The U.S. Supreme Court issued a major decision on Thursday, ruling 7-2 in favor of Monsanto and its parent company, Bayer. The landmark opinion significantly alters the landscape of agricultural litigation by blocking thousands of pending and future lawsuits that claim the weedkiller Roundup causes cancer.
The decision in Monsanto v. Durnell centers on a legal concept known as federal preemption. The high court ruled that the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) explicitly prevents states from establishing labeling requirements that are “in addition to or different from” federal standards.
Because the U.S. Environmental Protection Agency (EPA) reviews the safety of glyphosate—the active ingredient in Roundup—and has consistently determined that it is unlikely to be carcinogenic to humans, the federal agency does not require a cancer warning on the product label. The Supreme Court ruled that state-level “failure-to-warn” lawsuits effectively try to force a warning label that contradicts the EPA’s federal standard, meaning such claims are legally barred.
Justice Brett Kavanaugh delivered the majority opinion, which drew broad support from justices across the ideological spectrum.
“Because Durnell’s state tort claim would impose a pesticide labeling requirement ‘in addition to or different from’ the label required by EPA, FIFRA expressly preempts Durnell’s claim,” Kavanaugh wrote.
The case originated with John Durnell, a St. Louis, Missouri resident who used Roundup for decades to maintain public parks. After developing non-Hodgkin lymphoma, Durnell sued Monsanto, arguing the company failed to warn consumers about potential cancer risks. A Missouri state jury subsequently awarded Durnell a $1.25 million verdict, which Bayer appealed all the way to the nation’s highest court. The decision effectively reverses that lower court victory.
Justice Ketanji Brown Jackson authored the dissenting opinion, which was joined by Justice Neil Gorsuch. Jackson argued that the majority misunderstood the relationship between state and federal oversight, stating that federal law limits but does not entirely eliminate a state’s authority to regulate pesticide labels. She noted that the ruling ultimately leaves individuals who have suffered significant harm without a viable legal remedy.
The legal victory provides massive financial and structural relief for Germany-based Bayer, which acquired Monsanto in 2018. Over the last decade, the company has faced roughly 180,000 lawsuits linking Roundup to cancer, leading to more than $11 billion in paid settlements and individual jury verdicts. An estimated 61,000 cases remain active in courts nationwide.
Bayer CEO Bill Anderson praised the ruling, noting that it restores critical regulatory certainty for innovators and agricultural producers who rely on uniform federal standards. The company stated the ruling should lead directly to the dismissal of the vast majority of current warning-based claims and prevent similar lawsuits in the future.
Conversely, environmental and public health advocacy organizations expressed deep concern over the outcome. Legal experts from the non-profit group Earthjustice warned that treating EPA label approval as an absolute legal shield for manufacturers creates a dangerous precedent, reducing corporate accountability even when independent scientific findings suggest potential health risks.
