The Supreme Court appeared sharply divided Monday over whether federal pesticide law shields Bayer from state-level lawsuits alleging its Roundup weedkiller should have carried a cancer warning, a case that could determine the fate of more than 100,000 similar claims and billions of dollars in potential liability.
The justices heard oral arguments in Monsanto v. Durnell, a dispute that pits the federal government's authority over pesticide labeling against the right of individual states, and individual juries, to hold manufacturers accountable when new science raises health alarms the EPA has not yet acted on. The question is straightforward: does the Federal Insecticide, Fungicide, and Rodenticide Act preempt state failure-to-warn claims when the EPA never required a cancer warning on the label?
The answer will reach far beyond one Missouri plaintiff. It will set the boundary between federal regulatory power and the ability of ordinary Americans to seek justice in their own state courts when a product they used for decades may have given them cancer.
John Durnell alleged that years of glyphosate exposure caused his non-Hodgkin's lymphoma. In 2019, a Missouri jury agreed and awarded him $1.25 million in damages. A Missouri appellate court sided with Durnell, and the state Supreme Court declined to take up Monsanto's second appeal.
Monsanto, now owned by Bayer, asked the U.S. Supreme Court to step in. The company's argument rests on a single statutory phrase. FIFRA says no state "shall impose or continue in effect any requirements for labeling or packaging in addition to or different from those required under" federal law. Because the EPA approved Roundup's label without a cancer warning, Bayer contends, Missouri cannot force one through the back door of tort liability.
The Justice Department lined up alongside Bayer, arguing that FIFRA gives the EPA final authority on labeling requirements for pesticides under its jurisdiction. That alignment, the Trump administration's DOJ backing a major agrochemical company against a cancer plaintiff, adds a layer of political complexity, particularly as the Make America Healthy Again movement pushes for tighter restrictions on chemicals in food and farming.
The Court's recent term has already produced sharp divisions on questions of executive power and federal preemption, and Monday's arguments showed this case will be no exception.
Paul Clement, representing Monsanto, built his case around the word "under" in FIFRA's preemption clause. He compared the statute's language to the medical-device preemption provision at issue in the Court's 2008 ruling in Riegel v. Medtronic.
Clement told the justices:
"But the language of FIFRA's preemption provision, just like the language of the preemption provision for the medical device amendments that were at issue in the Riegel case, both of those uses the word 'under,' and I think that word textually captures the various requirements that are imposed at a device-specific level or a herbicide-specific level in the context of the registration process here."
Ashley Keller, arguing for Durnell, met the textualist framing head-on. He accepted the importance of statutory text but drew a hard line between EPA registration and EPA labeling requirements, two different things, he insisted.
"Monsanto's problem is they're not relying on any of those regulations. They are relying on registration and registration alone. There is nothing in, by, under, or next to FIFRA that makes the registration decisions that EPA makes binding labeling requirements with preemptive force."
That distinction, registration versus labeling, became the fault line of the argument. If EPA registration alone carries preemptive force, then no state jury can ever second-guess a label the EPA approved, even if the science has moved on. If registration is merely an entry ticket and not a binding endorsement of every word on the label, then state tort claims survive.
Justice Brett Kavanaugh appeared the most sympathetic to Bayer's position. He pressed Keller on the practical problem facing a manufacturer caught between federal approval and state liability, framing it as a retroactivity concern.
"I think you're saying that EPA can change requirements going forward, but if it tries to say you were misbranding when you did what they told you, that's a retroactivity problem of sorts, in the sense that they're penalizing you retroactively for something that is now required."
Kavanaugh also asked a pointed question that cut to the core of the preemption issue: "Under federal law, if they do a different label than what EPA has approved, would they be violating federal law?" The implication was clear, if Monsanto cannot legally change its own label without EPA permission, holding it liable for not changing the label creates an impossible bind.
But Kavanaugh also pushed back on the uniformity argument in a way that complicated Bayer's position. As Breitbart reported, the justice asked Clement directly: "Do you think it's uniformity when each state can require different things?"
