The U.S. Supreme Court on Jan. 16 said it will hear Bayer’s appeal that asks it to block thousands of lawsuits that allege the company failed to warn consumers that Roundup, its popular weedkiller, could cause cancer.

The new decision in Monsanto Co. v. Durnell took the form of an unsigned order. No justices dissented. The court did not explain the ruling.

In its order, the court said it would consider “whether the Federal Insecticide, Fungicide, and Rodenticide Act preempts a label-based failure-to-warn claim where EPA has not required the warning.”

A state-level jury previously ruled in favor of John Durnell, a Missouri man who developed non-Hodgkin lymphoma after exposure to Roundup, which was developed by Monsanto. The jury found Monsanto liable for failing to warn Durnell of the danger posed by glyphosate and awarded him $1.25 million in damages.

The jury’s finding of liability was upheld by a state appeals court, and the Missouri Supreme Court declined to take up the matter. Many other lawsuits have been filed alleging that Roundup caused medical problems.

Bayer, which purchased Monsanto in 2018, asked the nation’s highest court to overturn the ruling, arguing that federal law governing the labeling of pesticides preempts—or overrides—any state requirements and that the court should take into account how the Environmental Protection Agency has approved labeling Roundup without a cancer warning.

Last month, the Trump administration urged the Supreme Court to intervene in the case.

U.S. Solicitor General D. John Sauer sided with Bayer in a brief, writing that the EPA had found glyphosate, an ingredient in Roundup, “is not likely to be carcinogenic in humans, and the agency has repeatedly approved Roundup labels that did not contain cancer warnings.”

Glyphosate is an herbicide that kills weeds and grasses.

Leaving the Missouri court’s ruling in place means “a jury may second-guess the agency’s science-based judgments,” Sauer said.

The high court needs to protect the labeling authority in the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), he said.

In its petition, Bayer urged the Supreme Court to take up the case, saying that the cost of managing “this veritable flood of litigation has already forced Monsanto to remove glyphosate from the consumer version of Roundup.”

The many lawsuits threaten “Monsanto’s ability to supply the product to farmers who depend on it for their livelihoods … [and undermine] the United States’ position as a world leader in agriculture.”

The petition said the EPA has been registering pesticides that contain glyphosate since 1974. In 2008, the agency reviewed a large database of research and ruled that glyphosate is “not a carcinogen.” Similarly, public health regulators around the world have found that glyphosate does not cause cancer in humans.

The EPA repeatedly affirmed its finding that glyphosate is not carcinogenic since then, but in 2015, a working group of the International Agency for Research on Cancer classified glyphosate as an agent that was “probably carcinogenic to humans,” based on what the petition called “limited evidence.”

The cancer finding of the international agency, which is part of the World Health Organization, was rejected by the European Chemicals Agency, European Food Safety Authority, and the national health authorities of New Zealand, Germany, Canada, and Australia, according to the petition.

The petition said lawsuits challenging the EPA’s ruling on glyphosate were heard by the U.S. Court of Appeals for the Ninth Circuit, and in 2021, the agency again affirmed its determination that glyphosate does not cause cancer in humans. In June 2022, the Ninth Circuit vacated the agency’s non-cancer finding, holding that the EPA failed to provide enough “analysis and explanation.” The EPA reconsidered its finding as the Ninth Circuit ordered, and after doing so again said glyphosate was “not likely to be carcinogenic to humans.” Since then the agency has continued approving labels of various glyphosate-based pesticides without cancer warnings.

After the International Agency for Research on Cancer report came out in 2015, more than 100,000 plaintiffs sued in federal and state courts, claiming Roundup caused their cancers and that Monsanto should have warned them of the risk of using glyphosate-based products. This “tidal wave of litigation forced Monsanto to remove glyphosate from the consumer version of Roundup,” the petition said.

Removing the chemical from consumer-grade Roundup has “sparked fear among American farmers” that Monsanto will also be compelled to remove glyphosate from the agricultural version of the product, a move farmers say would make growing food more difficult and force them to use less desirable pesticides, the petition said.

In a brief urging the Supreme Court not to take up the case, Durnell’s attorneys alleged that Monsanto “has known for decades” that Roundup can cause cancer, but has neither made its product safer, nor told consumers they should be cautious when using it. “Instead, Monsanto has marketed Roundup as safe to spray in a t-shirt and shorts.”

The brief said the company’s argument that FIFRA overrides Missouri’s requirement for a cancer warning “lacks merit,” adding that Monsanto has never proposed such a warning and the EPA has never rejected one. Moreover, the EPA has said the federal statute allows the company to provide the warning, the brief said.

“Missouri has a right to protect its citizens from the detrimental health effects of dangerous pesticides,” and Monsanto has exposed people in the state to “deadly harm.” The company asked the Missouri Legislature to grant it immunity and state lawmakers have declined to do so, the brief said.

“This Court should reject the company’s attempt to get that same relief by judicial fiat,” the brief added.

The oral argument in the case has not yet been scheduled.

Zachary Stieber contributed to this report.

This article by Matthew Vadum appeared Jan. 16, 2026, in The Epoch Times.