Supreme Court will decide if federal law blocks Roundup failure-to-warn suits

The Supreme Court agreed to hear Bayer AG’s appeal challenging thousands of state-court lawsuits that allege the company’s glyphosate-based weedkiller Roundup caused cancer and that Monsanto, now owned by Bayer, failed to warn users. At the center of the case is whether federal pesticide law, including Environmental Protection Agency decisions and the Federal Insecticide, Fungicide, and Rodenticide Act preemption doctrine, bars state-law failure-to-warn claims.

The appeal stems from a Missouri lawsuit in which a jury awarded $1.25 million to John Durnell, who said he developed non-Hodgkin’s lymphoma after years of spraying Roundup in parks and a community garden near his St. Louis home. Durnell sued Monsanto in 2019; the contested 2023 verdict was later upheld by a Missouri state appeals court. Bayer asked the high court to rule that some claims in the case are preempted by federal law and to resolve what it says are conflicting decisions in lower courts.

Bayer’s principal contention is that FIFRA and the EPA’s determination that a cancer warning was not required for glyphosate preempt state-law duties to provide additional labeling or warnings. The company argues that allowing state courts to impose labeling obligations beyond the federally approved label would conflict with Congress’s design for federal oversight of pesticides. Bayer has framed Supreme Court review as necessary to resolve circuit splits, citing a 2024 Third Circuit decision that ruled in Bayer’s favor on preemption grounds while noting other state and federal appellate rulings have allowed substantial state-law verdicts to stand.

The litigation is vast. Bayer faces roughly 181,000 Roundup claims, mostly from residential users, and settled nearly 100,000 suits by fall 2025 as part of an approximately $11 billion effort to resolve much of the litigation after acquiring Monsanto in 2018. Bayer has said it stopped using glyphosate in Roundup products sold to U.S. residential lawn-and-garden consumers, while glyphosate remains in agricultural formulations designed for use with genetically modified seeds. Company officials have warned they might consider withdrawing glyphosate from U.S. agricultural markets if litigation persists.

The Court has asked the Justice Department for its views on whether the case should be heard or resolved, a step that signals the justices expect significant federal interests to be implicated. The timing of oral argument is unclear; the Court could schedule arguments in the spring or at the start of the next term in October. A ruling in Bayer’s favor could narrow or eliminate many failure-to-warn claims, while a decision for plaintiffs could preserve state-court remedies and leave thresholds for state tort liability intact.

The decision has drawn sharp reactions from advocacy groups and the company. Lori Ann Burd, environmental health director at the Center for Biological Diversity, called the Court’s decision to take the case “a sad day in America” and warned it could deprive thousands of cancer sufferers of their day in court. Bayer said the Court’s decision to take the case was “an important step in our multi-pronged strategy to significantly contain this litigation.” The coming ruling will test the balance between federal regulatory authority and state tort remedies, with implications for public health accountability, agricultural practice and product-labeling law.