The U.S. Supreme Court appeared divided Monday as it heard arguments over whether federal law shields the maker of the weedkiller Roundup from state lawsuits claiming the product caused cancer.
The case, Monsanto v. Durnell, centers on glyphosate, the key ingredient in Roundup and other herbicides once sold by Monsanto, now owned by Bayer. The chemical has been classified as a probable human carcinogen by the World Health Organization’s International Agency for Research on Cancer since 2015, though the Environmental Protection Agency maintains it is “unlikely” to be carcinogenic when used as directed.
At issue is whether the Federal Insecticide, Fungicide and Rodenticide Act, known as FIFRA, preempts state laws that allow consumers to sue companies for failing to warn users about potential cancer risks when the EPA has not required such a warning on the product label.
Attorney Paul Clement, representing Monsanto, told the justices that FIFRA’s provisions are “crystal clear” in preventing pesticide makers from altering safety warnings without EPA approval, The Guardian reported.
“Congress plainly wanted uniformity when it came to the safety warnings on a pesticide’s label,” Clement said. “Ignoring Congress’ clear direction here would open the door for crippling liability and undermine the interests of farmers who depend on federally registered pesticides for their livelihood.”
Sarah Harris, principal deputy solicitor general for the Department of Justice, argued in support of Monsanto that states cannot “second-guess or undermine” the EPA’s regulatory process, according to The Guardian.
Opposing the company, attorney Ashley Keller told the justices that “the United States is wrong” and that FIFRA does not grant the broad preemptive power Monsanto claims. He pointed to flaws in the EPA’s process, noting the agency has not updated its glyphosate registration review every 15 years as required by law.
“Things slip through the cracks with that agency,” Keller said, per The Guardian.
He also noted that the EPA’s findings on glyphosate were vacated by the 9th U.S. Circuit Court of Appeals in 2022 for failing to follow proper guidelines on cancer risk assessment.
The court’s three liberal justices appeared skeptical of Monsanto’s position, while the leanings of the others were less clear. Several justices pressed lawyers on both sides about how to handle emerging science between EPA reviews and whether it is fair to penalize a company retroactively for warnings that federal regulators did not require.
Justice Ketanji Brown Jackson observed that EPA reviews of labeling, which are required every 15 years, can be a long time in terms of the advancement of scientific knowledge. Chief Justice John Roberts asked whether that timeline means “the states cannot do anything” when new risk information emerges. Justice Brett Kavanaugh expressed concern that allowing varying state requirements would undermine federal uniformity.
A Missouri man, John Durnell, brought the case now before the court after developing non-Hodgkin lymphoma following more than 20 years of using Roundup as the volunteer “spray guy” for his St. Louis neighborhood association. A jury awarded him $1.25 million after finding Monsanto failed to warn him of possible cancer risks.
Bayer has faced more than 100,000 similar claims and has paid billions of dollars in verdicts and settlements while continuing to maintain that its products do not cause cancer. The company has set aside $16 billion for settlements and has stopped selling glyphosate-based Roundup for residential use in the U.S. It has warned that continued litigation could force it to consider removing the chemical from agricultural markets as well.
After the arguments, Bayer issued a statement thanking the court for considering FIFRA’s uniformity provisions and said it believes state warning claims “in addition to or different from” EPA-approved labels “are pre-empted” to avoid “a patchwork of 50 different warning labels.”
“Companies should not be punished under state law for complying with federal label requirements,” the company said, per The Guardian. “The security and affordability of the nation’s food supply depend on farmers’ and manufacturers’ ability to rely on the science-based judgments of federal regulators.”
Outside the court, dozens of protesters affiliated with the Make America Healthy Again movement rallied against the Trump administration’s support for Monsanto, including a recent executive order protecting glyphosate production on national security grounds. Demonstrators chanted “people over poison” and carried signs reading “Roundup the guilty” and “Make Monsanto pay.”
Zen Honeycutt, the founder of Moms Across America and a MAHA leader, said: “It’s crucial right now to show up and let not just the Supreme Court know but also our legislative branch and our executive branch that we will not stand for being poisoned … any more. These companies must have accountability and it starts today,” The Guardian reported.
Independent toxicologist Alexandra Munoz told the crowd, per The Guardian, “I’ve read the literature on glyphosate and it is definitely a carcinogen. The evidence is really clear.”
Rep. Chellie Pingree (D-ME) joined the rally, saying the turnout showed bipartisan concern.
“These are issues I’ve been fighting on for a very long time,” Pingree said, according to The Guardian. “To have an actual rally in front of the Supreme Court, to have so many people show up from all over the country and to have so many Republicans and Democrats who are united about keeping poisons out of our food, out of our environment, out of our agriculture system, it’s a big day.”
The hearing coincided with House consideration of a new Farm Bill. Last week, Pingree and Rep. Thomas Massie (R-KY) proposed an amendment that would prevent shielding chemical manufacturers from lawsuits and block the preemption of state warning-label laws.
Daniel Hinkle, senior counsel for policy at the American Association for Justice, who attended the arguments, said both sides presented strong cases.
“Both sides put on a good case,” Hinkle said, per The Guardian. “I thought they asked some serious questions and were really grappling with the implications of the case.”
The Supreme Court is expected to issue a ruling by the end of June.
