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In 2018, a jury awarded Dewayne Johnson, a former groundskeeper with non-Hodgkin’s lymphoma (a type of blood cancer), $289 million—later reduced to $20.4 million. In California, juries awarded the Pilliod couple $2.055 billion, later reduced to $87 million. John Durnell spent years spraying Roundup weedkiller in Missouri parks, trusting that regulatory authorities had vetted the product. After developing non-Hodgkin’s lymphoma, he sued Monsanto, now owned by Bayer. In October 2023, a St. Louis jury awarded him $1.25 million, finding that the company should have warned him about cancer risks regardless of what federal regulators approved.
That verdict sits at the center of a legal collision between two ways of determining what’s safe. One approach relies on the EPA’s scientific assessments, conducted by scientists who study how chemicals affect health and disease patterns in populations over months or years. The other depends on state court juries who hear competing experts and make their own judgments.
The U.S. Supreme Court will soon decide whether the Environmental Protection Agency gets the final word on chemical safety—or whether ordinary people can still sue companies for injuries when they believe a product made them sick. The case is Monsanto Company v. Durnell, and it centers on a question that could reshape decades of product liability law: When federal regulators say a chemical is safe, does that decision stop a jury from reaching a different conclusion after hearing the evidence themselves? The Supreme Court’s decision will determine which system has more authority to protect—or fail to protect—the public.
How the EPA Decides What’s Safe
The EPA doesn’t ask whether a chemical is perfectly harmless. Instead, the agency operates under the federal pesticide safety law, which requires a different question: whether a pesticide will cause harmful effects that outweigh the benefits when used according to label directions.
The EPA weighs risks against benefits. A chemical that poses some danger might still get approved if it offers substantial agricultural or public health advantages. For glyphosate, the active ingredient in Roundup, that calculus has consistently favored approval. The herbicide transformed modern farming when it emerged in the 1970s—a broad-spectrum weed killer that could be used with genetically modified crops, enabling no-till agriculture that reduces soil erosion and fuel consumption.
The approval process involves layers of review. When pesticides come up for re-registration every fifteen years, manufacturers must submit updated studies. Scientists examine animal studies testing for tumors, data from tracking people’s health over time, and research into how chemicals work at the cellular level. The agency publishes detailed risk assessments explaining which studies it evaluated and why it reached its conclusions.
For cancer specifically, the EPA follows established protocols. A single study suggesting possible cancer effects doesn’t automatically trigger a warning label. The agency asks whether the totality of evidence—across animal studies, human epidemiology, and cellular mechanisms—supports concluding that the chemical poses cancer risk at realistic exposure levels.
The agency uses cautious assumptions that lean toward safety when data is incomplete. If mice develop tumors at high doses, the agency might assume humans could be affected at lower doses. If evidence is ambiguous, the agency leans toward caution. When animal studies show no tumors, when heavily exposed workers show no cancer clusters, when laboratory research finds no plausible cancer mechanism, the EPA concludes cancer risk isn’t established.
That’s where the agency has landed on glyphosate, repeatedly, through both Republican and Democratic administrations: while individual studies might suggest possible associations, the overall weight of evidence doesn’t support classifying glyphosate as likely to cause cancer.
Why Other Scientific Bodies Disagree
In 2015, the International Agency for Research on Cancer classified glyphosate as likely to cause cancer. This determination, from a specialized WHO agency, created public confusion and fueled the Roundup litigation. Plaintiffs pointed to the IARC classification as evidence that regulatory agencies knew about cancer risks Monsanto had failed to disclose.
The EPA and IARC reached different conclusions about the same evidence because each organization pursues a different mission. IARC’s job is to flag chemicals that might cause cancer so researchers can study them. The organization uses a formal classification system ranging from “definitely carcinogenic” to “probably not carcinogenic.” This approach focuses on whether any evidence suggests a chemical might cause cancer—a lower bar than the EPA’s question of whether evidence supports requiring a warning label with legal and commercial consequences.
The difference shows up in how each handles uncertainty. IARC might classify a substance as “possibly carcinogenic” based on limited evidence, precisely because flagging potential carcinogens is central to its research mission even when evidence is incomplete. By contrast, the EPA must make a concrete regulatory decision: require a warning or don’t. That demands asking whether available evidence supports concluding that exposure poses risk to humans.
When IARC examined glyphosate, it noted studies of disease patterns in exposed populations suggesting associations between glyphosate exposure and non-Hodgkin’s lymphoma. The panel determined there was sufficient evidence of carcinogenicity in animals and limited evidence in humans, so IARC labeled it “probably carcinogenic.” But this didn’t reflect consensus that glyphosate definitely causes human cancer—it reflected IARC’s assessment that evidence was sufficient to list the chemical as a potential carcinogen worth further study.
