Durnell Environmental Lawsuit Against Monsanto: Supreme Court Case

The Durnell lawsuit against Monsanto is a Roundup cancer case now before the U.S. Supreme Court, brought by St. Louis resident John Durnell, who won a $1.25 million jury verdict after developing non-Hodgkin’s lymphoma following more than two decades of spraying the weedkiller. The Court’s ruling will decide whether federal pesticide law prevents users like Durnell from suing Monsanto for failing to warn about cancer risks, and it could reshape roughly 65,000 pending Roundup claims across the country.

Who John Durnell Is

Starting in 1996, Durnell served as the “spray guy” for a neighborhood association in the Soulard area of St. Louis, spending hours each week during growing months using Roundup to clear weeds from local parks. He wore no gloves, mask, or goggles, because Monsanto’s labeling and marketing suggested the product was safe enough to apply in a t-shirt and shorts.¹

In 2018, he was diagnosed with mantle cell lymphoma, a form of non-Hodgkin’s lymphoma. Chemotherapy caused significant weight loss and lasting damage to his legs, ending the volunteer work that had defined his community life. He remains married to his partner of five decades, Richard, and was in remission as of the most recent filings.¹

In January 2019, Durnell sued Monsanto in Missouri state court on claims of defective design, negligence, and failure to warn. He argued Monsanto should have warned users about glyphosate’s potential cancer risks, particularly after the International Agency for Research on Cancer classified the chemical as “probably carcinogenic to humans” in 2015.²

The Verdict and the Path to the Supreme Court

A jury in the Circuit Court of the City of St. Louis tried the case in September 2023. It found for Durnell on his strict liability failure-to-warn claim and awarded $1.25 million in compensatory damages. Monsanto prevailed on the defective design and negligence claims.³

Monsanto argued after trial that the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), the federal statute governing pesticide registration and labeling, preempted the failure-to-warn claim. The trial court disagreed, and on February 11, 2025, the Missouri Court of Appeals for the Eastern District affirmed. The Missouri Supreme Court declined review, and Monsanto petitioned the U.S. Supreme Court, which granted certiorari on January 16, 2026.⁴⁵

The Question the Justices Agreed to Decide

The Court is considering a single question: whether FIFRA preempts a label-based failure-to-warn claim where the EPA has not required the warning.⁵

The dispute turns on Section 136v(b) of FIFRA, which says states “shall not impose or continue in effect any requirements for labeling or packaging in addition to or different from those required” under federal law.⁶ The question is whether a jury verdict punishing Monsanto for not warning about cancer effectively imposes a labeling “requirement” different from the EPA-approved label, which contains no such warning.

Monsanto’s Position

Monsanto argues that because the EPA registered Roundup without a cancer warning and has historically concluded that glyphosate does not pose a cancer risk to humans, any state-level demand for such a warning is preempted. The company says it cannot unilaterally change its EPA-approved label, and that fifty states imposing different labeling demands through tort suits would gut the uniform national standard Congress intended.⁷

Durnell’s Position

Durnell relies on the Supreme Court’s 2005 decision in Bates v. Dow Agrosciences, which held that FIFRA does not preempt state-law claims “equivalent to, and fully consistent with” the statute’s own misbranding provisions.⁸ FIFRA itself prohibits “misbranded” products, including those with inadequate warnings, and Durnell says his state-law claim enforces that same standard. He also points out that FIFRA explicitly says EPA registration “shall not be construed as a defense” to violations of the Act, meaning a product can be registered and inadequately labeled at the same time.⁹

He also contests the strength of the EPA’s cancer determination. In 2022, the Ninth Circuit vacated the human-health portion of the EPA’s glyphosate review, finding the agency’s “not likely to be carcinogenic” conclusion was not supported by substantial evidence and was internally inconsistent with the agency’s own acknowledgment that it could not determine whether glyphosate exposure was associated with non-Hodgkin’s lymphoma.¹⁰

Why the Case Reached the Supreme Court

Lower courts have split cleanly on the same question. In August 2024, the Third Circuit ruled in Schaffner v. Monsanto that FIFRA expressly preempts state failure-to-warn claims about Roundup, reasoning that any state law requiring a cancer warning would be “in addition to or different from” the EPA-approved label.¹¹ The Missouri Court of Appeals in Durnell reached the opposite result, as did the Ninth Circuit in Hardeman v. Monsanto, the Eleventh Circuit in Carson v. Monsanto, and state courts in California and Oregon.¹²

What Happened at Oral Argument

The Court heard roughly 75 minutes of argument on April 27, 2026. Paul Clement argued for Monsanto, Ashley Keller for Durnell, and Principal Deputy Solicitor General Sarah Harris for the United States, which supported Monsanto and warned of a “State-by-State cacophony” if state suits proceed.¹³⁷

