On June 25, 2026, the Supreme Court issued its highly anticipated in ruling in the landmark case, Monsanto Co. v. Durnell, No. 21-1068 (2026), a lawsuit that asked whether federal pesticide law preempts state law tort claims. Specifically, the Court was asked to determine whether the Federal Insecticide, Fungicide, and Rodenticide Act (“FIFRA”) preempts state law failure to warn claims. In a 7-2 ruling, the Supreme Court held that FIFRA expressly preempts such claims. The decision sets a new precedent that will impact pesticide litigation and regulation going forward.
Background
The Supreme Court’s decision stems from over a decade of litigation centered on the most widely used herbicide in the United States – Roundup. First developed in the 1970s, Roundup has been available for decades as both an agricultural pesticide and for landscape and residential use.
Glyphosate, the active ingredient in Roundup, was first approved by the Environmental Protection Agency (“EPA”) under FIFRA in 1974. At the time, and in every review of the chemical EPA has done` since, the agency concluded that glyphosate was not carcinogenic in humans. However, in 2015, the International Agency for Research on Cancer issued a report concluding that glyphosate was “probably carcinogenic to humans.” In the decade since, tens of thousands of lawsuits have been filed against Monsanto (owned by the Bayer Corporation) by plaintiffs who allege that exposure to the glyphosate in Roundup caused them to develop non-Hodgkin’s lymphoma and that Bayer failed to warn them about the risk.
Roundup liability lawsuits are typically filed in state courts and raise products liability claims that are based in state law, including the claim of failure to warn. Over the years, Bayer has consistently argued that the plaintiffs’ claims of failure to warn is preempted by FIFRA and should not be raised in court. Preemption is a legal doctrine which refers to the idea that law passed by a “higher” government will supersede law passed by a “lower” government if the two laws conflict. If a federal law and a state law conflict, the doctrine of preemption means that the federal law will supersede or preempt the state law. Sometimes preemption is obvious because Congress expressly states that it intends for a federal statute to preempt state law. Other times, preemption might occur because it is impossible to comply with both federal and state law at the same time. More information on preemption is available here.
Failure to warn is a civil tort often raised in products liability lawsuits. Like most civil torts, failure to warn is based in state law and enforced at a state level. A plaintiff will raise a failure to warn claim to argue that a product’s manufacturer failed to provide adequate warnings or instructions as to the safe use of a product and that failure directly resulted in the plaintiff suffering an injury. In Roundup liability lawsuits, plaintiffs raise failure to warn to claim that Bayer had a duty to warn consumers about the potential health risks of using its products but failed to do so.
Bayer has argued that FIFRA preempts state law failure to warn claims. FIFRA is the primary federal statute regulating pesticides in the United States. It is administered by EPA and no pesticide may be sold or distributed in the United States until EPA has registered the product under FIFRA. To register a pesticide, EPA must determine that the product will not cause “unreasonable adverse effects” on the environment when used as intended. 7 U.S.C. § 136a(c)(5)(C). FIFRA defines “unreasonable adverse effects” as “any unreasonable risk to man or the environment, taking into account the economic, social, and environmental costs and benefits of the use of any pesticide[.]” 7 U.S.C. § 136(bb). To meet this standard, EPA will review data submitted by the manufacturer seeking to register a product and perform a human health analysis that, among other things, assesses the potential carcinogenicity of a pesticide or its active ingredient. If EPA concludes that a pesticide satisfies FIFRA standards, it will register the pesticide and approve a final label for the product.
A registered pesticide label is an important document. It contains a variety of information including the product ingredients, how to use the product, and any health and safety warnings that EPA requires the product to bear. FIFRA regulates these labels strictly. In a provision titled “Uniformity,” FIFRA clarifies that states may not “impose or continue in effect any requirements for labeling or packaging in addition to or different from those required under [FIFRA].” 7 U.S.C. § 136v(b). FIFRA also prohibits the sale of distribution of any pesticide that is “misbranded.” 7 U.S.C. § 136j(a)(1)(E). The statutory definition of “misbranded” is extensive. A pesticide may be misbranded if its labeling bears any false statement, does not include the product’s registration number, does not list the product’s ingredients, or if the label omits a “warning or caution statement that maybe be necessary and […] adequate to protect health[.]” 7 U.S.C. § 136(q).
