in a dissent.

Since 1947, the Federal Insecticide, Fungicide, and Rodenticide Act, has acted as the federal statute that governs the labeling and sale of pesticides in the US.

In 2015, the International Agency for Research on Cancer, a part of the World Health Organization, broke from years of glyphosate-related decisions and classified the chemical as “probably carcinogenic to humans.” In response, the EPA claimed that it “considered a significantly more extensive and relevant dataset” than the IARC, and does not agree with the agency’s conclusion.

This classification launched over 100,000 cases against chemical manufacturers, with many centering around Monsanto.

In briefs submitted to the court before oral arguments, both sides claimed that FIFRA actually proves their case.

Monsanto points to a part of the act that states, “EPA prohibits the sale and distribution of unregistered, adulterated, or misbranded pesticides and the use of any registered pesticide in a manner inconsistent with its labeling.”

“(Durnell’s) label-based failure-to-warn claim is preempted twice over,” said Paul Clement, the lawyer representing Monsanto, during oral arguments before the Supreme Court.

“Here, a Missouri jury imposed a cancer warning requirement that the EPA does not require,” Clement said. “That additional requirement is preempted.”

The company states that because the EPA has always approved their labels and the use of glyphosate in their products, that FIFRA preempts Missouri’s state failure-to-warn laws. They point to FIFRA’s strict uniformity clauses, and claim that if every state has their own say, it would create an unnecessary burden on the company to create 50 different labels for the same product.

They also use this provision of FIFRA to affirm that they would not have been able to add an unsanctioned cancer warning to their product. In the Missouri trial, Durnell’s lawyers stated that there was no evidence that Monsanto had ever submitted a possible cancer warning to the EPA.

Durnell's lawyers pointed to another part of the act that states, “Under FIFRA, States have broad authority to regulate pesticides…”

“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,” said Ashley Keller, the lawyer representing Durnell, during oral arguments.

“State law must give way,” Keller added.

This specific quote from the act does go on to say, “...however, it is unlawful for States to impose or continue in effect any requirements for labeling or packaging in addition to or different from those required under FIFRA.”