Lawyers are gearing up to flood the courts with thousands more lawsuits after a jury last week awarded more than $289 million to a former groundskeeper who said he got cancer from Monsanto's weed killer.

So far, more than 4,000 people have sued over Roundup, most in Missouri and California state courts. About 470 cases have been coordinated in California federal court as multidistrict litigation. Friday's verdict came in a case that was a bit of an outlier: The plaintiff, Dewayne “Lee” Johnson, went to trial first in San Francisco Superior Court because of his poor health prognosis.

Monsanto Hit With $289M Verdict Over Roundup Weed Killer

But the jury's verdict, which included $250 million in punitive damages, was heard loud and clear by plaintiffs lawyers who had cases waiting in the wings.

“This couldn't send a clear enough signal to Monsanto that they are in trouble in these cases, and we have evidence to prove that case wherever it's tried,” said R. Brent Wisner of Los Angeles-based Baum Hedlund Aristei Goldman, who represented Johnson.

He estimated that about 10,000 people had retained attorneys — and more are expected.

“I had 200 calls this morning from people wanting to sign up,” he said.

Micah Dortch of the Potts Law Firm in Dallas said he has more than 120 clients who planned to file their Roundup cases within the next 30 days.

He said he had been waiting on the Johnson verdict “to find out if juries like the science.”

Brian Kabateck, of Kabateck Brown Keller in Los Angeles, hasn't filed any Roundup cases because he initially wasn't convinced there was enough scientific evidence about the product's link to cancer. But the jury's “breathtakingly large amount of punitive damages” on Friday could change his mind.

“I found this very intriguing. When these cases were initially filed, I did not necessarily believe that this was a potentially viable case, and stayed on the sidelines,” he said. “We, like many people, are re-evaluating our decision on this today.”

Plaintiff's Lawyer Asks Jurors for $412M Verdict Against Monsanto

Monsanto has vowed to appeal the verdict. It also has filed a motion for mistrial, citing a “series of calculated, intentional and improper statements during closing argument, several over the court's sustained objections, designed solely to inflame the prejudice and passion of the jury against Monsanto.”

In an interview, Monsanto Vice President Scott Partridge said: “Plaintiffs lawyers conducted themselves in a fashion where they were repeatedly admonished by the judge for their conduct. The judge was so disturbed at one of the motions, she took it under advisement and, the following morning, admonished counsel and instructed the jury to disregard the conduct.”

In particular, they compared Monsanto to Big Tobacco, invited jurors to “change the world” with their verdict and, in closing argument, told the jury there was champagne waiting on ice at a Monsanto boardroom.

“There is no evidence that there were champagne bottles on ice in a Monsanto boardroom,” Partridge said. “That is the type of conduct that is improper and designed solely to inflame the jury.”

The company also plans to argue that the plaintiff didn't make his case, given that more than 800 studies and reviews, and the U.S. Environmental Protection Agency and regulatory agencies around the world, have found Roundup's key ingredient, glyphosate, does not cause cancer.

Johnson's lawyers didn't get everything they wanted: Wisner had asked jurors for $100 million more in punitive damages. It's unclear how the jury calculated its punitive damages.

“At the end of the day, though, it's still a pretty considerable verdict,” Wisner said. “I chalk that up to a jury that was very deliberate in what they were doing. The jury, unlike pretty much any other jury I've seen in my life, was super engaged.”

The next Roundup trial is on Oct. 22 in St. Louis. Plaintiffs lawyers Rudie Soileau of Lundy, Lundy, Soileau & South, and Robin Greenwald of New York's Weitz & Luxenberg will be handling that trial. Soileau said the case involves an Arkansas resident in his 40s, diagnosed with non-Hodgkin's lymphoma after using Roundup at his own home and other neighbors' yards.

At a press conference following the verdict, Wisner told the media that the trial in St. Louis, where Monsanto has its headquarters, could feature corporate executives in person and a “lot more evidence.”

More important, he said, is “we now have a way forward.”

Wisner said, “Monsanto now has an option to do right by all the people that have been hurt, and do right by Mr. Johnson, and do right by everybody else who could be affected by this product.”

Xiumei Dong contributed to this report.