In Monsanto Co. v. Durnell, Bayer argued that FIFRA preempts Durnell’s failure to warn claim because FIFRA prohibits states from adding any requirements for pesticide labeling or packing that are “in addition to or different from” those required under FIFRA. Bayer argues that because EPA has never required a cancer warning to be included on the labeling for Roundup, then a state may not add a cancer warning to the label. Because the only way to fully satisfy Durnell’s failure to warn claim would be to add a cancer warning to the Roundup label, Bayer argues that FIFRA has preempted the claim.
In response, Durnell argues that FIFRA does not preempt the failure to warn claim because the claim is “parallel” to FIFRA’s prohibition on misbranding. Durnell has based this argument on the 2005 Supreme Court decision, Bates v. Dow Agrosciences LLC, 544 U.S. 431 where the Court ruled that a failure to warn claim against a pesticide manufacturer could proceed if the claim was “parallel” to FIFRA’s misbranding provisions. The claim would be considered “parallel” if a violation of the state law would amount to a violation of FIFRA. For a more detailed breakdown of the arguments raised in Monsanto Co. v. Durnell, click here.
To date, three other federal courts have considered this argument. Two courts, the Ninth and Eleventh Circuit Courts of Appeals, ruled that FIFRA does not preempt state law failure to warn claims while the Third Circuit Court of Appeals ruled in 2023 that FIFRA does preempt such claims. This split between the circuits ultimately prompted the Supreme Court to take up Monsanto Co. v. Durnell in order to resolve the matter.
The Court’s Decision
In a 7-2 opinion, the Supreme Court concluded that FIFRA preempts state law claims of failure to warn. According to the majority opinion, authored by Justice Kavanaugh, the text of FIFRA together with its implementing regulations expressly preempt state law claims of failure to warn.
The Court began its opinion by reviewing the relevant provisions of FIFRA and its regulations. First, the Court examined the Uniformity provision of FIFRA which provides that a state may not “impose or continue in effect any requirements for labeling or packing in addition to or different from those required under [FIFRA].” 7 U.S.C. § 136v(b). According to the Court, this language means that FIFRA preempts any state law labeling requirement that differs from the federal labeling requirements imposed under FIFRA. The Court then considered whether state tort duties such as though imposed by a failure to warn claim would be considered state labeling requirements. According to the Court, failure to warn claims like the one raised by Durnell do qualify as labeling requirements because those rules “set a standard for a product’s labeling.” Next, the Court considered whether Durnell’s failure to warn claim, which the Court notes would require a cancer warning to be included on the Roundup label, would impose a labeling requirement that is “in addition to or different from” federal labeling requirements imposed under FIFRA. The Court concluded that the claim would impose a different requirement from those required under FIFRA because EPA has never required the Roundup label to include a cancer warning.
The majority opinion explains that to register a pesticide, EPA must approve the pesticide’s label. To approve a label, EPA must determine that the product is not misbranded and that the label therefore includes any warnings “necessary and […] adequate to protect health and the environment” and does not include any “false or misleading” statements. 7 U.S.C. §§ 136a(c)(5)(B); 136(q)(1)(A), (G). After EPA approves a pesticide’s label, manufacturers are then required to use that label “unless and until” EPA approves or requires a label change. 7 U.S.C. § 136a(f)(1); 40 C.F.R. § 152.44(a). Reviewing this, the Court concludes that FIFRA requires Bayer to sell Roundup with the label that EPA approved when registering the product. Because that label does not include a cancer warning, Durnell’s state law failure to warn claim would add a requirement to the Roundup label that is “in addition to” and “different from” Bayer’s federal law labeling obligations and is therefore preempted by FIFRA.
After reaching this conclusion, the majority noted that its reasoning was supported by Supreme Court precedent. In Bates v. Dow Agrosciences, a group of plaintiffs sued Dow over its pesticide Strongarm, raising failure to warn claims to argue that the Dow had mislead consumers by claiming that Strongarm was effective for peanut crops grown in all soil conditions when in reality the product stunted peanut growth in certain soils. There, the Court allowed the failure to warn claim to proceed, concluding that the plaintiff’s claim was “parallel” to a claim of misbranding. The Court in Bates explained that a failure to warn claim would be preempted by FIFRA if would conflict with any relevant labeling “requirements” under FIFRA, including FIFRA’s misbranding provision and any EPA regulations that “give content” to FIFRA’s misbranding standards. As an example, the Bates Court provided that if an EPA regulation required the word “CAUTION” to appear on a particular pesticide label, a state law failure to warn claim that targeted the pesticide label for stating “CAUTION” instead of “DANGER” would be preempted by FIFRA because it would require the label to bear language different from what the federal statute required.
