Bayer Announces Petition Filing to U.S. Supreme Court for Review in Durnell Roundup Case
On April 4, 2025, Bayer AG, through its indirect subsidiary Monsanto, officially filed a petition for a writ of certiorari with the United States Supreme Court in the case of Durnell v. Monsanto. The move comes only three business days after the Missouri Supreme Court denied review of the case, thereby clearing the path for the nation’s highest court to intervene. With this filing, Bayer is seeking a definitive ruling on a fundamental legal question at the heart of tens of thousands of pending lawsuits: whether federal law preempts state failure-to-warn claims in the ongoing Roundup™ litigation.
At issue is a growing split among various federal circuit courts and state courts regarding whether plaintiffs can bring state-level failure-to-warn claims against Monsanto for not labeling Roundup™ as carcinogenic—even though such a warning is not required by, and indeed contradicts, the Environmental Protection Agency’s (EPA) regulatory assessment. Bayer argues that the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) governs the labeling of pesticide products like Roundup™, and therefore, any state-imposed requirements are expressly preempted by federal law.
A Pivotal Legal Battle With National Implications
The implications of this case reach far beyond a single plaintiff or jurisdiction. Currently, tens of thousands of Roundup™-related lawsuits are active across both state and federal courts. Each of these cases is predicated on state-level claims asserting that Monsanto failed to warn consumers that Roundup™, a glyphosate-based herbicide, may cause cancer. These claims persist despite repeated findings from the EPA and international health regulators that glyphosate is not carcinogenic when used as directed.
Bayer’s petition argues that allowing state-based claims to override federal labeling standards threatens not only legal uniformity but also the very availability of glyphosate-based products. According to the company, continued litigation risks severely disrupting the agricultural supply chain by making it economically or legally untenable for Monsanto to continue offering Roundup™ to farmers and professional applicators. Bayer contends that farmers rely on consistent, science-based labeling for crop protection products, and that this legal fragmentation endangers both food security and affordability.
The Role of FIFRA in Labeling Disputes
At the heart of Bayer’s legal argument is the preemption clause within FIFRA, which clearly states that “a State shall not impose or continue in effect any requirements for labeling or packaging in addition to or different from those required under this Act.” Bayer maintains that any state law requiring a cancer warning label on glyphosate-based products directly contradicts the EPA’s assessment and is therefore invalid under FIFRA.
The petition draws heavily on the Third Circuit Court of Appeals’ August 2024 decision in Schaffner v. Monsanto, in which the court unanimously held that the plaintiff’s state-level failure-to-warn claim was preempted by FIFRA. In that case, the court concluded that a jury verdict in favor of the plaintiff would, in effect, impose a labeling requirement different from what the EPA mandates. This decision created a direct circuit split, as the Ninth and Eleventh Circuits—as well as Missouri’s intermediate appellate court—have previously allowed similar state claims to proceed.
The Durnell Case: A Timeline
The Durnell case began with a trial in the Missouri Circuit Court for the City of St. Louis in October 2023. The plaintiff alleged that Monsanto failed to warn consumers about the potential cancer risk of Roundup™, and the jury sided partially with the plaintiff, awarding $1.25 million in compensatory damages. Notably, the jury rejected all other claims, including those seeking punitive damages.
Monsanto appealed the verdict in August 2024. However, the Missouri Court of Appeals, Eastern District, upheld the jury’s decision in February 2025. The company then promptly requested the Missouri Supreme Court to transfer the case for further review, but that court declined on April 1, 2025. With all state-level avenues exhausted, Monsanto turned to the U.S. Supreme Court, filing its petition just three business days later.
A Question of Legal Uniformity
The petition argues that state and federal courts are in urgent need of guidance from the Supreme Court due to the divergent interpretations of FIFRA’s preemption clause. Specifically, the filing asserts that the rulings in Hardeman, Carson, and Durnell all failed to consider the requirement under EPA regulations that any label change—including precautionary health warnings—must be approved by the agency before implementation.
Under current federal law, companies are not permitted to unilaterally modify labels with new warnings that contradict agency findings. Therefore, Monsanto argues, it is legally impossible to comply with both state and federal requirements simultaneously, thereby invoking the doctrine of “impossibility preemption.” This doctrine holds that when federal law makes it impossible to comply with a state law, the state law must yield.
Broader Implications Across Regulatory Landscapes
Bayer’s legal team also underscores the wider ramifications of the case, noting that several other federal statutes—including those governing medical devices, poultry, meat products, and motor vehicles—contain preemption language nearly identical to FIFRA’s. These similarities suggest that a definitive ruling from the Supreme Court could influence how courts interpret preemption clauses across multiple industries.
This is not Bayer’s first attempt to bring the issue before the Supreme Court. The company previously filed petitions in the Hardeman and Pilliod cases, which were the second and third Roundup™ cases to go to trial. However, those petitions were submitted before the Third Circuit’s favorable ruling in Schaffner, which now establishes a clear circuit split—a common and compelling reason for the Supreme Court to grant certiorari.
The Litigation Industry and the Questionable Science Behind the Claims
Bayer has also criticized the financial incentives behind the Roundup™ litigation, pointing out that plaintiff lawyers have invested hundreds of millions of dollars based primarily on a single, controversial report issued by the International Agency for Research on Cancer (IARC) in 2015. This report classified glyphosate as a “probable human carcinogen,” a finding that stands in stark contrast to the consensus of regulatory bodies around the world, including the EPA, the European Food Safety Authority, Health Canada, and others, which have consistently concluded that glyphosate does not pose a cancer risk to humans when used as directed.
Despite the scientific consensus, plaintiff attorneys continue to file lawsuits alleging Monsanto failed to warn consumers of cancer risks. Bayer argues that such claims, if left unchecked, could effectively allow a jury to override scientific determinations made by expert regulatory agencies, setting a dangerous precedent for how science and law intersect.
As the U.S. Supreme Court considers whether to take up the Durnell case, the stakes are undeniably high. A favorable ruling for Bayer could halt the wave of litigation that has plagued the company for nearly a decade, potentially saving billions of dollars in legal costs and settlement payouts. Conversely, if the Court declines to hear the case or ultimately rules against Bayer, the floodgates could remain wide open for continued litigation and potentially conflicting labeling requirements across different states.
At its core, the case represents a pivotal test of federal regulatory authority, legal uniformity, and the role of science in the courtroom. For Bayer, and indeed for the entire agrochemical industry, the outcome of this case could be transformative.
