Key Takeaways:
- Bayer, through subsidiary Monsanto, filed a petition with the U.S. Supreme Court following a Missouri Supreme Court decision in the Durnell case.
- The company argues that federal law preempts state failure-to-warn claims under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA).
- A circuit court split has emerged, with differing interpretations from the 3rd, 9th, and 11th Circuits.
- Bayer asserts that differing state rulings could result in conflicting labeling requirements for glyphosate-based products.
- The outcome may influence tens of thousands of pending Roundup™ cases in federal and state courts.
Bayer Monsanto Seeks Supreme Court Review Following Missouri Ruling
Bayer, through its indirect subsidiary Monsanto, has submitted a petition for a writ of certiorari to the U.S. Supreme Court in connection with the Durnell case, which centers on product labeling and liability issues related to the herbicide Roundup™. The petition was filed three business days after the Missouri Supreme Court declined to review the appellate court’s decision upholding a $1.25 million verdict against the company for failure to warn of potential health risks.
The company contends that the ruling raises a fundamental legal issue regarding whether federal pesticide regulations under FIFRA preempt state-based failure-to-warn claims. The verdict in Durnell rested solely on a Missouri law requirement that Monsanto provide a cancer warning on Roundup™—a warning that the U.S. Environmental Protection Agency (EPA) has not required.
Federal Preemption and Conflicting Court Rulings
Monsanto argues that federal preemption should apply, citing the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), which prohibits states from imposing labeling requirements that are “in addition to or different from” those mandated by the EPA. According to the company, a jury finding that Missouri law requires a cancer warning directly contradicts the EPA-approved label and is therefore preempted.
The petition highlights conflicting decisions among U.S. circuit courts. The Third Circuit ruled in favor of Monsanto in Schaffner in August 2024, finding that FIFRA preempted the plaintiff’s failure-to-warn claim. However, rulings in Hardeman, Carson, and Durnell reached different conclusions. Monsanto argues that this split requires resolution by the Supreme Court to ensure consistency in federal labeling laws and avoid the possibility of state-specific labeling requirements for federally regulated products.
Bayer Highlights Regulatory Consistency and Implications for Agriculture
In its petition, Bayer maintains that allowing states to mandate different health warnings could undermine regulatory uniformity and disrupt national commerce. The company emphasized that glyphosate-based products like Roundup™ are widely used by farmers and other professional applicators who depend on uniform, science-based labels approved by federal authorities.
The petition also draws attention to preemption clauses in other federal laws governing medical devices, motor vehicles, and food products, noting that consistent judicial interpretation across regulatory frameworks is important.
Monsanto claims that litigation efforts targeting Roundup™ rely on a decade-old report that diverges from evaluations by the EPA and other international regulatory agencies, which have not classified glyphosate as carcinogenic.
Background on the Durnell Case and Broader Legal Context
The Durnell case was tried in October 2023 in Missouri Circuit Court, where the jury found Monsanto liable for failure to warn but did not award punitive damages. The Missouri Court of Appeals affirmed the verdict in February 2025. After the state supreme court declined further review, Monsanto moved quickly to request consideration by the U.S. Supreme Court.
This marks Monsanto’s third such petition in the Roundup™ litigation. Previous requests in the Hardeman and Pilliod cases were filed before the Third Circuit’s decision in Schaffner, which the company argues now establishes a split among circuits.
Bayer is seeking a definitive ruling that could impact the trajectory of tens of thousands of similar cases currently pending in state and federal courts.
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