Inside Monsanto's Day in Court: Scientists Weigh in on Glyphosate's Cancer Risks | Civil Eats

Inside Monsanto’s Day in Court: Scientists Weigh in on Glyphosate’s Cancer Risks

U.N. cancer scientists and Monsanto experts face off over the science surrounding the world’s most widely used herbicide.

Roundup for residential use. (Photo credit: David Mulder.)

June 24, 2020 update: Bayer has agreed to pay $10 billion to settle tens of thousands of cases in the United States that claim glyphosate, the primary ingredient in its Roundup herbicide, caused cancer in people who sprayed the chemical or lived and worked near where the chemical was sprayed.

August 10, 2018 update: The jury in Lee Johnson’s trial awarded him $289.2 million in compensatory and punitive damages; Monsanto has said it plans to appeal the ruling.

June 10, 2018 update: U.S. District Judge Vince Chhabria allowed these trials to proceed to court, opening the door to hundreds of lawsuits against Monsanto and its new parent company, Bayer, arguing that exposure to weedkiller glyphosate caused their cancers.

Lee Johnson, a 46-year-old resident of Vallejo, California developed a severe skin rash in 2014, two years after he started spraying Roundup as part of his groundskeeping job at the Benicia Unified School District. “He read the label on the container,” says his lawyer, Timothy Litzenburg, “and he followed all the safety instructions, which were written by Monsanto.”

The rash turned into an aggressive form of non-Hodgkin lymphoma, a cancer of the lymphatic system. Doctors estimate Johnson has six months left to live; he will leave behind a wife and two children. His is one of 2,400 lawsuits filed against Monsanto by cancer victims in courts across the country, and Johnson’s case is the first one scheduled for a jury trial.

These victims are suing to hold Monsanto accountable, claiming that glyphosate, the listed, active ingredient in its popular herbicide Roundup, caused their non-Hodgkin lymphoma.

“About half of [our firm’s] cases are from people who sprayed Roundup for school districts or parks, while the others are from people who sprayed it around their homes,” Litzenburg said. Another law firm, representing around 600 plaintiffs, described their clients as consisting of roughly 60 percent residential glyphosate users, 10 percent school and park groundskeepers, and 30 percent orchard owners and farmers.

Plaintiffs are seeking monetary settlements in jury trials that could potentially amount to billions of dollars—settlements that could zero out the $2.8 billion in revenue Monsanto expects to make from Roundup this year alone. With more than 276 million pounds of glyphosate used in 2014 on farms, business, schools, parks and homes around the world, the stakes are high.

The lawsuits raise the question of whether the courts can accomplish what U.S. regulators have not: control or accountability over glyphosate, a chemical that international authorities in the U.N.’s top cancer group have deemed a probable carcinogen.

Earlier this month in San Francisco, U.S. District Judge Vince Chhabria began the process of determining whether or not scientific experts in these trials are using sound methods to reach their conclusions, and which experts can be called to the stand during upcoming federal trials.

Field test-spraying of glyphosate in Ghana. (Photo credit: Boasiedu)

Field test-spraying of glyphosate. (Photo credit: Boasiedu)

The 2,000 cases pending in state courts are not subject to Chhabria’s gatekeeping decisions and are already proceeding with the first case—Johnson’s—which is scheduled to begin in June.

To rule on the validity of the scientists and science, Chhabria heard from the 10 experts attorneys brought forward for the cancer-victim plaintiffs and for Monsanto in evidentiary hearings. He dubbed the Daubert hearings “Science Week,” and they served as his crash course on how world-class experts conduct cancer risk assessment.

“The judge’s role in a Daubert hearing is to find out if any of the evidence shouldn’t be presented to a jury because it lacks validity,” said Dr. Steven N. Goodman, an outside observer who is the Chief of Epidemiology for Health Research and Policy at Stanford School of Medicine. Dr. Goodman also been an instructor in judicial education courses on Daubert hearings.

Plaintiffs’ attorney Michael Baum agreed. “It’s supposed to keep ‘Ouiji board’ science out of the courtroom,” he said.

Good Data, Bad Data? IARC’s Experts vs. Monsanto’s Scientists

Daubert hearings permit both sides to present science, and in most cases, the lawyers present the scientists and studies that support their side of the argument. The scientists who testified under oath and on camera were experts in toxicology, animal studies, biostatistics, and epidemiology—all disciplines involved in cancer risk assessment.

