Supreme Court to weigh in on major preemption question regarding labeling of glyphosate

Over the past several years, numerous lawsuits have been filed against the Monsanto Company regarding the safety of its herbicide Roundup and its main ingredient glyphosate. On January 16, 2026, the Supreme Court of the United States granted the Monsanto Company’s petition to review one of these cases from the Missouri Court of Appeals, Durnell v. Monsanto Company.

Background of the case

In 2019, John Durnell of St. Louis sued Monsanto in Missouri state court, arguing that exposure to glyphosate contained in Roundup caused his non-Hodgkin’s lymphoma.  Mr. Durnell argued that Monsanto should be found strictly liable for defective design of its product and for failure to warn users of the danger of using Roundup, as well as negligence. 

At trial, the jury sided with Monsanto on the defective design and negligence claims, meaning that the company was not found liable for these claims.  On the remaining claim, the 12-person jury unanimously found Monsanto to be strictly liable for its failure to warn of the risks of using glyphosate, granting Mr. Durnell $1.25 million in compensatory damages.

Eventually, Monsanto appealed the case to the Missouri Court of Appeals, claiming that the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) preempts failure to warn claims under state law. Federal preemption of state law can happen either expressly or impliedly. Express preemption happens when a federal statute contains language that specifically says that other laws or requirements cannot be imposed. Implied preemption happens when there might not be explicit language in a statute calling out the preemption, but Congress’s intent to supersede state law is implicit due to the nature of the statute.  Here, the appeals court did not find Monsanto’s preemption argument persuasive; instead finding that the language in FIFRA did not expressly preempt Mr. Durnell’s failure to warn claim, and that there was no implied irreconcilable conflict between the state and federal law. You can read the Missouri Court of Appeals opinion in its entirety here.

Since the Missouri Supreme Court declined to hear the case, Monsanto filed a petition with the Supreme Court of the United States to review the Missouri Court of Appeals’ decision on April 4, 2025. On January 16, 2026, the Supreme Court granted Monsanto’s petition, agreeing to review the case. The Court has limited its review of the case to one question: “whether the Federal Insecticide, Fungicide, and Rodenticide Act preempts a label-based failure-to-warn claim where EPA has not required the warning.”

What are each side’s arguments for the Supreme Court?

In the lead up to a Supreme Court determination to hear a case, the legal teams for both parties file documents explaining why or why not the case should be heard.  The party asking the Court to hear the case (in this case, Monsanto) files a petition for writ of certiorari, laying out their reasons for asking for review. Then the respondent (Durnell), has a chance to file a brief with the Court detailing their arguments as to why the lower court’s decision should stand.  These documents can give us some insight into how each party may form its arguments if the case is heard before the Supreme Court.

Between the two parties in this case, there are hundreds of pages laying out their lines of reasoning for hearing or not hearing the case. In its most basic form, Monsanto’s argument is that language in FIFRA expressly preempts state requirements for the labeling and packaging of herbicides like Roundup. The language they point to is in Chapter 7 of the U.S. Code, Section 136v(b) and reads: “state(s) shall not impose or continue in effect any requirements for labeling or packaging in addition to or different from those required under this subchapter.” You can see the statute here.  FIFRA requires pesticides to be registered with the federal Environmental Protection Agency (EPA) before they can be sold or distributed in the country. Monsanto asserts that because EPA continues to accept Roundup’s product registration under FIFRA without requiring the company to include any warning or caution statement about the possible health risks of glyphosate on its labeling, any state law claim that would require such a warning should be overridden.  You can read Monsanto’s petition for writ of certiorari here.

For their part, Mr. Durnell’s legal team points to a case previously decided by the Supreme Court in 2005, Bates v. Dow AgroSciences LLC (you can read that case here), in which the majority determined that state common-law claims like failure-to-warn are not automatically preempted by the language of FIFRA Section 136v(b). In Bates, the Court found that while FIFRA does preclude states from imposing different or additional labeling requirements for pesticides, it does not preclude states from imposing different or additional remedies. In other words, since “FIFRA does not provide a federal remedy to farmers and others who are injured as a result of a…violation of FIFRA’s labeling requirements, nothing in [FIFRA] precludes the states from providing such a remedy.” Furthermore, Mr. Durnell’s lawyers argue that EPA’s continued acceptance of Roundup’s product registration does not necessarily prevent the requirement of a cancer or health warning on the label, it just means that that Monsanto has not provided any evidence of glyphosate’s potential health effects or asked EPA to consider including such a warning. You can read Durnell’s response here.

What’s next?

While it can be fun to predict the outcome of Supreme Court cases, between the language of FIFRA and case law, I can’t begin to guess where the Court will end up in this case. What is certain is that the Court will examine “whether the Federal Insecticide, Fungicide, and Rodenticide Act preempts a label-based failure-to-warn claim where EPA has not required the warning.” Oral arguments for each side will happen sometime between October 2026 and April 2027, and the Court may release an opinion on the case in May or June of 2027. Additionally, the Court’s final decision will likely have implications for similar lawsuits regarding Roundup and glyphosate throughout the country. We will do our best to keep you updated on this complicated case as it works through the system. In the meantime, additional court documents and filings on the case can be found here.