In January 2019, John Durnell and 84 other plaintiffs filed a six-claim complaint in the Circuit Court of the City of St. Louis, Missouri against Monsanto Company, the manufacturer of Roundup. The complaint specifically directed claims against Monsanto for strict liability design defect, strict liability failure to warn and negligence.1 The case proceeded to trial in September 2023, and the jury returned a verdict in favor of Durnell on his strict liability failure to warn claim, awarding him $1.25 million in compensatory damages.2
Monsanto filed motions for directed verdict at the end of plaintiff’s case and at the close of their case on the basis that the claims made were expressly and impliedly preempted by federal law.3 The trial court denied both motions. Monsanto further filed a motion for judgment notwithstanding the verdict (JNOV), continuing to argue that the strict liability failure to warn claim was preempted by federal law. The trial court again denied its motion which led it to appeal to the Missouri Court of Appeals.
Monsanto’s argument concerned one point—federal law expressly and impliedly preempted the strict liability failure to warn claim against Monsanto—and the JNOV was improperly denied by the trial court.
In February 2025, the Missouri Court of Appeals affirmed the jury’s verdict. The Court of Appeals found that a strict liability failure to warn claim under Missouri law did not “impose a requirement that is ‘in addition to or different from’” the federal labeling requirements under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA),4 the act that “regulates the use, sale and labeling of pesticides.”5 As a result, the plaintiffs’ state law claim was not preempted by federal law.
Monsanto appealed to the United States Supreme Court, which granted certiorari. The court heard arguments on April 27, 2026, and issued a decision on June 25, 2026.
Supreme Court—Opinion written by Justice Kavanagh—7-2
The Supreme Court overturned the jury verdict, holding that that under FIFRA, the state law failure warn claim was preempted because “the claim would require Monsanto to add a cancer warning to Roundup’s label.”6 The court reasoned that in order to ensure labeling uniformity, the provision in FIFRA entitled “Uniformity” applied the preemption language, “State shall not impose or continue in effect any requirements for labeling or packaging in addition to or different from those required” per 7 U.S.C. §136v(b).7
FIFRA mandates that companies register pesticides with the Environmental Protection Agency (EPA) and specifically register the labeling of that product. Pursuant to §§136a(c)(5)(B) and 136(q)(1)(A), (G), EPA determines whether the label “contains all warnings ‘necessary and … adequate to protect health and the environment’ and that the label does not include any ‘false or misleading’ statements.”8
Once EPA approves a label, the company is legally required to use that label or they risk possible criminal and civil penalties should it deviate. It is only when EPA approves, requires, or amends a label change can a company deviate from that language.9
EPA’s review does not stop after the initial registration and approval of the label. Companies have a responsibility to notify EPA of “additional factual information regarding unreasonable adverse effects” of their products. §1369(a)(2). EPA, for its part, reviews any evidence or data to determine whether new labeling language should be included to alleviate “identified hazard(s).”10 The pesticide registration is reviewed by EPA every 15 years in accordance with 7 U.S.C. §136a(g)(1)(A)(iii)-(iv).
The court found that EPA has the primary authority to monitor pesticide safety and determine whether a labeling change is necessary based on scientific and environmental changes.11 EPA has undertaken a review of the components of pesticides a number of times since 1974.12 Glyphosate, an ingredient combined with other components in pesticides, such as Roundup, was first reviewed in 1974 and subsequently classified and reclassified as “unlikely to cause cancer in humans” in 1991.13 This review continued in 2017, 2019 and 2020 when glyphosate was classified as a probable carcinogen by the International Agency Research on Cancer (IARC), but EPA did not change its position that glyphosate is not carcinogenic.14 The EPA’s position is also similarly held by other international regulatory bodies.15
Accordingly, requiring Monsanto to include an additional cancer warning label would be contrary to the position that EPA holds. As such, state law that requires additional warnings not required by EPA are preempted as a matter of law. The court held that “as a matter of federal law, Monsanto legally must use a label without a cancer warning unless and until EPA approves or requires a change.”16
Possible Implications on Pesticides, PFAS, and Cosmetics/Talc
The court held that Monsanto and similarly positioned manufacturers of pesticides must only adhere to EPA labeling requirements and rely on EPA to amend when and if appropriate. This decision is likely the death knell for thousands of claims against Monsanto based on an alleged failure to warn, though future plaintiffs will likely find other bases for their claims. Perhaps because of that, Bayer, which purchased Monsanto in 2018, announced that it is still committed to go through with a multi-million dollar agreement to resolve pending litigation.17
While this decision focused on Roundup, it could have wide ranging impacts on failure to warn claims not only against other pesticides, including claims based on PFAS in pesticides, but any product where labels are regulated by the federal government. The Food and Drug Administration (FDA), like EPA, is responsible for reviewing scientific data and monitoring the safety of products such as talc and cosmetics to protect public health.18 Cosmetic warning labels, in accordance with the Federal Food, Drug and Cosmetic Act (FD&C) and Fair Packaging and Labeling (FP&L), do not require pre-market approval, but rather they must adhere to language to avoid being “misbranded.”19 Labels for talc products, like cosmetics, do not have to undergo FDA review and approval, but must adhere to labeling requirements outlined in the FD&C.20 Expect manufacturers of these products to test whether Durnell also preempts failure to warn claims against these types of products.
MG+M Law Clerk Christine Drew is a contributing author of this article.
1 Missouri Court of Appeals Decision: No. ED112410: https://www.courts.mo.gov/file/ED/Opinion_ED112410.pdf
2 Id.
3 Id.
4 Id.
5 Id. at 3-4
6 https://www.supremecourt.gov/opinions/25pdf/24-1068_n7ip.pdf
7 609 US ___ (2026), 9
8 Id. at 10; See also 7 U.S.C §136.
9 Id.
10 Id. at 5; See also 40 CFR §152.170(e)(1)
11 Id. at 6
12 Id.
13 Id. at 7
14 Id.
15 Id.
16 Id.
17 https://apnews.com/article/supreme-court-roundup-monsanto-a7f054d80919f98bdfc5190013a8f6f1
18 https://www.fda.gov/cosmetics/cosmetic-ingredients/and-polyfluoroalkyl-substances-pfas-cosmetics
19 https://www.fda.gov/cosmetics/cosmetics-labeling-regulations/cosmetics-labeling-guide#clgh