The hearings marked the first time that Monsanto scientists faced off in court against three top scientists who had served on the U.N.’s International Agency for Research on Cancer (IARC), which in 2015 labeled glyphosate as a probable carcinogen. It was also the first time the three U.N. scientists had spoken in detail about the data and analysis underlying their decision.

Testifying for the plaintiffs, Dr. Charles William Jameson, an animal toxicology expert retired from the National Cancer Institute and the National Institutes of Health, explained how scientists work together to consider the totality of the evidence published in peer-reviewed studies. Animal studies come first. If rodent studies show evidence of carcinogenicity, scientists turn to studies of human populations to see if humans in the real world—at real-world exposure levels—are similarly affected.

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Jameson told the court that IARC benefited from what he said was an “extraordinarily high amount of animal study data” on glyphosate and that animal studies consistently showed that glyphosate causes cancer.

After listing a dozen studies showing replication of different cancers in mice and rats, Jameson concluded, “It is my opinion that exposure to glyphosate not only can cause non-Hodgkin lymphoma [in humans], but it is currently doing so, at current exposure levels today.”

Farm tractory spraying crops. (Photo credit: hpgruesen)

Farm tractory spraying crops. (Photo credit: hpgruesen)

Another of the plaintiffs’ expert witnesses, Dr. Chadi Nabhan, an oncologist and medical director for Cardinal Health in Chicago, testified to the conservative nature of IARC’s history of labeling compounds as carcinogenic.

First of all, Nabhan said, there are barriers to getting IARC to even undertake an analysis. “You have to prove that there is enough human exposure to get IARC’s interest, and that there’s enough animal data,” he said. Over IARC’s 53-year history, he said the group had considered 1,003 compounds and found only 20 percent of them to be either carcinogenic or probable carcinogens.

“I firmly believe in the conclusions of the IARC, and that actually makes a huge difference for us as clinicians,” Nabhan said, adding that he tells his patients not to use Roundup and glyphosate. “These are modifiable risk factors,” he said.

Monsanto has vigorously opposed IARC’s ruling, spending millions of dollars on a wide-ranging campaign to discredit these scientists as well as IARC itself, calling its methodology “junk science.”

Monsanto’s experts, who specialized in biostatistics, veterinary medicine, and prostate cancer, challenged the validity of the plaintiffs’ experts’ data and studies and presented their own views of the data as well as conflicting research.

Animal studies expert Dr. Thomas Rosol, an Ohio University veterinary medicine professor, for instance, challenged the widely held scientific concept of biological plausibility, which assumes a substance found to be carcinogenic in mice should also be presumed to cause cancer in humans, citing one instance where a new drug that caused cancer in mice did not cause cancer in humans.

Dr. Lorelei Mucci, an associate professor at Harvard whose research focuses on prostate cancer, relied heavily on a 2017 paper that analyzed data from a long-term study of 90,000 commercial pesticide applicators, farmers, and farmers’ spouses from Iowa and North Carolina and found no relationship between glyphosate exposure and cancer. The plaintiffs’ epidemiology experts, in response, highlighted the flaws they observed in that study, pointing instead to multiple studies that showed an association between glyphosate and an increased risk of getting non-Hodgkin lymphoma.

This kind of back-and-forth, with each side presenting data that supports its point of view, is common in Daubert hearings, said Stanford’s Goodman. “It’s very hard for a judge to understand in the adversarial context what are legitimate criticisms and what aren’t,” he said. “And then often what happens is minor or moderate disagreements or uncertainties are blown up or magnified to make the really big distinctions just seem like differing judgments.”

He added that, while scientists can “clearly tell the difference between reasonable scientific differences and unreasonable scientific differences,” judges often cannot. But, he cautioned, the judge’s role in such hearings is not to decide the case itself, but to allow a jury to hear from all of the expert scientists who meet professional standards.

What Comes Next

At the end of Science Week, Chhabria shared what he had learned from it—both as his first Daubert hearing as well as a crash course in cancer risk assessment. A week later, Chhabria invited two of the plaintiffs’ experts back for further questioning. While he felt confident that the science shows that glyphosate causes cancer in animals, he said, the epidemiological conclusions were not as clear.

“My biggest takeaway is that epidemiology is a loosey-goosey science and that it is highly subjective,” said Chhabria, adding that he found the population health study evidence on the plaintiffs’ side to be “pretty sparse.”

Chhabria said, “I have a difficult time understanding how an epidemiologist could conclude … that glyphosate is in fact causing non-Hodgkin lymphoma in human beings…. But I also question whether anyone could legitimately conclude that glyphosate is not causing non-Hodgkin lymphoma in human beings.”

