In a statement, Monsanto said, “Glyphosate is not a carcinogen.”

It added: “The allegation that glyphosate can cause cancer in humans is inconsistent with decades of comprehensive safety reviews by the leading regulatory authorities around the world. The plaintiffs have submitted isolated documents that are taken out of context.”

The E.P.A. had no immediate comment, and Mr. Rowland could not be reached immediately.

Monsanto also rebutted suggestions that the disclosures highlighted concerns that the academic research it underwrites is compromised. Monsanto frequently cites such research to back up its safety claims on Roundup and pesticides.

In one email unsealed Tuesday, William F. Heydens, a Monsanto executive, told other company officials that they could ghostwrite research on glyphosate by hiring academics to put their names on papers that were actually written by Monsanto. “We would be keeping the cost down by us doing the writing and they would just edit & sign their names so to speak,” Mr. Heydens wrote, citing a previous instance in which he said the company had done this.

Asked about the exchange, Monsanto said in a second statement that its “scientists did not ghostwrite the paper” that was referred to or previous work, adding that a paper that eventually appeared “underwent the journal’s rigorous peer review process before it was published.”

David Kirkland, one of the scientists mentioned in the email, said in an interview, “I would not publish a document that had been written by someone else.” He added, “We had no interaction with Monsanto at all during the process of reviewing the data and writing the papers.”

The disclosures are the latest to raise concerns about the integrity of academic research financed by agrochemical companies. Last year, a review by The New York Times showed how the industry can manipulate academic research or misstate findings. Declarations of interest included in a Monsanto-financed paper on glyphosate that appeared in the journal Critical Reviews in Toxicology said panel members were recruited by a consulting firm. Email traffic made public shows that Monsanto officials discussed and debated scientists who should be considered, and shaped the project.

“I think it’s important that people hold Monsanto accountable when they say one thing and it’s completely contradicted by very frank internal documents,” said Timothy Litzenburg of the Miller Firm, one of the law firms handling the litigation.