Several justices pushed back on Monsanto. Justice Ketanji Brown Jackson noted that the EPA may go fifteen years between pesticide registration reviews and asked why states cannot fill that gap when new safety research emerges. Chief Justice John Roberts questioned why states cannot “call danger to the attention of the people” while the EPA completes its own review. Justice Neil Gorsuch pointed to what he framed as a logical problem: federal policy allows states the greater power of banning a product outright while denying the lesser power of requiring a label change.⁷

Others focused on uniformity. Justice Elena Kagan asked how state-level suits square with FIFRA’s uniformity provision, and Justice Brett Kavanaugh questioned how uniformity survives if “each state can require different things.” Durnell’s lawyer faced fewer questions than either Clement or Harris, making the justices’ leanings hard to read.⁷

The Larger Roundup Picture

Bayer, which acquired Monsanto in 2018, faces roughly 65,000 outstanding U.S. claims from people alleging Roundup caused their non-Hodgkin’s lymphoma, and has already paid more than $11 billion in prior settlements and verdicts.¹⁴

On February 17, 2026, Bayer announced a proposed $7.25 billion class-action settlement covering current and future claims. The deal reaches occupational and residential Roundup users diagnosed with non-Hodgkin’s lymphoma, with tiered compensation ranging from roughly $10,000 to $165,000 depending on exposure, age at diagnosis, and type of lymphoma.¹⁵ A Missouri state court judge granted preliminary approval in March 2026, with a final fairness hearing expected in early July. The opt-out deadline passed on June 4, 2026, though dozens filed formal objections.¹⁶

On February 18, 2026, President Donald Trump signed an executive order invoking the Defense Production Act to declare domestic production of glyphosate-based herbicides critical to national security. The order directs the Secretary of Agriculture to prioritize production and confers legal immunity on producers following federal directives.¹⁷ Representatives Thomas Massie and Chellie Pingree introduced the “No Immunity for Glyphosate Act” in response, aiming to prevent the order from functioning as a liability shield.¹⁴

What a Ruling Could Mean

A decision for Monsanto would establish that FIFRA preempts state failure-to-warn claims when the EPA has not required the specific warning at issue. That would likely foreclose many of the tens of thousands of pending Roundup lawsuits and could insulate pesticide manufacturers from state tort liability more broadly.⁹ Because FIFRA provides no private right of action for people harmed by pesticides, such a ruling would leave injured plaintiffs without a federal or state avenue for compensation, an outcome amici on Durnell’s side have called “complete remedial foreclosure.”¹⁸

A decision for Durnell would preserve the ability of state courts and juries to hold manufacturers accountable for inadequate warnings even where the EPA has not mandated one. It would keep the legal framework driving Roundup litigation intact and could affect Bayer’s calculus on the $7.25 billion settlement.

As of mid-2026, the Court has not issued its decision. A ruling is expected by early July 2026.⁷

1
U.S. Supreme Court. Durnell v. Monsanto Company, Brief in Opposition Appendix
2
SCOTUSblog. Justices To Consider Relationship Between Federal and State Rules for Cancer Warnings on Pesticides
3
Oyez. Monsanto Company v. Durnell
4
McGuireWoods. State Court Rejection of Federal Preemption in Product Liability Claim Highlights Uncertainty for Manufacturers
5
U.S. Supreme Court. Monsanto Company v. Durnell, Docket No. 24-1068
6
U.S. EPA. Federal Insecticide, Fungicide, and Rodenticide Act and Federal Facilities
7
SCOTUSblog. Justices Debate Who Gets To Decide That Pesticide Labels Need a Cancer Warning
8
Oyez. Bates v. Dow Agrosciences LLC
9
Earthjustice. SCOTUS Oral Argument, Monsanto v. Durnell
10
National Agricultural Law Center. Ninth Circuit Orders EPA To Revisit Conclusion That Glyphosate Is Not Likely To Cause Cancer
11
U.S. Court of Appeals for the Third Circuit. Schaffner v. Monsanto Corporation
12
Harvard Law Review. Preempting Toxic Torts: Third Circuit Opens Split on Cancer Warnings in Schaffner v. Monsanto
13
SCOTUSblog. Monsanto Company v. Durnell
14
Chemical & Engineering News. Glyphosate, Roundup, Bayer, Monsanto, Preemption, Trump Executive Order
15
The New Lede. Bayer Proposes $7.25 Billion Roundup Settlement
16
Reuters. Federal Judge Sends Bayer’s $7.25 Billion Roundup Settlement Back to Missouri State Court
17
The White House. Promoting the National Defense by Ensuring an Adequate Supply of Elemental Phosphorus and Glyphosate-Based Herbicides
18
U.S. Supreme Court. Stand for Health Freedom Amicus Brief, Monsanto v. Durnell