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Whatever the judge’s beliefs may be, Chhabria noted that they are outside his purview within a Daubert hearing. “My role is to decide whether the opinions offered by the plaintiffs’ experts are within the range of reasonableness,” Chhabria said. “And the courts tell us that even a shaky opinion can be admissible because … that expert will then be subject to cross-examination. And the jury will get to hear all of the evidence, and decide who’s right and who’s wrong.“

Corn seed genetically engineered to withstand glyphosate spray. (Photo credit: <a href="">Orin Hargraves</a>)

Corn seed genetically engineered to withstand glyphosate spray. (Photo credit: Orin Hargraves)

Ricardo Salvador, a senior scientist and director of the Food and Environment Program at the Union of Concerned Scientists, said it’s hard for a non-scientist to assess the validity of epidemiological studies. “I think that epidemiology is being held to standards here that it cannot possibly meet because it’s an observational science,” he told Civil Eats. “The precision of the measurements are not going to be like controlled studies and lab bench work.”

Epidemiology, he explained, “is the tool that we have to detect signals at the population level. And when then a signal turns out to be something like non-Hodgkin lymphoma, there’s a public interest reason why we should pursue potential triggers or causes of that sort of epidemiology.”

Stanford’s Goodman notes that Daubert hearings require a judge to be willing to do “a lot of reading and homework outside the courtroom.” Since so much of what is said in the court is part of the arguments, he added, “The lawyers can always make little disagreements sound big, and sometimes big disagreements sound small.”

For instance, at the end of the oral arguments, Monsanto’s attorneys summed up the proceedings and told the judge that the plaintiffs’ experts had not used adjusted odds ratios in some of their calculations. The plaintiffs’ attorneys countered by citing the precise instances where their experts had used the proper methodology.

The tactic illustrates what Goodman says is one often used in Daubert hearings. “If a judge is not anchored by something outside of what he hears in the courtroom,” he said, “it’s going to be very hard—they’re trying to throw sand in his eyes. And it’s very, very difficult to see.”

Meanwhile, Michael Baum, an attorney for some of the plaintiffs, said that the Monsanto Papers—emails and internal memos received from Monsanto as part of the discovery process of these trials, and which revealed the company’s efforts to discredit IARC and mainstream science—had already made waves elsewhere in the world.

“It’s like the Wizard of Oz,” Baum said. “When you pull back the curtain, and when we sent all this evidence to E.U. decision makers, regulators, and legislators, they started seeing they’ve been fooled. Decision makers are starting to make different decisions.”

The E.U. voted in 2017 to limit glyphosate’s license renewal for a period of only five years, and many European countries have announced plans to end its use within three years. “Countries like France and Italy and Austria are saying … ‘we’re not waiting three to five years, we’re moving as soon as there is a viable alternative,’” Baum added.

Salvador cautioned that the process works differently in the U.S. In Europe, “the default is to be precautionary, so that the interest of the public, and public well-being and health are paramount,” he said. “In the United States, the worldview is that the interests of industry and their right to make a profit are dominant … which is very convenient for folks that profit from spewing chemicals into the environment.”

Chhabria last week scheduled followup hearings April 4-6 for more in-depth questioning of two of the plaintiff’s experts on their epidemiological conclusions. He is expected to rule in May about scientific evidence and experts permissible in federal cases. Meanwhile, lawsuits against Monsanto in state courts are set to start in June.

Pam Strayer is a California-based specialist on organic and biodynamic wines and an environmental journalist. Read more >

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  1. Tont Davies
    You failed to mention that the main Plaintiff expert was a university professor who was heavily quizzed by the judge and defendant attorney for why she contradicted her our deposition testimony and that she didn't use scientific methods to assess the risk. For example she ignored the data that said there was no cancer effect and she said she likes to analyze the data many different ways to find an effect. This is not sound science. There are an infinite number of ways to analyze data and if it shows an effect that is not statistically significant it is not real.
    • pam strayer

      First of all, because you refer to the "main Plaintiff expert" as a "she," I guess you are referring to Dr. Beatrice Ritz, from UCLA, who was the only woman expert for the plaintiffs. (The other woman expert -Dr. Lorele Mucci - testified for the defendants.

      I'd love to hear more about your scientific interests, but since a Google search of your name only brings up an anti-organic comment on a website from a few years ago, it's hard to know who you really are excpet that you have a lot of comments on your Disqus ID. So it would be great to know more about your degrees and your studies that have led you to the conclusions you've posted - i.e. "she didn't use scientific methods to assess the risk." That is a serious accusation to make and one that is hard to understand given that Dr. Ritz is a leading authority in her field.

