US supreme court weighs blocking lawsuits against Roundup makers alleging weedkiller causes cancer | US supreme court
U.S. Supreme Court members peppered lawyers for the former Monsanto Corp. with questions Monday over pesticide regulation and wrestled with whether federal law preempts state actions that allow consumers to sue companies for failing to warn about product risks such as cancer.
The Monsanto v Durnell case focuses on glyphosate, a weed-killing chemical used in the popular brand Roundup, and numerous other herbicide products sold by the former Monsanto company, now owned by Germany’s Bayer.
It became chemical scientifically linked It has caused cancer in many studies and was classified as a probable human carcinogen by an arm of the World Health Organization in 2015.
Bayer has spent the last decade fighting more than 100,000 lawsuits filed by people who developed non-Hodgkin’s lymphoma, which they blamed on exposure to Monsanto’s glyphosate weed killers. The company has paid billions of dollars in jury awards and settlements.
In the Durnell case and many other cases that went to trial, juries found that Monsanto failed to warn the plaintiff that glyphosate could cause cancer.
While Monsanto claims its products do not cause cancer, it is asking the high court to rule that it cannot be held liable under the Federal Insecticide, Fungicide, and Rodenticide Act (Fifra) for failing to warn about a cancer risk if the Environmental Protection Agency (EPA) did not find that such a risk existed and did not require such a warning. EPA’s opinion that glyphosate “unlikely” is to be carcinogenic.
If Monsanto prevails before the high court, it will become harder for consumers to file such lawsuits not only against Monsanto but also against other pesticide manufacturers.
Paul Clement, an attorney representing Monsanto, told the justices in argument before the court that Fifra provisions, which prohibit pesticide manufacturers from changing pesticide label safety warnings without EPA approval, are “clear” and therefore cannot be held liable for failing to provide cancer warnings.
“Congress clearly wanted uniformity regarding pesticide label safety warnings,” Clement told the justices. “Ignoring Congress’s clear guidance here would cripple accountability and undermine the interests of farmers who depend on federally registered pesticides for their livelihoods.”
Clement has repeatedly argued that the EPA’s process for approving a pesticide is stringent and that its stance that glyphosate is not carcinogenic is supported by other regulatory agencies “around the world.”
Justice Department deputy attorney general Sarah Harris also argued in favor of Monsanto’s position. Harris told the justices that states cannot try to “second-guess or undermine” the EPA process.
Ashley Keller, an attorney against Monsanto, told the justices that “the United States was wrong” and said Fifra did not provide the blanket authority Monsanto requested with “preemptive power.” He also told the justices that the EPA’s registration process had significant flaws and did not update its glyphosate registration review every 15 years as required by law. “Things are getting out of hand with that agency,” he said.
He also said the EPA’s findings regarding human health and glyphosate were: vacated by ninth circuit court of appeals for not following established guidelines for determining cancer risk in 2022 and ignoring important studies.
Sometimes interrupted mid-argument, the judges questioned the lawyers on many aspects. Some pressed Monsanto’s attorney on how labeling issues should be handled when new science showing harm emerges amid EPA reviews, while others asked whether it was fair to retroactively penalize a company for the lack of a warning on an EPA-approved label.
The court’s three liberal justices were skeptical of Monsanto’s claim, but it was less clear how the other justices might rule.
“Both sides presented a good case,” said Daniel Hinkle, senior policy counsel for the American League for Justice, who attended oral arguments. “I thought they were asking some serious questions and really grappling with the implications of the case.”
Bayer said the high court’s positive decision would help bring the case to an end. Bayer issued a statement following the high court hearing expressing appreciation for “the court’s careful consideration of Fifra’s uniformity language and how the federal preemption provision applies to state-based label warnings.”
“We believe that the U.S. government and the company have presented persuasive arguments that state-based warning claims ‘in addition to or distinct from’ EPA-approved warning labels under FIFRA, as in Durnell, are preempted and that this is necessary to avoid a patchwork of 50 different warning labels,” the company said. “Companies should not be penalized under state law for complying with federal labeling requirements. The safety and affordability of the nation’s food supply depends on the ability of farmers and producers to trust the science-based decisions of federal regulators.”
Before and during the hearing, protesters affiliated with the Maha movement gathered outside the court to protest the Trump administration’s support for Monsanto; They cited the attorney general’s support for Monsanto’s position, as well as Trump’s recent executive order declaring the protection of glyphosate production a national security issue. Some shouted “people have been poisoned” and others waved signs with slogans such as “Round up the criminals” and “Make Monsanto pay for this.”
“It’s so important to come out right now and let not only the supreme court, but our legislature and executive branch know that we cannot stand to be poisoned. These companies must be held accountable, and that starts today,” said Zen Honeycutt, founder of Moms Across America and Maha leader.
Independent toxicologist Alexandra Munoz was also marching with protesters. “I’ve read the literature on glyphosate and it’s definitely a carcinogen. The evidence is really clear.”
Democratic U.S. Rep. Chellie Pingree of Maine was among many lawmakers who attended the rally. “These are issues I have been struggling with for a very long time,” Pingree told the Guardian. “It’s a big day to have a real rally in front of the Supreme Court, to have so many people from all over the country, and to have so many Republicans and Democrats united in keeping poisons out of our food, our environment, our agricultural system.”
A decision is expected this summer.
Supreme court hearing coincides with meeting of U.S. House rules committee discusses the new Farm Bill, It is officially known as H.R. 7567, the Farm, Food, and Homeland Security Act of 2026.
Pingree and Republican Rep. Thomas Massie of Kentucky last week announced a change The Farm Bill would remove provisions that would shield chemical manufacturers like Bayer from lawsuits and “prevent state and local warning label laws or use regulations for potentially harmful products.”
This story is published alongside: New LedeA journalism project of the Environmental Working Group
