The U.S. Environmental Protection Agency is backing the Monsanto Co.’s claim that federal law should have pre-empted a lawsuit alleging its Roundup herbicide causes cancer.

Last year, a jury decided that plaintiff Edwin Hardeman developed non-Hodgkin’s lymphoma due to exposure to the chemical, resulting in a $25 million judgment against Monsanto that the company is now challenging.

However, the EPA has determined that glyphosate — the active ingredient in Roundup — shouldn’t be labeled as a cancer risk, which precludes the lawsuit’s allegation that such warnings are necessary, the agency said.

“It actually does violate the EPA regulation as well as the registration determination on the label,” said Jonathan Brightbill, an attorney for the agency, during recent oral arguments before the 9th U.S. Circuit Court of Appeals.

The pesticide industry, represented by the Croplife America organization, has argued the “issues in the case reach well beyond Roundup and glyphosate” and urged the 9th Circuit to overturn the judgment against Monsanto.

The lawsuit raises the “fundamental question” of whether EPA labeling requirements that are based on “expert scientific judgments” under federal pesticide law can be “overridden by the verdicts of lay juries under state law across a wide array of regulated pesticides.”

Monsanto claims that a federal judge should have thrown out the complaint before a jury could even hear the plaintiff’s allegations, which were supported by flawed and unreliable testimony that should have been excluded.

“The trial in this case never should have been held because the claims are pre-empted and because the causation opinions that plaintiff’s experts offered did not pass a proper gate-keeping analysis,” said Seth Waxman, Monsanto’s attorney.

Monsanto and other pesticide manufacturers are actually disallowed from labeling glyphosate as a cancer risk due to a 2019 EPA letter that’s “binding and has the force of law,” Waxman said.

A company cannot be held liable for failing to do something that’s prohibited by the EPA, which authorizes pesticide labels, he said. “That’s the textbook case of impossibility pre-emption.”

David Wool, the plaintiff’s attorney, countered that the damages were caused by the entire formulation of Roundup, including surfactant chemicals, rather than just the active ingredient glyphosate.

The EPA’s letter to pesticide manufacturers does not amount to a regulatory decision under the agency’s jurisdiction, which would require notice-and-comment procedures and other steps, Wool said.

“This letter doesn’t purport to exercise any of that authority,” he said. “It’s merely an agency musing.”

If the EPA had gone through the process of rejecting a pesticide label that warned of cancer risk, that could have had a pre-emptive effect, but that’s not what happened in this case, he said.

“There is no such regulation here and neither Monsanto or the government points to one,” Wool said. “No adequate label change has been formally rejected.”

The plaintiff’s arguments were buttressed by the State of California, which considers glyphosate a cancer-causing agent.

While it’s true that manufacturers can’t sell pesticides without EPA registration under the Federal Insecticide, Fungicide and Rodenticide Act, that does not bar the plaintiff from suing Monsanto in this case, said Andrew Jay Wiener, California’s deputy attorney general.

“FIFRA expressly says that registration can’t immunize a manufacturer from liability,” Wiener said.