      You may disagree with her conclusions, but she has based them on sound science. Scientists often debate, which is a process that leads them to explore the data in greater depth. Scientific debate is a valuable pursuit.

      Here is Dr. Ritz's professional profile from the UCLA web site:

      I wonder why you would choose to single out Dr. Ritz from the other experts among the five days of testimony. Perhaps you can share more about what in particular you disagreed with in her testimony.
    • How can anyone comment on or before March 30, 2018 . None of those opinions are fit because none have stated any basis for them and those study opinions stated no basis in 1st instance . Ritz has ignored my inquiry of her .
  2. Mary Mangan
    I was kind of impressed with the judge when reading his comments on the hearing. He was definitely attentive and sharp. But I think you missed one of the key things he said.

    "The Court [Judge Chhabria]: Does the IARC's conclusion that glyphosate is a probably carcinogen, you know, get the plaintiffs where they need to go?
    Answer: No."

    So I think that's a problem for people who thought they were gonna coast on the IARC.
    • pam strayer

      The judge's comments on IARC are very curious. Again, he is not called upon in this situation to evaluate the outcome of the case and the various strengths and weaknesses of the attorneys' arguments posed by both sides. He may however express an opinion but it is not his role to decide the cases. He is a gatekeeper for the scientific evidence, but it does not necessarily mean that the IARC ruling will not inform juries. All of the evidence underlying the IARC scientists' study and evaluation remains and each IARC expert looked at that data and evidence long before the IARC meeting was convened and came to their own conclusions.

      As the judge says, it is his job to rule on, "whether the opinions offered by the plaintiffs’ experts are within the range of reasonableness."
    • Mary Mangan

      I'm familiar with the science. And when the IARC report came out, I know a lot of scientists were perplexed at how they managed to avoid relevant studies and misuse other ones.

      What I'm saying is that people outside the glyphohate litigation bubble are finally running into people who are not buying the unfounded claims and handwaving. In the echo chamber it sounds good as y'all slap each other on the back, but when people take an actual look at the weakness of the IARC conclusions it unravels. It's clear they thought they could coast on IARC, and that's not the way it's working out.
    • Merle Noll
      Mary sounds like she works for Monsanto or their legal team. Which is it?
  3. Chrystal Hewitt
    is Round-up the reason wild life is dying off at alarming rates. Things did start dying off around the same time Round-up was introduced. Could the court, prosecute Monsanto's board of directors, or anyone at the company, if the courts finds they knew round-up caused cancer produced and sold it anyway?
    • Merle Noll
      Yes, to all.
  4. Brian Hayes
    You fail to mention that the IARC is the only agency to find a cancer risk with glyphosate, and that their process in making that finding is under question from many sources for being neither open, transparent, nor scientifically sound. In fact there is evidence of potential fraud. Failure to report on the controversy on the IARC finding is a failure of journalistic responsibility.
    • pam strayer

      IARC is not the only agency to find a cancer risk for non-Hodgkin lymphoma. The EPA did so in 1983 and numerous studies since then have also found links between Roundup and glyphosate and NHL The animal studies are incontrovertible, and no agency has disputed them.

      IARC is one of many scientific groups, but IARC is the gold standard. It is removed from the politics that regulators are subjected to. The three IARC members from the U.S. who testified are all former heads of U.S. government health agencies with credentials that are impeccable.

      In addition to IARC, more than 166 scientists signed a consensus agreement in the Journal of Epidemiology and Community Health attesting to the soundness of the IARC classification, which you can find here:

      "The IARC WG carefully and thoroughly evaluated all available epidemiology data, considering the strengths and weaknesses of each study. This is key to determining that the positive associations seen in the case–control studies are a reliable indication of an association and not simply due to chance or methodological flaws. To provide a reasonable interpretation of the findings, an evaluation needs to properly weight studies according to quality rather than simply count the number of positives and negatives. The two meta-analyses cited in the IARC Monograph11 are excellent examples of objective evaluations and show a consistent positive association between glyphosate and NHL."

      In Europe, top scientists have questioned EFSA's failure to see the link. They say EFSA did not follow EFSA's own guidelines. You can find this 2018 article published in the same scientific journal Journal of Epidemiology and Community Health here:

      "....[EFSA] not classifying glyphosate as a carcinogen by the European authorities, including the European Chemicals Agency, appears to be not consistent with, and in some instances, a direct violation of the applicable guidance and guideline documents...proper application of statistical methods and WoE criteria inevitably leads to the conclusion that glyphosate is ‘probably carcinogenic’ (corresponding to category 1B in the European Union)."

