Monsanto Company v. Durnell

    Issues

    Does the Federal Insecticide, Fungicide, and Rodenticide Act bar a failure-to-warn claim based on labeling when the EPA has not mandated the warning?

    Oral argument:
    April 27, 2026
    Court below:
    Missouri Court of Appeals Eastern District

    This case asks whether the Federal Insecticide, Fungicide, and Rodenticide Act (“FIFRA”) bars a lawsuit alleging that a product failed to provide adequate warnings or instructions when the Environmental Protection Agency (“EPA”) has not required such warnings. Petitioner Monsanto Company argues that Respondent John L. Durnell’s claim is preempted by FIFRA, which bars changes to a product label following approval by the EPA, as well as by the impossibility of compliance with both state and federal law. Durnell argues that Missouri law and FIFRA are equivalent laws, and that Missouri law imposes no additional labeling requirements for pesticides. The outcome of this case carries significant policy implications for federalism and regulatory authority. The case may also have an impact on nationwide agricultural and economic interests.

    Questions as Framed for the Court by the Parties

    Whether the Federal Insecticide, Fungicide, and Rodenticide Act preempts a label-based failure-to-warn claim where EPA has not required the warning.

    Facts

    In January 2019, Respondent John L. Durnell sued Petitioner Monsanto Company (“Monsanto”) in Missouri state court under claims of strict liability for failure to warn, defective design, and negligence. Durnell alleged that glyphosate, an ingredient in the pesticide Roundup, which is manufactured by Monsanto, had caused him to develop lymphoma through his regular use of Roundup. Missouri law imposes strict liability on manufacturers if a company fails to give “adequate warning of the danger,” regardless of the company’s knowledge of the risk.

    In the Circuit Court of the City of St. Louis, the state trial court, Monsanto moved for a directed verdict, arguing that Durnell’s claims of strict liability and failure to warn were preempted by the Federal Insecticide, Fungicide, and Rodenticide Act (“FIFRA”). FIFRA is the federal statutory scheme that “regulates the use, sale, and labeling of pesticides.” Under 7 U.S.C. § 136v, FIFRA clarifies that states “may regulate the sale or use of any federally registered pesticide” provided that state laws do not impose “requirements for labeling or packaging in addition to or different from those required under” FIFRA. Monsanto argued that preemption was both express, since the statute explicitly prohibits additional labeling requirements imposed by states, and implied, because state and federal law conflicted with one another. Because FIFRA forbids states from mandating additional labeling standards, requiring that all claims labeled on pesticides need to be approved by the Environmental Protection Agency (“EPA”), Monsanto argued that it would be impossible to comply with both Missouri tort law and federal regulations. The trial court denied Monsanto’s motion and the jury found in favor of Durnell on his “failure-to-warn” claim, awarding Durnell $1.25 million in damages. Monsanto filed for either a judgement notwithstanding the verdict (“JNOV”) or a new trial, both of which the state trial court denied, ruling the same way as the jury.

    Monsanto appealed this decision to the Missouri Court of Appeals Eastern District and requested a reversal, arguing that the trial court erred in denying Monsanto a JNOV, as federal law preempted Durnell’s claim of “failure to warn.” In order to meet this requirement, Monsanto would be required to prove that Monsanto “fully informed” the EPA of the justifications for a cancer warning that would have been required by Missouri law, that the EPA informed Monsanto that it denied approval of the new warning label, and that the EPA denied the warning label “pursuant to authority that carries the force of law.” The Missouri Court of Appeals ruled against Monsanto, stating that Monsanto did not meet the first two requirements. According to the court, Monsanto’s claim that the EPA would not approve a new label was not sufficient to show an “irreconcilable conflict” between state and federal law. The EPA’s prior approval of Roundup labels without the cancer warning for glyphosate, along with the EPA’s finding that glyphosate was “not likely to be carcinogenic to humans,” did not mean the EPA was certain to reject future labels with a cancer warning. The Missouri Court of Appeals affirmed the trial court’s verdict, also ruling that Monsanto's JNOV motion was correctly denied.

    On April 4, 2025, Monsanto petitioned the Supreme Court of the United States to hear this case. The Supreme Court granted certiorari on January 16, 2026.

