Supreme Court hears landmark Roundup case, with ruling expected to impact tens of thousands of suits

The Supreme Court will hear oral arguments Monday in Monsanto Company. v. Durnell, a closely watched case that could shape the future of tens of thousands of lawsuits alleging that Bayer-owned Monsanto’s weedkiller Roundup causes cancer.

At issue is whether federal pesticide law overrides state-level claims that Roundup’s labeling failed to warn users of potential cancer risks. The case centers on John Durnell, a Missouri man who won a $1.25 million jury verdict after arguing that long-term exposure to glyphosate (the herbicide’s active ingredient) caused his non-Hodgkin’s lymphoma.

Monsanto contends that the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) preempts such claims because the Environmental Protection Agency has not required a cancer warning on Roundup labels. A ruling in the company’s favor could significantly limit more than 100,000 similar lawsuits and carry broad implications for pesticide regulation and the agricultural industry.

The dispute highlights a broader legal tension between federal regulatory authority and state consumer protection laws. It has also produced unusual political alignments: the Trump administration’s solicitor general has backed Monsanto’s position, while some Republican state attorneys general support plaintiffs’ ability to bring failure-to-warn claims.

Advocacy groups are expected to gather outside the Court during arguments. Activists aligned with the “Make America Healthy Again” (MAHA) movement plan a rally titled “The People vs. Poison,” with scheduled speakers including Turning Point USA’s Alex Clark, Rep. Thomas Massie (R-Ky.), and activist Vani Hari.

Arguments are set to begin at 11 a.m. ET and will be livestreamed on the Supreme Court’s website. A decision is expected by the end of the Court’s term.