      I hope you will read these papers and learn more about the breadth of evidence.
  5. Karen Leclaire
    Epidemiology, while constantly pointed out as hearsay evidence, is the only basis to start investigations.

    If we do not notice trends and begin to investigate what the causality is of those trends, we bypass all aspects of science that have allowed us to advance in medicine and technology over the last one thousand years.

    Epidemiology is the beginning of the search for truth.
    • pam strayer
      Well said!
  6. Howard Stone
    Great article, well written and full of relevant content.
    May the great Monsanto fall and organics working with the earth rise.
    Thanks for the update...
    H Stone, New Zealand
  7. Linda Chapley
    Great information about the background and challenges ahead. With such widespread use on yards, public spaces and food, we’re all affected and should have more articles like this. Thank you for publishing.
  8. Dennis blake
    Worked for the parks Department of a fairly large city sprayed gallons of this stuff Round Up, once my Backpack sprayer sprung a leak Round up went down our back down or butt Developed a rash so far no Ill affects thank God.
    • Merle Noll
      Get a biopsy. The rash is the Cancer.
  9. Merle Noll
    They got's to pay!
    • Merle Noll ,proof is in what happened to blood of all 8000 plaintiff's , and now there are 150 more plaintiff's that could be asked and who could answer what their diagnosis IgM was , we have not yet heard what Dewayne Lee Johnson's diagnosis IgM was , and it should be telling ! Dewayne Lee Johnson's exposure seems to have been an average consecutive 2.5 days per week, which was less than my 7 days .
  10. Asrael
    What’s Right is Right!
    Our Earth is NOT Going to be mismanaged as they employ GREED. This is a subtle from of chemical warfare. Knowing you are causing death thru sickness is STILL
    murder! How Pleasant could Your Dreams Be Monsanto? We All are Subject to the Supreme Court! How will YOU be Judged? The Pope should read Psalms 37 to the World or would He Also be KILLED!
    “He is going to bring to ruin those ruining the Earth!” Revelation 11:18 It is TOO LATE for EVIL!
  11. Matthew Churney
    Monsanto has people in every area of government influencing policy, because if they didn't, their known history of producing poisons like Agent Orange & DDT & other nefarious products like Roundup would weigh in on removing their role in tainting our food supplies. The fact that President Obama appointed a former Monsanto employee to head up the FDA is conclusive proof of complicity & conflict of interest between corporations & government. This alone should be enough of a cautionary aside to allow for judgment in favor of the plaintiffs & for banning glysophate from use & marching Monsanto moles out of all corners of government.
  12. Wendu
    Thank you for putting this info out there!!! People need to wake up and be aware of what is happening to our beautiful environment, and our health!!
    • BOB W
      Some us people out here know whats going on with our environment!! Dow and Monsanto know also however they are blinded by $$ they want it for their pockets saying nothing is wrong with roundup, believe that one I'll sell you the Brooklyn Bridge!! Our dept of defence (dod) belived them during Bietnam both companies said: It wont harm the troops in the field" guess what -- Wrong !!!!
  13. Aaron
    Great article. thank you
  14. BOB W
    it sounds as if this glyphosate is a "relative" of agent orange giving cancer to people that use "roundup" even after reading all the directions and wearing safety clothing /equipment this sounds very familiar with Monsanto having their hands in a "weed killer"
  15. I have been trying for 7 months to reveal truth about how Roundup causes NHL , and no one is listening . Most of these study scientists have been getting more and more stupid ! NHL is not caused by glyphosate unless polyethoxylated tallow amine is an aide to glyphosate , and it could be because P.O.E.A -15 is many more times toxic than glyphosate alone , says Ceralinii , who because he is a biologist , he can not discuss how what happens to blood is what proves Roundup caused my Waldenstrom Macroglobulinemia .
  16. Dr. John Gardiner
    Salvador's comments in the penultimate paragraph expose the underlying difference between the EU's precautionary approach that protects its citizens, and the US approach that emphasizes industry and 'profit' that externalizes the social and environmental costs. The EU tries for all-round sustainability and the US does not, which is why the world is doomed unless the EU approach prevails somehow. It's now clear to anyone who has an open mind that the corporate for-profit game is over
  17. A really useful review of the science behind the decision. Article could have been more explicit about the democratic function of juries, which has led to their historic role in upending many incorrect rules by governments.

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