The U.S. Supreme Court is set to hear arguments in a closely watched case that could reshape pesticide regulation, corporate liability, and thousands of ongoing lawsuits across the country. At the center of the dispute in Monsanto Company v. Durnell is a technical but consequential legal question: whether federal law governing pesticide labels overrides state-level requirements.
The case revolves around Monsanto and its widely used weed killer Roundup, which contains the active ingredient glyphosate. Since the 1970s, glyphosate-based products have been regulated under the Federal Insecticide, Fungicide, and Rodenticide Act, commonly known as FIFRA. The Environmental Protection Agency has repeatedly reviewed glyphosate and has concluded that it does not pose a cancer risk to humans when used as directed, though that claim is widely disputed throughout the scientific community.
In 2015, the International Agency for Research on Cancer, part of the World Health Organization, classified glyphosate as “probably carcinogenic to humans.” That finding triggered a wave of lawsuits from individuals who claimed that exposure to Roundup caused cancers such as non-Hodgkin’s lymphoma.
One of those plaintiffs, John Durnell, sued Monsanto in Missouri in 2019. A jury ultimately sided with him on a failure-to-warn claim, awarding $1.25 million in damages. Missouri courts upheld that verdict, rejecting Monsanto’s argument that federal law preempts state-based claims about labeling.
Monsanto has now taken that argument to the Supreme Court, contending that FIFRA explicitly bars states from imposing labeling requirements that differ from or add to federal standards. The company also argues that allowing juries to impose liability based on labeling decisions already approved by the EPA would undermine a uniform national regulatory system.
Supporting Monsanto, the federal government has warned that permitting state-level variations could create inconsistent rules across the country. Such a system, it argues, would conflict with Congress’s intent to centralize pesticide regulation and scientific assessment at the federal level.
Durnell, however, argues that his lawsuit does not conflict with federal law. He maintains that FIFRA does not give the EPA absolute authority over labeling disputes in court and that state laws requiring adequate warnings are consistent with federal standards prohibiting misleading labels. In his view, juries can evaluate whether a warning is sufficient without contradicting federal law.
The stakes extend far beyond a single lawsuit. More than 100,000 similar claims have been filed against Monsanto, now owned by Bayer. The company has already faced billions of dollars in liability and recently proposed a multibillion-dollar settlement to resolve current and future cases tied to Roundup.
The dispute also intersects with broader policy debates. In February, President Donald Trump issued an executive order insisting on the importance of glyphosate to American agriculture and national security.
When the Supreme Court hears arguments, the justices will be weighing not only legal doctrine but also competing views of science, federalism, and risk regulation. A ruling in Monsanto’s favor could significantly limit the ability of individuals to bring state-law claims over pesticide labeling. A decision for Durnell could preserve those claims and potentially expose manufacturers to continued litigation across multiple jurisdictions.
The court is expected to issue its decision by early summer, with consequences likely to ripple across the agricultural industry, regulatory policy, and the legal landscape surrounding product liability.
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