A St. Louis jury began hearing a new Roundup case on Tuesday that could help define which product-liability claims remain viable after the U.S. Supreme Court limited warning-label lawsuits earlier this year. The plaintiffs are three women who allege that regular use of Monsanto’s herbicide caused non-Hodgkin lymphoma and that the product was defectively designed and inadequately tested, according to Reuters’ account of opening statements. Bayer, which owns Monsanto, denies that glyphosate-based herbicides cause cancer.
The legal distinction matters. In Monsanto Co. v. Durnell, the Supreme Court held in June that federal pesticide law preempted a Missouri failure-to-warn claim premised on the absence of a cancer warning from Roundup’s label. The court’s 7-2 opinion said manufacturers must use the label approved by the Environmental Protection Agency and cannot independently add a warning that conflicts with that federal approval. The current St. Louis case instead centers on design-defect and testing theories that the June ruling did not directly resolve.
That does not mean the new plaintiffs have established liability. Theresa Aretino, Cynthia Fernandez and Betty Larkin must prove their claims under the evidence and instructions presented at trial; Fernandez died before proceedings began, Reuters reported. Bayer’s lawyers told jurors that decades of regulatory reviews support the product’s safety. The company has made the same position central to its broader litigation strategy, including when it announced that a Missouri court had given preliminary approval to a proposed nationwide class settlement in March.
Federal regulators remain part of the dispute. The EPA says its 2020 interim review found no human-health risks when glyphosate is used as directed and judged it unlikely to be carcinogenic, while also identifying ecological risks and requiring mitigation. The agency is updating that evaluation after a federal appeals court in 2022 required additional analysis. The Food and Drug Administration likewise directs consumers to EPA’s risk assessment while describing its own role in testing food for pesticide residues.
The trial also unfolds alongside a separate Missouri proceeding over Bayer’s proposed $7.25 billion settlement framework for many existing and future Roundup claims. A September 14 fairness hearing in St. Louis drew competing arguments from lawyers who said the plan could deliver compensation and others who said it would constrain claimants. The three women in the new trial are not participating in that proposed settlement.
For Missourians, the immediate point is procedural rather than a new safety directive: the jury has heard opening statements, not reached a verdict, and neither the trial nor the settlement proceeding changes the current EPA-approved label. The case’s broader importance lies in whether a Missouri jury accepts liability theories that survive outside the warning-label question the Supreme Court decided. Any verdict could be appealed, so the first result may be an important signal rather than the final word.
