The Supreme Court appeared divided Monday over whether federal regulatory approval should protect Bayer from thousands of state lawsuits claiming its Roundup weedkiller causes cancer, a case with profound implications for product liability law and the authority of federal agencies. The case follows a wave of litigation that has resulted in some multibillion-dollar verdicts against the global agrochemical manufacturer that owns Roundup maker Monsanto.
Several justices seemed sympathetic to Bayer's core argument: that it cannot be sued under state law because the Environmental Protection Agency has determined Roundup likely does not cause cancer. The company contends it is required to follow federal labeling standards, not state laws under which plaintiffs have successfully sued. Other justices questioned whether blocking state lawsuits would inappropriately prevent states from responding to evolving scientific research.
The Case and the Stakes
The lawsuit before the court was filed by Missouri resident John Durnell, who claimed he developed non-Hodgkin's lymphoma after more than 20 years of using Roundup on parks in his St. Louis community as the neighborhood association's "spray guy." A jury found the company failed to warn him about possible cancer dangers and awarded him $1.25 million. His case represents one of thousands of similar claims, including some resulting in multibillion-dollar damage awards.
Bayer has faced more than 100,000 Roundup claims, mostly from home users, and has set aside $16 billion to settle cases. The company proposed a major settlement earlier this year and has lobbied states to pass laws barring new cases, with a few agreeing. Bayer has already stopped using glyphosate in Roundup sold in the U.S. residential lawn and garden market and has indicated it might consider pulling the chemical from U.S. agricultural markets if the lawsuits persist.
The Scientific and Regulatory Divide
Fierce debate continues about cancer risks associated with Roundup's key ingredient, glyphosate. The World Health Organization's International Agency for Research on Cancer classified the chemical as "probably carcinogenic" in 2015, 11 years ago. However, the Environmental Protection Agency has determined that glyphosate is not likely to be carcinogenic to humans when used as directed. The EPA approved a label without a cancer warning, forming the basis of Bayer's legal defense.
Justice Ketanji Brown Jackson noted that EPA reviews its labeling determinations every 15 years, which can be a relatively long period in terms of scientific advancement. Chief Justice John Roberts questioned whether waiting for EPA review ties the hands of state courts. "Throughout that long process, in response to information that suggests there is a risk that's not on the label, the states cannot do anything?" he asked.
Durnell's lawyers argued that federal law does not stop Bayer from putting a warning about possible cancer risk on its products under state law. Justices Brett Kavanaugh and Elena Kagan both expressed concern that facing liability under different state laws could make it difficult for companies and undermine the purpose of federal regulations. "Do you think it's uniformity when each state can require different things?" Kavanaugh said.
Agricultural and Political Implications
The American Farm Bureau Federation stated in court documents that removing glyphosate from the market would have an "immediate, devastating risk to America's food supply" at a time when the industry is already under pressure. Environmental groups say Bayer wants to keep juries out of the lawsuits because of its state court losses.
Roundup maker Monsanto is backed by the Trump administration, a legal position that is at odds with some allies in the Make America Healthy Again movement who want to rein in pesticide use. Health Secretary Robert F. Kennedy has said repeatedly that glyphosate causes cancer, even as he says he recognizes an executive order aimed at boosting glyphosate's production was necessary for food supply and national security reasons. Pesticides have created a rift between the administration and members of Kennedy's MAHA movement, who were also frustrated with the executive order.
Dozens of MAHA activists and supporters gathered outside the Supreme Court on Monday for what they called a "People vs. Poison" rally to decry Monsanto's efforts to shield itself from lawsuits. The Supreme Court is expected to decide the case by the end of June.
Why This Matters:
This case tests fundamental questions about regulatory authority and the proper balance between federal oversight and state tort law. If the Court sides with Bayer, it would affirm that EPA approval provides meaningful protection from state-level liability, strengthening the regulatory framework businesses rely on for compliance certainty. Such a ruling would prevent companies from facing conflicting requirements across 50 states, reducing litigation costs that ultimately get passed to consumers and farmers. However, it would also limit states' traditional authority to protect their citizens through tort law when new evidence emerges between federal review cycles. The outcome will determine whether federal agencies or state juries have the final word on product safety warnings, with significant consequences for agricultural productivity, food costs, and the predictability of the legal environment for American manufacturers.