SAN FRANCISCO (CN) - Defending a decision by American regulators to deviate from cancer-risk assessment guidelines in evaluating the controversial active ingredient in Monsanto's Roundup weed killer, a Canadian toxicologist testified Thursday that the guidelines aren't the "Ten Commandments."
The statement by McMaster University professor Warren Foster came in response to a line of questioning in the first-ever jury trial over Roundup's alleged carcinogenicity, aimed at showing that Monsanto and the U.S. Environmental Protection Agency colluded to declare the ingredient safe after the World Health Organization's International Agency for Research on Cancer (IARC) classified it as a probable human carcinogen.
IARC's 2015 finding triggered hundreds of lawsuits against Monsanto in the United States, including plaintiff Dewayne Johnson's.
Johnson, 46, sued the agrichemical company in 2016 after being diagnosed with a cutaneous form of non-Hodgkin lymphoma that caused cancerous lesions to form over most of his body. He says he developed symptoms after he was twice drenched in Roundup and regularly had it drift into his face while spraying schoolyards for his job with the school district in Benicia, a suburb of San Francisco.
He also claims Monsanto has known for decades that Roundup is carcinogenic but didn’t disclose it for fear of disrupting its multi-billion dollar global business.
On cross-examination Thursday, Johnson's attorney Brent Wisner read from a report written by an independent Scientific Advisory Panel convened by the EPA to review its 2016 assessment that glyphosate is safe. "Many members" of the panel, the report read, concluded that the EPA "did not provide convincing evidence of a lack of carcinogenic effects" of glyphosate, said Wisner, who is with Baum Hedlund Aristei Goldman.
The dissenting members stated the research instead showed that glyphosate is a potential carcinogen, he said.
The panel flagged the EPA's failure to explain why it used historical control data in some analyses and not in others, he said, potentially introducing bias into its evaluation and deviating from its own guidelines requiring employees to document their processes when they do so.
"These are guidelines; they're not tablets from the Mount," Foster replied. "It's not unreasonable to deviate from the guidelines on occasion as long as you justify why you've done it."
"Do you know why the EPA was willing to deviate from the guidelines for Monsanto?" Wisner asked.
Foster said the EPA has deviated from its guidelines "on other occasions."
Earlier in the day, Foster testified that some of the 12 rodent studies researchers generally use to evaluate glyphosate's carcinogenicity are limited and that the totality of the evidence shows no link between the chemical and cancer.
Foster's conclusions contrasted with those of Christopher Portier, a biostatistician who testified at the beginning of trial that glyphosate can cause non-Hodgkin lymphoma.
Portier said one study in which glyphosate was applied to the skin of mice suggested that the chemical is a tumor promoter. Two other studies in which rodents dosed with large amounts of glyphosate developed cancer supported his conclusion that glyphosate is carcinogenic, he said.
But Foster testified Thursday that the latter two studies used "exceedingly high" doses - about four to five times higher than recommended - that don't exist in the real world.
More importantly, he said, doses above the recommended dose levels always induce cancer, rendering the results meaningless.
"I can introduce malignant tumors, and I can give you teratogenic events. I can give you whatever you want," he told Hollingsworth LLP attorney Kirby Griffis, who represents Monsanto.
On cross-examination, Wisner noted that the Scientific Advisory Panel criticized the EPA's practice of assigning low weights to studies using high doses of glyphosate, something Foster also did in his evaluation.
"You weighted them after Monsanto hired you," Wisner said, referring to the approximately $65,000 Monsanto paid Foster to testify on its behalf. "You weighted that they all go in the trash can."
Displeased with Wisner's comment, Foster pushed back.
"I take exception with that, because as a scientist, the only thing I've got is objectivity," he said. "The only thing I can hang on my wall when I go home is I looked at it in an objective way."
Glyphosate is the most widely used agrichemical in history. Monsanto introduced it in 1974, and its use exploded in 1996 after the company began selling “Roundup-ready” seeds engineered to resist the herbicide. 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.
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.
In June, German pharmaceutical giant Bayer completed its $63 billion acquisition of Monsanto after approval by U.S. and European regulators. Bayer told Reuters that same month it plans to retire the Monsanto name.
Monsanto expects to rest its case Friday, Aug. 3 or Monday, Aug. 6.
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