Examining the same and subsequent studies, the EPA concluded the evidence was too limited and inconsistent to justify regulatory action. The scientific literature on glyphosate’s cancer potential remains contested. Some scientists argue the EPA’s methodology is insufficiently protective and gives inadequate weight to studies of disease patterns in exposed populations suggesting associations between glyphosate and non-Hodgkin’s lymphoma among agricultural workers. Others argue the epidemiological evidence is weak and could be explained by exposure to other chemicals instead of genuine glyphosate effects.
A scientific journal retracted a landmark study in 2025 that had concluded glyphosate is safe, citing ethical concerns about Monsanto employee involvement. The retraction doesn’t necessarily invalidate the study’s conclusions, but it undermines public confidence in the regulatory process.
The Legal Question: Can Federal Approval Shield Companies from State Courts?
The federal pesticide law contains a rule that says states can’t require different labels than what the federal government requires. Monsanto’s argument, endorsed by the Trump administration’s Justice Department, is straightforward: if the EPA determined glyphosate doesn’t require a cancer warning, allowing state court juries to require one through tort lawsuits violates the rule about federal law overriding state law.
Lower courts have split on how to apply this question. Some courts have reasoned that the federal pesticide law’s purpose is creating uniform national standards rather than allowing fifty states to impose different labeling regimes. If manufacturers face tort liability for not including warnings the EPA has rejected as scientifically unwarranted, they can’t meaningfully comply with federal law.
Other courts reached contrary conclusions. The Missouri Court of Appeals, which upheld Durnell’s verdict, found no “clear evidence” that the EPA would have rejected a cancer warning if Monsanto had proposed one. Plaintiff’s lawyers made a more aggressive argument: that Durnell’s case wasn’t truly about the label but about Monsanto’s advertising and marketing that goes beyond what the EPA-approved label says, which represented the product as safe to use without protective equipment. If the case rests on marketing claims rather than label adequacy, state tort law should apply freely.
Different appeals courts reached opposite conclusions—precisely why the Supreme Court took the case. The Court will decide whether federal law preempts a label-based failure-to-warn claim where the EPA hasn’t required the warning.
Why Juries Keep Siding Against Monsanto
Durnell’s $1.25 million verdict isn’t an outlier. It’s part of a pattern. These verdicts raise a puzzle for the legal rule about federal law overriding state law. If the EPA’s scientific determination is supposed to be final and binding, why do juries regularly reject it?
In jury trials, plaintiffs present expert scientists who testify that glyphosate exposure causes cancer and that the company should have warned about it. Defense experts testify for the company. But juries aren’t bound to accept either expert’s view—they assess credibility, reasoning, persuasiveness.
More significantly, juries in Roundup cases have seen internal company documents obtained through discovery where Monsanto scientists and executives discussed potential cancer risks and concerns about scientific research, including allegations of ghostwritten studies. Some documents suggested the company was concerned about litigation risk based on glyphosate’s cancer potential, even as regulatory agencies continued determining that cancer warnings were unwarranted.
Whether these internal documents establish that the company knew of cancer risks more clearly than disclosed, or instead show the company was aware of litigation concerns, is subject to interpretation. But their existence in the trial record influences juries, particularly combined with expert testimony suggesting possible mechanisms by which glyphosate might cause non-Hodgkin’s lymphoma.
Juries assess evidence according to their own judgment. They may discount regulatory determinations based on worries that the EPA has been influenced by industry interests, or that the EPA’s approach to testing chemicals is too cautious in refusing to find cancer risks. They may be persuaded by alternative scientific arguments or by testimony from academic experts critical of the EPA’s assessment.
What’s at Stake
From Monsanto and the business community’s perspective, the issue is straightforward: the federal pesticide law set up the EPA as the main decision-maker for pesticide safety, and allowing state courts to challenge the EPA’s scientific decisions defeats the law’s purpose. Bayer CEO Bill Anderson stated that “it is time for the U.S. legal system to establish that companies should not be punished under state laws for complying with federal warning label requirements.”
If manufacturers can’t rely on EPA approval to shield them from tort liability, they face potentially unlimited exposure across fifty different state legal standards. The Trump administration’s chief lawyer before the Supreme Court warned that allowing Durnell’s verdict to stand would leave manufacturers to face 50 different state labeling requirements and would mean companies could be sued in state courts for complying with federal law, or they must face federal civil or criminal liability for knowingly violating federal law to comply with state tort law.
The Trump administration’s backing of Monsanto represents a significant policy shift. The administration urged the Supreme Court to take the case and rule in Monsanto’s favor, reversing the position taken by the Biden administration’s Solicitor General in 2022, who had argued that the federal pesticide law doesn’t preempt such claims. HHS Secretary Robert F. Kennedy Jr. previously served as a lead attorney in high-profile Roundup lawsuits and won substantial jury verdicts for cancer victims, a position that contradicts the administration’s current support for Monsanto.
