Although Monsanto has long claimed that glyphosate, the active ingredient in the weed killer Roundup, is safe and does not cause cancer, unsealed court documents tell a potentially different story. Emails and memos from Monsanto reveal a coordinated strategy to manipulate the debate about the safety of glyphosate—to the company’s advantage.
Monsanto strategy #1: Start with a conclusion and then twist the science to defend it
Monsanto’s approach has never been to objectively assess the cancer-causing potential of glyphosate. Rather, the company relentlessly defends its conclusion that glyphosate is safe by funding studies and assessments to support this claim.
Internal Monsanto emails from 2012 discuss the difficulty of synthesizing the data on genotoxicity—the ability to damage cell DNA and lead to mutations, including cancer. One employee wrote:
After they got all the studies amassed into a draft manuscript, it unfortunately turned into such a large mess of studies reporting genotoxic effects, that the story as written stretched the limits of credibility among less sophisticated audiences….But even though we feel confident that glyphosate is not genotoxic, this becomes a very difficult story to tell given all the complicated ‘noise’ out there.
In other words, the available data showed some evidence of glyphosate’s genotoxicity. The company responded by hiring scientist David Kirkland and former Monsanto employee Larry Kier to author a paper debunking these findings. The paper concluded that glyphosate is not genotoxic to human cells, and the Environmental Protection Agency (EPA) even used it its 2016 assessment that glyphosate was not linked to cancer.
Monsanto used this approach again in 2015, after the World Health Organization’s (WHO) International Agency for Research on Cancer concluded that glyphosate is “probably carcinogenic to humans.” An internal PowerPoint outlines Monsanto’s strategy for countering this damning classification. One suggestion was to publish a paper analyzing the animal data that the WHO used in its cancer assessment, noting that the “majority of writing can be done by Monsanto, keeping OS$ [costs] down.” It suggested recruiting external scientists like Helmut Greim, who coauthored a Monsanto-funded analysis the following year that (unsurprisingly) concluded that glyphosate is not carcinogenic to laboratory animals.
This is not how science is supposed to work; you don’t begin with a conclusion and twist the science to defend it. But the EPA’s system for assessing the public health risk posed by pesticides like Roundup relies heavily on industry-funded science, which makes the process vulnerable to this kind of predetermined conclusion driven approach.
Monsanto strategy #2: Ghostwrite papers and pay “independent” scientists to sign them
Kirkland received about $2,200 a day to work on the paper and Monsanto cultivated him as one of its go-to scientists for defending the safety of its products. Kier is also mentioned in several emails, including a 1999 email where a colleague writes, “The only person I think that can dig us out of this ‘genotox hole’ is the Good Dr. Kier.” Monsanto knows which scientists to pay to come up with the results it’s looking for—and sometimes Monsanto staff ghostwrite these papers themselves.
In a 2015 email, Monsanto staff suggested publishing additional papers on genotoxicity: “An option would be to add Greim and Kier or Kirkland to have their names on the publication, but we would be keeping the costs down by us doing the writing and they would just edit and sign their names so to speak.” The employee mentions that the same approach was taken in a 2000 study. Greim, Kier and Kirkland—along with a handful of other scientists named in internal emails and memos—all served on the 2016 “expert” panel that Monsanto commissioned to counter the WHO’s classification of glyphosate as probably carcinogenic. Monsanto claims that a consulting group assembled the “independent” panel, but these emails show that Monsanto handpicked the scientists.
Monsanto strategy #3: Avoid scientists who don’t tow the line
Not all scientists who consult for Monsanto produce favorable results. As one Monsanto employee bemoaned: “Data generated by academics has always been a major concern for us in the defense of our products.” Monsanto faced this challenge in 1999 after enlisting James Parry, an expert in genotoxicity, to conduct an assessment on the available literature.
Parry found some evidence of glyphosate’s genotoxicity and gave suggestions for additional tests that could cover gaps in knowledge. This is not the answer that Monsanto was looking for. One Monsanto employee vented in an email, “Has he ever worked with industry before?”
Monsanto employees discussed whether or not to continue the relationship with Parry. One wrote:
Let’s step back and look at what we are really trying to achieve here. We want to find/develop someone who is comfortable with the genetox profile of glyphosate/Roundup and who can be influential with regulators and Scientific Outreach operations when genotox. issues arise. My read is that Parry is not currently such a person, and it would take quite some time and $$$/studies to get him there. We simply aren’t going to do the studies Parry suggests. Mark, do you think Parry can become a strong advocate without doing this work Parry [sic]? If not, we should seriously [emphasis in the original] start looking for one or more other individuals to work with….[We] are currently very vulnerable in this area.
Parry’s assessment threatened to undermine Monsanto’s narrative that glyphosate is not genotoxic. But as inconvenient as Parry’s assessment was, just ignoring it could get them into trouble. “I am concerned about leaving Perry [sic] out there with this as the final project/his final impressions,” responds one employee. Another later laments: “Mark [a Monsanto employee] was not managing that well and that almost landed us with Parry calling glyphosate ‘genotoxic.’”
Monsanto’s science influences the EPA’s cancer assessment of glyphosate
The unsealed documents underscore why relying on industry-funded data to assess the safety of pesticides puts public health at risk. Unfortunately, EPA’s 2016 cancer assessment for glyphosate overwhelming relied on unpublished industry studies. It also gave significant weight to the 2013 Kier and Kirkland study. This is resulted in an EPA assessment that proposed the lowest possible cancer rating for glyphosate: “not likely to be carcinogenic to humans.”
Notably, the agency’s Scientific Advisory Panel review of the EPA assessment shows disagreement over this conclusion. Some panel members support a classification of “suggestive evidence of carcinogenic potential.” And overall the panel agreed that EPA did not follow its own guidelines for undertaking cancer assessments.
Given the Scientific Advisory Panel’s evaluations—and the new evidence of Monsanto’s manipulation of science and collaboration with the EPA official overseeing the assessment—the EPA must reject its finding that glyphosate does not cause cancer. The agency must suspend glyphosate use until it completes an unbiased assessment using independent, publicly-available studies.