Sprinklers run as a farmworker walks through a broccoli field in Salinas, Calif. on Sept. 4, 2018. (AP Photo/Jae C. Hong, File)

OAKLAND, Calif. (CN) – The maker of the world’s most popular herbicide could have warned the public about possible cancer risks, but chose not to, a controversial expert witness in a trial over a couple’s claims that Roundup caused their cancers testified Wednesday.

Back in 1985, the Environmental Protection Agency classified glyphosate, the main chemical compound in Roundup, as a “Class C” possible human carcinogen. This came after an EPA oncogenicity study that found kidney tumors in male mice exposed to glyphosate.



“This had significant regulatory implications,” Charles Benbrook told the jury Wednesday. Benbrook, an agricultural economist, was brought in to testify about the EPA’s regulatory framework for herbicides. He said a classification as a possible human carcinogen would essentially block the EPA from expanding glyphosate tolerances and “had a direct effect on market potential for future Roundup sales.”



Brent Wisner, representing plaintiffs Alva and Alberta Pilliod, showed the jury a memo sent by Monsanto employee Lyle Gingrich on February 22, 1985, shortly after the EPA released its statement. The memo said colleague Fred Johansen had asked “short of a new study finding tumors in the control groups, what can we do to get this thing off of Group C?”



“Responding to question from FJ, Dr. Farber said it was an extremely close call and that the EPA remains open to any new information that would make their decision easier,” the memo continued, referring to Dr. Theodore Farber, at the time head chief Monsanto toxicologist.



In April, Monsanto hired pathologist Dr. Marvin Kuschner to look at the kidney slides, and lo and behold, he did find a kidney tumor in one of the mice not dosed with glyphosate.



This was strange, Benbrook said, since EPA statistician Dr. Herbert Lacayo had calculated the odds of tumors being found in the control group back in February and found it considerably small. Monsanto had argued that the four tumors had been false positives, and Lacayo disagreed, saying that false positives are “less likely to occur with rare tumors. And the tumors in question are rare,” and that Monsanto “will have to demonstrate that this positive result is false.”



“Our viewpoint is one of protecting the public health when we see suspicious data,” Lacayo wrote. “It is not our job to protect registrants from false positives.”



The EPA’s scientific advisory panel was concerned by the sudden appearance of a tumor in the control group after Kuschner’s study, but nonetheless classified glyphosate as a Group D chemical, “not classifiable as to human carcinogenicity.”



The EPA asked for more studies, but, as Benbrook testified, “No other study was done.”



Benbrook’s testimony has been highly contested by the defense, both before and during trial. Monsanto’s attorneys moved to exclude his testimony altogether, and in mid-March, Judge Winifred Smith issued an order limiting Benbrook to explaining regulations and herbicide registration requirements.



She ordered that Benbrook could not testify on whether Monsanto misled the EPA, or about whether the EPA would have approved an amendment to the Roundup label.



She also ordered that Benbrook could not testify as to Monsanto’s motive or intent, or on standard of care warnings in the industry.



Outside the presence of the jury on Wednesday morning, Monsanto attorney Eugene Brown objected to the scope of Benbrook’s planned testimony, particularly an article Benbrook wrote entitled, “How did the US EPA and IARC Reach Diametrically Opposed Conclusions on the Genotoxicity of Glyphosate-based Herbicides?”



In 2015, the World Health Organization’s International Agency for Research on Cancer deemed glyphosate a probable carcinogen, while regulators in Europe, Canada and the United States, including the EPA, have concluded glyphosate is safe.



Benbrook said the difference lay in IARC’s reliance on mostly peer-reviewed studies, while the EPA based its findings on studies either performed or commissioned by pesticide registrants like Monsanto.



Wisner protested that the jury had already seen the article when toxicologist Dr. William Sawyer testified about it last week, and that the defense had already been supplied with Benbrook’s expert report.



He accused Monsanto attorneys of “Sandbagging us on the morning [Benbrook] is on the stand.”



Brown stood firm on the issue. “He is an agricultural economist. That does not qualify him to read articles and form opinions and then come in and proselytize to the jury.”

“There’s so much factual inaccuracy here,” Wisner said.



“By virtue of publishing an article does not make someone an expert on any point,” Brown told Judge Smith.

“We specifically gave them the report,” Wisner said. “Mr. Brown is not familiar with this litigation. I’ve been doing this for the last three years.”

“You’ve been doing something,” Brown sniped.



Smith, who said she had been blindsided by the objection to Benbrook after she’s already issued her order limiting his testimony, said she would not make any rulings but that the parties would have to “wing it.”



“I’ll entertain objections as we go along,” she said. Brown fully availed himself of this, and objected no less than 50 times throughout Wisner’s direct examination.



Glyphosate use has quadrupled in the United States since 1997, Benbrook said. More than 2.6 billion pounds of the chemical were spread on U.S. farmlands and yards between 1992 and 2012, according to the U.S. Geological Survey.



Benbrook also noted during testimony that while Monsanto’s safety sheet for its own employees recommends that the product be used with skin protection, chemical resistant clothing, face shields and shoe coverings, it puts none of these warnings on labels on Roundup product labels and has never proposed amending it.



The Pilliods both developed non-Hodgkin lymphoma after decades of consistent, unprotected Roundup use, and a large part of their case rests on the claim that Monsanto knew its product was toxic but deliberately did not warn consumers to use protective clothing.