SAN FRANCISCO (CN) – A federal judge on Tuesday refused to exclude "shaky" expert opinions that the world's most popular weed killer causes cancer in humans, advancing more than 400 lawsuits against agrichemical giant Monsanto.
"The court cannot go so far as to say these experts have served up the kind of junk science that requires exclusion from trial," U.S. District Judge Vince Chhabria wrote in a 68-page ruling denying Monsanto's motions to terminate the lawsuits for lack of credible evidence.
The decision comes one day after the first trial over an alleged link between glyphosate in Monsanto's Roundup weed killer and the development of non-Hodgkins lymphoma in humans kicked off in a separate case in state court.
Despite finding problems with some methods used by six experts who concluded glyphosate causes cancer in humans, Chhabria deemed three plaintiffs' expert opinions and one partial opinion credible enough to go to a jury.
"The question at this phase is not whether the plaintiffs' experts are right," Chhabria wrote. "The question is whether they have offered opinions that would be admissible at a jury trial."
In a statement, Monsanto focused on the court's decision to exclude two plaintiffs' expert opinions and to "severely limit" one scientist's opinion.
"The court refers to the remaining experts as 'shaky' and acknowledged that the plaintiffs face a 'daunting challenge' in the next phase of the litigation because 'the evidence between glyphosate exposure and NHL in the human population seems rather weak,'" Monsato said in a statement, quoting Chhabira's ruling and using the acronym “NHL” for non-Hodgkins lymphoma.
But plaintiffs' attorney Kathryn Forgie, of Andrus Wagstaff in Oakland, California, said she believes the expert opinions will withstand scrutiny on the witness stand because the scientists – Dr. Christopher Portier, Dr. Beate Ritz, and Dr. Dennis Weisenburger – come from prestigious institutions and used sound, scientific methods in their research.
"It's pretty clear that the quality of our experts is impressive," Forgie said. "I think we have some of the strongest evidence I've seen in this kind of case."
Chhabria called his decision to admit the three expert opinions and deny Monsanto's motion for summary judgment a "close question."
"The evidence, viewed in its totality, seems too equivocal to support any firm conclusion that glyphosate causes NHL," the judge wrote. "This calls into question the credibility of some of the plaintiffs' experts, who have confidently identified a causal link."
The judge emphasized that a 2015 conclusion by the World Health Organization’s International Agency for Research on Cancer that glyphosate is "probably carcinogenic to humans" was merely a hazard assessment, not a scientific conclusion that can be relied upon at trial.
According to Monsanto, more than 800 scientific studies and reviews, including those conducted by the U.S. Environmental Protection Agency and National Institutes of Health, found no link between glyphosate and cancer.
Finding that multiple studies have resulted in contradictory findings on whether glyphosate causes cancer, Chhabria ruled only a jury can assess the adequacy of such evidence.
"All the studies leave certain questions unanswered, and every study has its flaws," Chhabria wrote in his ruling.
The next step will be discovery. Forgie said the plaintiffs will soon start deposing Monsanto employees and any new defense experts as both sides prepare for trial.
Monsanto said it will continue to fight the lawsuits with "robust evidence that proves there is absolutely no connection between glyphosate and cancer."
"We have sympathy for anyone suffering from cancer, but the science clearly shows that glyphosate was not the cause," the company said in a statement Tuesday.
Glyphosate, the active ingredient in Roundup, is the most widely used agrichemical in history. Monsanto introduced it in 1974, and its use exploded after Monsanto began selling “Roundup-ready” seeds – engineered to resist glyphosate – in 1996. More than 2.6 billion pounds of glyphosate was spread on U.S. farmlands and yards between 1992 and 2012, according to the U.S. Geological Survey.
Monsanto earns $1.9 billion a year from Roundup and $10.2 billion from “seeds and genomics,” most of that category being Roundup-ready seeds.
Last month, German pharmaceutical giant Bayer completed its $63 billion purchase of Monsanto after approval from U.S. and European regulators. Bayer told Reuters in June that it plans to retire the Monsanto name.
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