Bayer, Roundup, and the Supreme Court: A High-Stakes Test of Federal Preemption
Bayer AG has spent years defending thousands of lawsuits stemming from glyphosate, the active ingredient in Roundup—the widely used herbicide it acquired through its 2018 purchase of Monsanto. Plaintiffs allege that prolonged exposure to glyphosate causes non-Hodgkin lymphoma and claim Monsanto, and now Bayer, failed to adequately warn consumers of that risk.
Despite the Environmental Protection Agency’s (EPA) consistent conclusion that glyphosate is not a human carcinogen—and its continued approval of Roundup’s labeling—juries across the country have returned sizable verdicts against Bayer. The company has already resolved more than 114,000 claims, paying over $11 billion in settlements, but litigation continues. Recent verdicts, including one for $2.1 billion, have placed renewed legal and financial pressure on Bayer.
Now, the company is asking the U.S. Supreme Court to intervene and decide a fundamental legal question: Does federal law preempt state-law failure-to-warn claims concerning EPA-approved pesticide labels?
The Legal Dispute: Failure to Warn and FIFRA Preemption
At the heart of the Roundup litigation is a clash between state tort law and federal regulatory authority. Plaintiffs argue that Bayer failed to warn users about the alleged cancer risks associated with glyphosate. They claim that, had Roundup’s labeling included a cancer warning, they would have changed or avoided its use.
Bayer counters that it was legally prohibited from adding such a warning. Under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), the EPA must review and approve all pesticide labeling. The EPA has repeatedly declined to require a cancer warning for glyphosate—and has in fact rejected such efforts. Bayer argues that holding it liable under state law for failing to add a warning the EPA has explicitly found unnecessary would place the company in an untenable legal position and undermine federal regulatory authority.
According to Bayer, such state-law claims are preempted by FIFRA and the Supremacy Clause of the U.S. Constitution.
A Growing Circuit Split
Bayer’s certiorari petition in Monsanto Co. v. Durnell (No. 24-1068) comes amid a widening circuit split on the preemption question.
- The Third Circuit ruled in Bayer’s favor, holding that FIFRA preempts state-law claims challenging EPA-approved labels.
- The Ninth and Eleventh Circuits, however, have allowed such claims to proceed, reasoning that state tort law can supplement federal regulation by providing additional consumer protections.
- Several state courts have taken similar approaches, allowing failure-to-warn claims to go forward.
This split has created considerable legal uncertainty—not only for Bayer, but for manufacturers across industries whose products are regulated at the federal level. Bayer is now urging the Supreme Court to resolve the conflict and establish a uniform national standard governing the intersection of federal labeling regulations and state tort claims.
Bayer’s Argument to the Court
In its petition, Bayer argues that the EPA’s longstanding judgment that glyphosate does not require a cancer warning preempts any conflicting requirements under state law. It cannot be held liable, the company contends, for failing to provide a warning that federal regulators have deemed unnecessary and even misleading.
Allowing state courts and juries to impose liability in spite of EPA decisions, Bayer says, would effectively dismantle the uniform regulatory framework established by FIFRA and create a confusing, inconsistent patchwork of legal obligations. The company frames the issue as one of regulatory coherence and constitutional balance, warning that without Supreme Court intervention, businesses will face incompatible federal and state standards—particularly in areas like product labeling, where consistency is essential.
What Comes Next?
The Supreme Court is scheduled to review Bayer’s petition during its private conference on June 26, 2025. Several outcomes are possible:
- Granting certiorari would set the stage for briefing and oral argument during the 2025–2026 term, with a decision likely by summer 2026.
- Denying review would allow conflicting lower court rulings to stand and permit Roundup cases to proceed under varying state-law standards.
- Calling for the views of the Solicitor General or granting review on a narrower question remains a third option.
Regardless of the Court’s path, its decision—or decision not to act—will have broad implications for regulatory law, tort liability, and future mass tort litigation.
Conclusion: A Case with Nationwide Impact
Monsanto v. Durnell may determine the future trajectory of one of the largest mass tort litigations in U.S. history. A ruling in Bayer’s favor could limit the ability of plaintiffs to bring state-law failure-to-warn claims against companies whose products are federally regulated—impacting not just pesticide manufacturers, but industries as diverse as pharmaceuticals, chemicals, and consumer goods.
On the other hand, a denial of review would maintain the status quo: continued litigation in state courts, inconsistent liability standards across jurisdictions, and legal exposure for companies operating in a highly regulated environment.
Either way, the case is shaping up to be a pivotal moment in the ongoing debate over federal preemption, state tort law, and the balance of power in American product regulation. Manufacturers, legal professionals, and public health advocates alike will be watching the Court’s next move with intense interest.