    Analysis

    EXPRESS PREEMPTION

    Monsanto argues that Durnell’s “failure-to-warn” claim is expressly preempted by the text of FIFRA, which explicitly forbids companies from altering pesticide labels to comply with state laws if states require labeling “in addition to or different from” what is imposed by federal law. Since Missouri tort law would require a cancer warning to be added to Roundup’s product label, Monsanto claims it would have had to alter a label already approved by the EPA in order to comply, an action explicitly disallowed by FIFRA. Monsanto points out that FIFRA requires pesticide manufacturers to receive specific approval from the EPA to modify a product’s labeling or packaging, and that manufacturers cannot alter a label after the EPA has approved it, even if the manufacturer learns of additional “unreasonable adverse effects.” Instead, Monsanto explains that FIFRA requires a manufacturer to submit proposed label changes to the EPA, which will then consider the label’s impact on consumers and the economy before approving a new warning. Furthermore, Monsanto argues that the EPA conducts rigorous testing of carcinogens, and that the EPA’s approval and registration of a specific pesticide represents a determination by the agency that the pesticide is safe when used according to its label. Monsanto cites Bates v. Dow Agrosciences, in which the Supreme Court ruled that FIFRA defines additional “requirements” for labeling to include not only “statutes and regulations,” but “any rule of law that must be obeyed.” Because the EPA’s approval of Roundup’s label is a determination by the agency, Monsanto insists it is equivalent to a “rule of law that must be obeyed,” and therefore the text of FIFRA preempts Missouri’s statute in the same way that federal rules and regulations would.

    In contrast, Durnell argues that the text of FIFRA does not explicitly preempt a “failure-to-warn” claim because Missouri tort law does not impose any requirements “in addition to or different from” FIFRA. Durnell points out that Missouri law establishes the same legal standard as and uses similar language to FIFRA, given that both Missouri law and FIFRA require product labels to contain “adequate” warnings that are not “false or misleading.” Durnell points out that both federal and state law allow courts to make the actual determination of whether a specific pesticide label’s claims are misleading, not the EPA. Durnell furthers that the Circuit Court of the City of St. Louis and its jury were free to decide that Roundup’s lack of a cancer warning constituted “mislabeling” through their interpretation of existing requirements for labels, and that the Circuit Court was not imposing an entirely new requirement through its decision to find Monsanto liable for failure-to-warn. Even if Missouri tort law differed from FIFRA requirements, Durnell explains that according to the Supreme Court in Bates, FIFRA only preempts state law that “actually conflicts” with federal law. Durnell asserts that Monsanto lost the opportunity to make this argument by failing to request a limiting instruction advising the jury to only consider liability under federal law. Durnell explains that Bates, a case heavily relied upon by Monsanto, placed the burden upon Monsanto itself to prove that there was a conflict by explaining FIFRA’s standards for misbranding. Durnell points out that Monsanto never requested this jury instruction, but rather approved the instructions given to the jury at the trial court and did not challenge them at any point in the appeals process.

    IMPLIED PREEMPTION

    Monsanto argues that, in addition to the express preemption within FIFRA’s text, Durnell’s claim is also preempted by the “impossibility” of compliance with both federal labeling requirements and Missouri tort law, also known as implied preemption. Monsanto asserts that the test for such a conflict is whether the company would have been able to “independently do under federal law what state law requires of it.” Monsanto claims that it could not have independently changed its product label to include the cancer warning required by Missouri state law, as FIFRA prohibits manufacturers from selling a pesticide with a label making “substantially different” claims than those already approved by the EPA. To support this assertion, Monsanto cites PLIVA, Inc. v. Mensing, in which the Supreme Court found that “failure-to-warn” claims against a drug manufacturer were preempted by federal law because the FDA requires generic drug label warnings to be identical to their brand-name counterparts. Although Monsanto could have submitted a label containing a cancer warning to the EPA for approval, Monsanto emphasizes that the test established in PLIVA was whether a company could take unilateral action to comply with state law requirements, without “special permission and assistance” from the federal government. Monsanto argues that because it needed the EPA’s approval to add a cancer warning, it would have met the test of impossibility established by PLIVA. Monsanto contends that although the Missouri Court of Appeals distinguished PLIVA because that case involved interpreting a different statute than FIFRA, the principle of PLIVA’s ruling still applied, as it related to the broader issue of conflicting state and federal laws rather than the interpretation of a specific statute. Additionally, even if it had submitted a labeling change to the EPA, Monsanto predicts that the agency would have vetoed such a change since it had already approved labels without cancer warnings for products containing glyphosate for decades.

