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In the late 1990s, John Durnell began using the weedkiller Roundup to help tend to the community spaces in his neighborhood in St. Louis. Since then, he and roughly 170,000 other users have been diagnosed with non-Hodgkin’s lymphoma and related cancers associated with extended exposure to glyphosate, Roundup’s key ingredient and a probable carcinogen. Many of them have filed suit against Monsanto, now owned by Bayer. But out of those 60,000 still-active lawsuits, only Durnell’s case reached the Supreme Court. Now, it has become something much larger than one man’s lawsuit: a decision that federal regulatory approval can permanently shield corporations against accountability for harm, regardless of what their own internal documents and science later reveal.

In Monsanto v. Durnell, the question before the court was whether the Federal Insecticide, Fungicide, and Rodenticide Act preempts state failure-to-warn lawsuits when the Environmental Protection Agency has not required the warning. Monsanto argued preemption on two grounds. First, as the EPA did not require a cancer warning at the time of product registration, a state tort claim seeking damages for a lack of such warning should be considered as an additional burden beyond FIFRA’s labeling standard, necessitating express preemption. Second, as a manufacturer cannot change EPA-approved labeling unilaterally, complying with both state and federal law would be impossible, preempting state suits. Durnell argued that FIFRA explicitly allows state authority over pesticide use, and given current scientific knowledge, this state tort claim is consistent with FIFRA’s labeling standard. On Thursday, the Supreme Court handed down a 7–2 decision broadly in favor of Monsanto, ruling that FIFRA expressly preempts Durnell’s state........

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