WASHINGTON — On Monday, the Supreme Court appeared split over whether to halt numerous lawsuits claiming that the maker of the weedkiller Roundup failed to inform users of its potential cancer risk.
This case reached the justices following a surge of litigation, which includes several multibillion-dollar verdicts against Bayer, the global agrochemical giant that owns Monsanto, the producer of Roundup.
Some justices showed understanding for the company’s stance that it should not be sued under state law given that federal regulators have concluded Roundup likely does not cause cancer. Conversely, other justices questioned whether this stance unfairly prevents states from acting on evolving research.
Backed by the Trump administration, Monsanto’s legal position conflicts with certain allies in the Make America Healthy Again movement, who advocate for reduced pesticide use.
The case in question was brought by John Durnell from Missouri, who claims he developed non-Hodgkin’s lymphoma after over two decades of using Roundup in his St. Louis neighborhood. A jury found that Monsanto failed to adequately warn him of cancer risks, awarding him $1.25 million. His case is one of thousands, including some with multibillion-dollar damage awards.
The debate over glyphosate, Roundup’s key ingredient, continues. The World Health Organization’s International Agency for Research on Cancer labeled it “probably carcinogenic” in 2015, while the Environmental Protection Agency has deemed it unlikely to be carcinogenic to humans when used as directed.
The EPA approved a label lacking a cancer warning, and Bayer argues it must comply with federal standards, not the state laws Durnell and others cite in their lawsuits.
Justice Ketanji Brown Jackson pointed out that the EPA only reviews its labeling determinations every 15 years, which can be a long time given scientific advancements. Chief Justice John Roberts expressed concern over whether waiting for EPA reviews restricts 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 attorneys argue that federal law doesn’t prevent Bayer from adding a cancer risk warning under state law.
Justices Brett Kavanaugh and Elena Kagan expressed concerns that diverse state laws could complicate operations for companies and undermine federal regulations. “Do you think it’s uniformity when each state can require different things?” Kavanaugh asked.
While disputing the cancer claims, Bayer has reserved $16 billion for settlements and proposed a major settlement earlier this year. Concurrently, it has lobbied states to enact laws preventing new lawsuits, with some states agreeing.
The company has faced over 100,000 Roundup claims, predominantly from home users. It has ceased the use of glyphosate in Roundup for the U.S. residential market and warned it might withdraw glyphosate from U.S. agricultural markets if lawsuits continue.
The American Farm Bureau Federation stated in court documents that removing glyphosate would pose an “immediate, devastating risk to America’s food supply” amid existing industry pressures.
Environmental groups argue Bayer aims to avoid jury trials due to previous state court losses.
Pesticides have caused tension between the administration and Health Secretary Robert F. Kennedy’s MAHA movement, which opposes an executive order promoting glyphosate production.
Kennedy has consistently claimed glyphosate causes cancer, though he acknowledges the executive order’s importance for food supply and national security.
On Monday, MAHA activists and supporters gathered outside the Supreme Court for a “People vs. Poison” rally, protesting Monsanto’s attempts to avoid litigation.
The Supreme Court is expected to reach a decision by the end of June.
— Lindsay Whitehurst
Associated Press writer Ali Swenson in New York contributed to this report.

