The Environmental Protection Agency has consistently found no causal link between glyphosate-based pesticides and a heightened risk of cancer. As a result, EPA never required pesticide manufacturers to include cancer risk on glyphosate labels. But in 2019, John Durnell sued Monsanto Company anyway, alleging that Monsanto's glyphosate-based Roundup products caused him to develop non-Hodgkin's lymphoma and that the product's label failed to warn him of the risk. Durnell's claim raised serious questions about whether states may hold pesticide manufacturers liable for risks associated with their products even when they comply with all federal labeling requirements.
In Monsanto v. Durnell, the Supreme Court held that federal law preempts such claims. The Supremacy Clause of the U.S. Constitution permits federal law to displace state laws that regulate the same subject. And the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) preempts all state laws that impose "additional" or "different" labeling requirements on pesticide manufacturers. That statute, the Court held, displaces state tort claims that would require pesticide manufacturers to warn consumers that glyphosate causes cancer. The Court's decision will ensure that pesticide manufacturers and farmers face a consistent and predictable set of labeling requirements across all 50 states.
FIFRA Authorizes EPA to Regulate Pesticides
FIFRA authorizes EPA to regulate pesticides and pesticide labels. Before registering a new pesticide, EPA must determine that the pesticide "will not generally cause unreasonable adverse effects" on human health and the environment. The label must include all warnings necessary and adequate to protect human health and the environment, while not containing false or misleading statements. After EPA approves a pesticide's label at registration, manufacturers are legally required to use that label. Subject to minor exceptions, manufacturers may change an approved label only with EPA's approval or instruction.
Durnell Sues Monsanto for Failure-to-Warn Claim
Monsanto manufactures and distributes the Roundup brand of glyphosate-based pesticides. EPA has repeatedly evaluated glyphosate and found no causal association with higher cancer risks. Regulators in Canada, Australia, Japan, and the European Union agree with EPA's findings.
In 2019, a farmer, John Durnell, sued Monsanto Company in Missouri state court. Durnell used Roundup products for about 20 years and alleged that using the pesticide had caused his cancer, non-Hodgkin's lymphoma. Durnell brought a failure-to-warn common law tort claim, because he claimed that Monsanto failed to include a cancer warning on Roundup's label. A jury awarded Durnell more than $1 million, and the Missouri Court of Appeals affirmed, prompting Monsanto to seek review before the Supreme Court.
The Supreme Court Corrects the Missouri Court of Appeals
The Supreme Court focused on the scope of FIFRA's express preemption provision, which displaces state laws imposing directives for "labeling or packaging in addition to or different from" FIFRA's "requirements." The parties accepted the validity of this provision but disagreed as to whether FIFRA's "requirements" include EPA's regulations governing the registration and labeling of pesticides. Durnell argued that FIFRA's requirements consist only of the statute's prohibition on mislabeling and its directive that labels include adequate and necessary warnings. But Monsanto countered that EPA's regulations are also FIFRA requirements because they are promulgated pursuant to EPA's authority under the same subchapter.
In a 7-2 opinion by Justice Kavanaugh, the Supreme Court sided with Monsanto, holding that FIFRA expressly preempts state-law failure-to-warn claims. The court explained that FIFRA empowers EPA to promulgate regulations that implement FIFRA's requirements, so EPA's regulations constitute FIFRA "requirements" and can preempt state law. Because those regulations require manufacturers to use labels approved by EPA, Monsanto must use a Roundup label that does not include cancer warnings unless EPA approves or requires a change. Durnell's failure-to-warn claim would therefore impose additional requirements by requiring Monsanto to add cancer warnings to its label.
Justice Jackson dissented, joined by Justice Gorsuch. She argued that EPA's approval of a pesticide label does not create any new FIFRA requirements entitled to preemptive effect. Instead, in the dissent's view, state-law failure-to-warn claims merely mirror FIFRA's generalized requirement that pesticide labels contain no "false or misleading" language. She further argued that EPA's approval of a pesticide's label is not conclusive of the pesticide not being misbranded.
The Decision Benefits Farmers, Manufacturers, and the Courts
This holding extends beyond Roundup and Monsanto. Glyphosate-based pesticides are effective, inexpensive, and lower in acute and chronic toxicity than other similar products on the market. Thus, clarifying the labeling of these products will benefit farmers who use this pesticide, as well as consumers who benefit from the crops. This holding will also allow for the continued use of products like Roundup, which will reduce the cost of developing new products that do not use glyphosate.
The Court's decision also creates greater certainty for manufacturers and stability for courts. By defining the extent of FIFRA, the decision affords uniformity and consistency to manufacturers who meet the labeling requirements for glyphosate-based pesticides, ensuring that products sold across state lines will not require the use of different labels. And by resolving the circuit split on FIFRA preemption, the Supreme Court has reduced litigation costs and removed a significant burden from the courts. Durnell is one of more than 100,000 plaintiffs suing Monsanto for not including a cancer label on Roundup. To the extent those cases involve failure-to-warn claims, such claims will likely encounter the same preemption problem.
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The authors thank Alissa N. Dobrinsky, a summer associate in our Los Angeles office, for her assistance in writing this article.