    Durnell counters that his “failure-to-warn” claim is not impliedly preempted by FIFRA because the statute does allow companies to make independent changes to labels. Durnell concedes that FIFRA forbids companies from using labels with “claims” distinct from those already approved. However, Durnell makes a distinction between “claims” and “warnings,” pointing out that an application for pesticide registration with the EPA requires a copy of the product’s label, all claims made for the pesticide, and “directions for its use” as distinct categories. Durnell posits that companies can still modify labeling and directions for use, as FIFRA only requires that Monsanto’s claims remain unaltered and does not otherwise restrict changes to a product’s label. Furthermore, Durnell contends that FIFRA’s misbranding requirement required Monsanto to either change its label to include a cancer warning, stop selling Roundup, or face the legal consequences of its misbranding.Durnell argues that because both Missouri tort law and federal law both require a company to “stop selling” a mislabeled pesticide, the steps required by state and federal law are functionally equivalent. Thus, according to Durnell, Missouri does not require Monsanto to change its label or impose any requirements “in addition to or different from” those of FIFRA. Additionally, Durnell challenges Monsanto’s claim that the EPA would have vetoed a label for Roundup that contained a cancer warning, arguing that a manufacturer must provide “clear evidence” that the agency would not approve an additional warning in order to establish preemption. Durnell points out that Monsanto erroneously assumed that its warning would have been rejected by the EPA, as Monsanto never provided “clear evidence” that a cancer warning for Roundup was ever actually rejected by, or even submitted to, the EPA.

    Discussion

    FEDERAL ENFORCEMENT AND STATE RIGHTS 

    The Chamber of Commerce of the U.S. and additional parties (“Chamber”), in support of Monsanto, assert that allowing state law failure-to-warn claims would undermine Congress’s aim of creating national uniformity in pesticide labeling via FIFRA. The Chamber adds that without uniform pesticide labeling, businesses would be subject to inconsistent liability across at least fifty jurisdictions. If local jurisdictions add their own labeling requirements too, the Chamber warns that businesses would be subject to thousands of inconsistent and “unworkable” mandates. Furthermore, the Atlantic Legal Foundation, in support of Monsanto, argues that the EPA is granted sole authority to set label content and issue safety warnings to create national uniformity in pesticide labeling that is rooted in scientific evidence. The American Tort Reform Association and other organizations in support of Monsanto, agree, asserting that the EPA’s scientifically rigorous, comprehensive, and risk-based evaluations of agricultural substances support its exclusive authority over pesticide labeling.

    New Mexico and seventeen other states, in support of Durnell, counter that EPA labeling regulations would not actually offer uniformity, as the regulations would fluctuate with changes in administration. Furthermore,Farmworker Justice and other organizations (“Farmworker Advocates”), in support of Durnell, contend that FIFRA’s framework includes “cooperative federalism,” in which states may impose stricter limits than federal regulations without being at risk of violating federal law. Farmworker Advocates emphasize the need for state and jury oversight to protect public health, arguing that EPA regulations overlook cancer risks by ignoring inert ingredients, resulting in inadequate labels. Additionally, thirty-six state legislators (“thirty-six legislators”), in support of Durnell, argue that individual states bear primary responsibility for addressing public policy issues involving health, safety, and welfare, not the federal government. The thirty-six legislators assert that the Framers intended state governments to bear primary responsibility for these policy issues because their proximity to the public makes them better suited to innovate and respond to local needs.

    AGRICULTURAL AND ECONOMIC IMPACTS

    In support of Monsanto, the Chamber argues that a lack of uniform pesticide labeling would create inefficiencies, raise prices, hinder competition, and harm consumers. The Chamber warns that economic harm would extend to medical devices, cosmetics, and food industries, as FIFRA shares similar clauses with federal statutes that regulate those industries. Additionally, in support of Monsanto, National Agricultural Associations (“NAA”) argue that nonuniform labeling would increase liability and force “EPA-registered pesticide products” like glyphosate, which are essential for protecting crops, off the market. As a result, the NAA explains, the U.S. would rely more on imports from China and India, potentially leading to reduced crop yields and elevated food prices. Missouri State Senator Jason Bean and other parties agree, asserting that foreign manufacturers gain an advantage by avoiding the “tort tax,” which consists of costs from compliance, litigation, and large damages awards in U.S. courts.

    In support of Durnell, Centro de los Derechos del Migrante and other parties (“Farmer and Farmworker Groups”), counter that requiring adequate warning labels to users of glyphosate would not create the “food-supply calamity” asserted by Monsanto and its amici. TheFarmer and Farmworker Groups highlight that even if requiring compliance with state and federal labeling schemes prevented Monsanto from selling glyphosate, farmers would not actually lose access to the pesticide, as Monsanto’s amici have already admitted that producers in other countries supply generic versions. Furthermore, the Farmer and Farmworker Groups note that farmers can successfully control weeds and maintain crop yields with other pesticides that are “statistically as effective” as glyphosate and farming techniques that do not require pesticides. The Farmer and Farmworker Groups explain that reliance on glyphosate actually undermines the long-term stability of agriculture by causing crop damage through drift, harming organic farming, threatening the environment, and reducing yields, as well as endangering farmers and farmworkers by increasing exposure to harmful chemicals.

    Conclusion

    Authors

    Written by:Brenda Narvaez and Ria Panchal

    Edited by:Zac Jacobson

    Additional Resources