Chief Justice John Roberts raised perhaps the sharpest concern about Bayer's argument. As the Associated Press reported, Roberts asked: "Throughout that long process, in response to information that suggests there is a risk that's not on the label, the states cannot do anything?"
That question matters. If the EPA takes years, or decades, to update a label, and new science suggests a product may cause cancer, are states simply powerless in the interim? For conservatives who value federalism and the right of states to protect their own citizens, Roberts's question lands with real force.
Justice Ketanji Brown Jackson appeared the most skeptical of Bayer's argument. She noted the long gap between EPA reviews:
"There's a 15-year window between when that product has to be registered again, and lots of things can happen in science in terms of development of the product."
Justices Neil Gorsuch and Amy Coney Barrett also pressed Clement during the argument, and the Court's internal divisions have been on public display throughout this term on a range of contentious issues. Clement reportedly offered conflicting answers under their questioning, a sign that Bayer's legal theory may not hold together as neatly as the company hoped.
At the heart of the case sits a genuine scientific disagreement. In 2015, the International Agency for Research on Cancer, a working group of the World Health Organization, classified glyphosate as "probably carcinogenic to humans." The EPA, by contrast, has maintained that glyphosate is "not likely to be carcinogenic" when used as directed.
That regulatory split is not academic. Roughly 280 million pounds of glyphosate are sprayed onto nearly 300 million acres of American farmland every year, according to the EPA. Glyphosate is the most common weedkiller in the United States. If the Court rules for Bayer, it could effectively immunize the company, and the entire pesticide industry, from state-level accountability for labeling decisions, so long as the EPA has signed off.
Keller argued that the FDA comparison cuts against Bayer. He noted that even after the FDA approves a drug's label, the agency still recognizes that a drug can be misbranded if new information emerges.
"The FDA agrees that post-NDA application, post-approval, you can still have a misbranded drug. It shouldn't be less protective of consumers under the context of FIFRA, where the EPA is operating, with less information on those points."
Clement countered with a warning about the chaos of 50 different state standards, or worse. "On uniformity, it's worse than 50 states. It's every jury is a new day," he told the justices.
Keller's response drew a careful line. He acknowledged the need for "uniformity in the law" but argued that legal uniformity does not mean factual uniformity: "The law of Missouri and the law of the United States have to be the same.... It does not require fact finders to find the facts the same way."
The financial exposure is staggering. The Washington Times reported that Bayer has faced more than 100,000 Roundup claims and has set aside $16 billion to settle cases. The company has warned that ongoing litigation could affect glyphosate's future in U.S. markets.
A ruling for Monsanto could sharply limit those lawsuits, as Just The News noted, carrying broad implications for pesticide regulation and the agricultural industry. A ruling for Durnell would leave the floodgates open, and signal that EPA registration alone does not give manufacturers a free pass on state liability.
The political dimensions are hard to ignore. A Politico poll from early April found that nearly 7 in 10 Americans support greater restrictions on pesticide use. The case has created tension inside the broader Trump coalition, with MAHA activists who oppose widespread glyphosate use finding themselves at odds with the administration's DOJ, which sided with Bayer.
The future composition of the Court could shape how cases like this are decided for a generation. But for now, the current nine justices will determine whether Americans like John Durnell can hold manufacturers accountable in state court, or whether a federal agency's approval of a label is the last word.
The Court is expected to issue its ruling by the end of June.
This case is not just about one weedkiller or one plaintiff. It is about whether federal regulators can, by inaction, strip citizens of their right to hold corporations accountable under state law. The EPA did not require a cancer warning. It also did not prohibit one. The question is whether that silence becomes a shield.
For conservatives who believe in limited federal power and robust state sovereignty, the answer should not be automatic. Federalism means something. So does the right of a jury to hear the evidence and render a verdict.
The Court has shown this term that it is willing to revisit settled assumptions. The question in Monsanto v. Durnell is whether it will side with a regulatory bureaucracy's silence, or with the people who have to live with the consequences.
When a federal agency takes 15 years between reviews, telling Americans they have no recourse in the meantime is not uniformity. It is abandonment.