From the plaintiff’s perspective and that of public health advocates, allowing federal law to override state lawsuits could harm consumer protection. Earthjustice warned that “If the Supreme Court agrees with the chemical industry, pesticide companies could avoid being sued simply because the EPA approved their labels at some point in the past, even if the company concealed how harmful their pesticides were to people.” The organization emphasized that if federal law completely overrides state lawsuits, companies could “ignore new science, withhold evidence they obtain about the harm caused by their pesticides, and still avoid responsibility when people get sick.”
Durnell’s attorneys emphasized that he relied on Monsanto’s advertising and marketing that goes beyond what the EPA-approved label says and represented that the product was safe to spray without protective equipment—marketing that shouldn’t be protected by federal preemption.
Beyond Roundup
The Supreme Court’s decision will likely resonate far beyond glyphosate. Several pesticide manufacturers face similar litigation in state courts based on alleged failures to warn about health risks. Syngenta is defending thousands of lawsuits from users of paraquat, a pesticide connected to Parkinson’s disease in studies of exposed populations, though regulators don’t think it causes the disease. A Supreme Court ruling that federal law overrides state lawsuits about missing warnings would provide these companies with powerful legal shields.
This decision could affect more than pesticides. The FDA regulates pharmaceuticals, medical devices, and food additives. The Consumer Product Safety Commission regulates thousands of consumer products. OSHA sets workplace exposure limits. In each case, federal agencies have decided what’s safe and set warnings or restrictions accordingly. A broad ruling could undermine whether state courts can sue manufacturers based on different scientific opinions about product safety.
The financial stakes are enormous. Bayer has already set aside roughly $16 billion to settle Roundup cases and has paid more than $11 billion in settlements and jury verdicts to date. The company faces more than 100,000 pending lawsuits related to Roundup, the vast majority of which would likely be dismissed if the Supreme Court rules in Monsanto’s favor. A preemption ruling could represent a dramatic reduction in the company’s total liability exposure. Conversely, a ruling for Durnell would preserve the state court litigation and likely generate substantial future settlements and verdicts.
The Scientific Uncertainty Underlying the Case
The legal question depends partly on how much weight one gives to competing scientific determinations. Studies on whether glyphosate causes cancer show conflicting results, and experts reasonably disagree about it. Some studies suggest associations between glyphosate exposure and non-Hodgkin’s lymphoma, particularly among agricultural workers with intensive exposure. The Agricultural Health Study found higher rates of a specific type of blood cancer in workers with the highest glyphosate exposure levels, though the overall cancer rate in exposed workers isn’t significantly elevated. Other studies find no associations.
Animal studies haven’t generally shown that glyphosate causes cancer at doses similar to what humans would experience, though the relationship between animal and human toxicity for any chemical is inherently uncertain. Scientists don’t fully understand how glyphosate could cause cancer. While the chemical does affect the nervous system and can cause cellular damage from chemical reactions under certain conditions, it’s unclear how these cellular changes would lead to cancer in people.
This situation—conflicting studies, disagreeing experts, unclear causes—is when the debate about federal law overriding state law gets most heated. If the science clearly showed glyphosate causes cancer, Monsanto’s argument would be weaker because the company would be demanding legal protection despite apparent harm. If the science clearly showed no cancer risk whatsoever, preemption would seem more justified because the company would be following well-established truth. Instead, we’re in a gray area where reasonable experts disagree about the weight of evidence and the adequacy of available research.
What Happens Next
The Supreme Court hasn’t yet scheduled oral argument, though observers expect arguments in spring 2026, with a decision likely by late June. With six conservative and three liberal justices, the outcome is difficult to predict. Conservative justices usually favor federal law overriding state law and trusting agencies, but they’ve also questioned rulings that completely prevent people from suing in state court.
Plaintiff attorneys have expressed confidence they’ll prevail, with litigation expert Brent Wisner saying that “if these conservative justices follow their past decisions, this should be an easy win for the plaintiffs” because past court decisions supposedly favored letting people sue in state court. But Wisner acknowledged his confidence assumes the Court will follow past decisions—an assumption the current Court hasn’t always followed.
The Core Tension
Monsanto v. Durnell will ask the Supreme Court to decide how much power federal agencies should have versus state courts in protecting public health. The case forces a choice between two imperfect approaches.
Completely trusting the EPA’s decisions about chemical safety would prevent state courts from challenging the EPA if it gets things wrong or favors industry, leaving citizens with no way to sue if they believe an agency got the science wrong or failed to protect adequately. Allowing people to sue in state court for products the federal government approved would defeat the purpose of having federal regulatory agencies, which is to set one national standard based on expert judgment.
The Supreme Court will decide which risk is worse: the EPA getting the science wrong, or allowing 50 different state courts to challenge federal agencies.
The Court’s decision will affect chemical regulation, farming, and what products people can buy for years. It will also show something important about how power is divided between federal and state governments—whether states can still protect their citizens’ health even when the federal government disagrees. And it will determine whether people like John Durnell, who believed they were using a product that regulators had deemed safe, have any recourse when they get sick.
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