The majority in Monsanto Co. v. Durnell explained that just like an EPA regulation requiring a pesticide label to bear the word “CAUTION” rather than “DANGER,” EPA’s registration determination that the Roundup label not include a cancer warning qualifies as a federal labeling requirement that cannot be altered by state law. The plaintiffs in Bates brought failure to warn claims to raise concerns over the efficacy of Strongarm, something that EPA did not review when registering the pesticide. Durnell, on the other hand, brought failure to warn claims to raise concerns over the safety of Roundup. According to the Court, not only does EPA consider the safety of a pesticide when registering the product, but EPA’s final registration decision reflects the agency’s “considered judgement” that a pesticide label contains all necessary safety warnings. Therefore, the Court concludes that Monsanto Co. v. Durnell is in line with Bates v. Dow Agrosciences because when to come to safety claims, EPA’s final registration decisions are considered labeling requirements that preempt any state requirements that are “in addition to” or “different from” those required under FIFRA.
Dissent
Although a majority of the Justices concluded that FIFRA preempts state law failure to warn claims, two Justices dissented. Justice Jackson, joined by Justice Gorsuch, argue that Durnell’s failure to warn claims should not be preempted by FIFRA because the claims are “parallel” to FIFRA’s misbranding provisions. According to the dissent, FIFRA’s Uniformity provision “limits” but does not “eliminate” state authority over pesticide labeling language. Instead, the dissent claims that state labeling requirements that are “equivalent to” FIFRA requirements should not be preempted.
The majority concludes that a pesticide label approved by EPA constitutes a requirement under FIFRA, at least as far as safety claims are concerned. However, the dissent disagrees, concluding instead that a registered pesticide label reflects only EPA’s “best judgment” that the label satisfies FIFRA. Where FIFRA provides that states may not impose labeling requirements that are “in addition to” or “different from” those “required under” FIFRA, the dissent views the prohibition on misbranding as the requirement being referred to, not the EPA-approved label. From there, the dissent reasons that if an additional warning is necessary to bring a pesticide label into full compliance with FIFRA’s requirement that a pesticide not be misbranded, then a state law duty could require that warning. For that reason, the dissent would not conclude that FIFRA preempts Durnell’s failure to warn claim.
Going Forward
The Supreme Court’s conclusion in Monsanto Co. v. Durnell that FIFRA preempts state law failure to warn claims will have immediate impacts on thousands of on-going Roundup liability lawsuits. Plaintiffs in these cases will no longer be able to advance their claims of failure to warn. Instead, Roundup liability plaintiffs may decide to seek success on other claims besides failure to warn or may attempt to resolve their cases through a settlement agreement. Earlier this year, a state court in Missouri granted preliminary approval to a proposed settlement agreement from Bayer that would provide around $7 billion to settle current and possibly future Roundup liability lawsuits. Plaintiffs that do not settle may attempt to proceed relying on other claims, such as design defect or negligence. They may also petition EPA to modify the Roundup label, something the Supreme Court notes anyone may do.
Beyond the present Roundup liability lawsuits, the Court’s ruling in Monsanto Co. v. Durnell will impact pesticide liability litigation more generally. Lawsuits claiming that a pesticide manufacturer failed to warn consumers about safety risks have been raised to challenge additional pesticides in recent years, including chlorpyrifos and paraquat. With those claims no longer available, consumers who question the safety claims included on a pesticide label may pursue avenues other than product liability lawsuits to have their concerns heard.
The Court’s decision clarifies the scope of FIFRA’s Uniformity provision. When EPA approves a pesticide label for registration, states may not add safety warnings to the label that are “in addition to” or “different from” what EPA has approved.
To read the Supreme Court’s decision in Monsanto Co. v. Durnell, click here.
To read the Supreme Court’s decision in Bates v. Dow Agrosciences, click here.
To read the text of FIFRA, click here.
For more information on pesticides from the National Agricultural Law Center, click here.