RoundUp weed killer.

In a big win for Monsanto Co., a federal judge in San Francisco has bifurcated the first bellwether trials in the multidistrict litigation over the herbicide Roundup, the first of which starts next month.

U.S. District Judge Vince Chhabria of the Northern District of California ruled Thursday that three upcoming trials would each have two phases. The first would focus on whether Roundup’s key ingredient, glyphosate, caused a plaintiff’s diagnosis of non-Hodgkin’s lymphoma and, if so, how much the jury should award in compensatory damages. The second, if needed, would address Monsanto’s liability and punitive damages.

Monsanto, which sought so-called “reverse bifurcation” of the trials, argued that juror confusion over conflicting regulatory findings led to last year’s $289 million verdict in San Francisco Superior Court. Bifurcating the trial could potentially stymie a key trial theme from the plaintiffs’ legal team: That Monsanto influenced the scientific studies backing the safety of glyphosate.

“Although this type of bifurcation is unusual and should be done with caution—both generally and in the context of MDL bellwether trials—it is warranted here,” Chhabria wrote in his decision. “A significant portion of the plaintiffs’ case involves attacks on Monsanto for attempting to influence regulatory agencies and manipulate public opinion regarding glyphosate. These issues are relevant to punitive damages and some liability questions. But when it comes to whether glyphosate caused a plaintiff’s NHL, these issues are mostly a distraction, and a significant one at that.”

Chhabria heard arguments on his order at a hearing Friday.

The move is the latest by Monsanto to prevent a repeat of last year’s verdict, later lowered to $78.5 million, as it gears up for the first trials in federal court. Last month, Monsanto raised concerns about juror bias, given that next month’s trial is in San Francisco. On Thursday, Monsanto filed a flurry of court documents to toss all three cases, either based on federal pre-emption grounds or by striking the plaintiffs’ experts, including those testifying on causation.

Monsanto’s parent company, Bayer AG, praised the bifurcation order.

“The Court’s decision to keep the focus of the trial on the extensive science relevant to human health is encouraging,” the company said in an emailed statement. “Bayer is confident that this science demonstrates our glyphosate-based herbicides are safe for use and believes it will ultimately be determinative in this litigation.”

One of the lead plaintiffs’ attorneys, R. Brent Wisner of Baum, Hedlund, Aristei & Goldman in Los Angeles, said in an email: “The Court wants to focus on the science. And, Monsanto believes that focusing on science will help them avoid another big verdict. Monsanto is mistaken. The science is and has always been the strongest part of our case. And we are confident that no matter how many obstacles the court or Monsanto attempt to put in our way, we will win.”

Chhabria, who bifurcated the entire multidistrict litigation to deal with causation issues last year, has been skeptical about the plaintiffs’ scientific evidence. In a July 10 ruling, he allowed plaintiffs’ attorneys to put on what he called “shaky” but “admissible” evidence that glyphosate caused non-Hodgkin’s lymphoma. But he called it a “very close question” and a “daunting challenge.”

Monsanto’s chief concern is plaintiffs’ reliance on a 2015 decision by the International Agency for Research on Cancer, or IARC, classifying glyphosate as a possible carcinogen. Other regulatory groups, such as the U.S. Environmental Protection Agency, have found no such link.

“What the actual regulatory bodies and IARC have said about the science is not a substitute for the jury’s own evaluation of the science,” wrote Monsanto attorney Brian Stekloff, of Wilkinson Walsh + Eskovitz in Washington, D.C., in a brief last month. “But the temptation would be great for lay jurors to simply assume that either the expert regulators or IARC are correct and end their analysis there, particularly given that the regulators and IARC have reached such disparate conclusions.”

Stekloff noted that both phases could take about three weeks and that experts for each would not overlap. But plaintiffs’ attorneys, in their own brief, disagreed.

Wisner wrote that the bifurcation action was “unheard of in the modern MDL bellwether process” and would “create structural and substantive prejudice against plaintiffs.”

“Substantively, if plaintiffs are prevented from presenting evidence about how Monsanto influenced and corrupted science and regulators, then the jury will be left with a nagging question—if this product can cause cancer, why has it been on the market for over forty years with no warning?” he wrote.

Chhabria’s order acknowledged some of the plaintiffs’ concerns. He wrote that he could instruct jurors not defer to regulatory agencies in deciding whether glyphosate caused cancer but to decide based on the evidence at trial—an idea put forth by plaintiffs’ lawyers in their brief. He also wrote that jurors would likely hear about IARC’s decision and allegations that Monsanto manipulated scientific studies during the first phase. In a footnote, he wrote that he might reconsider bifurcation after the first trial, if necessary.

But he disagreed with plaintiffs’ lawyers that bifurcation would diminish the value of the bellwether trials in guiding both sides to a settlement of more than 10,000 cases brought over Roundup nationwide.

“Monsanto has already lost a $78.5 million judgment in state court, in a trial that was not bifurcated,” he wrote. “If Monsanto were also to lose on the causation question in a bifurcated trial in federal court, the parties would learn a great deal about Monsanto’s chances of success (or lack thereof) in all future cases, however structured.”