On August 10th a California jury awarded Dewayne Johnson $289 million dollars in damages against the company Monsanto (now owned by Bayer). The decision was based on the claim that Johnson (a greenskeeper) developed non-Hodgkins lymphoma because of his exposure to Roundup, an herbicide that contains the active ingredient glyphosate that was developed by Monsanto.

The decision will almost certainly be appealed, and is being widely criticized because it is not in line with the science. There is a long history of juries awarded damages based on flimsy science. Dow Corning famously filed for bankruptcy following class action law suits for alleged damages due to silicone breast implants, while the science was still preliminary. The claim was that the breast implants were causing auto-immune disease, which the manufacturer denied. Juries found the women sympathetic, however, and companies rarely appear sympathetic in such trials. But in 2000 a meta-analysis found:

On the basis of our meta-analyses, there was no evidence of an association between breast implants in general, or silicone-gel-filled breast implants specifically, and any of the individual connective-tissue diseases, all definite connective-tissue diseases combined, or other autoimmune or rheumatic conditions. From a public health perspective, breast implants appear to have a minimal effect on the number of women in whom connective-tissue diseases develop, and the elimination of implants would not be likely to reduce the incidence of connective-tissue diseases.

It seems we have a similar situation with Roundup and cancer, except the meta-analysis was published before the huge jury award, rather than after. The wrinkle here is that this and other lawsuits were likely sparked in part by the WHO decision in 2015 to classify glyphosate as a “probable carcinogen”. That decision was an outlier, however, and was immediately criticized. Several independent reviews of the WHO decision concluded that the decision was in error, and that the totality of evidence does not support the conclusion that there is any link between glyphosate and non-Hodgkins lymphoma specifically, or any cancer. I review the evidence and the expert panel reviews here.

An interesting 2017 review explored why the European Union (which concluded glyphosate was safe) came to a different conclusion than the WHO:

Use of different data sets, particularly on long-term toxicity/carcinogenicity in rodents, could partially explain the divergent views; but methodological differences in the evaluation of the available evidence have been identified. The EU assessment did not identify a carcinogenicity hazard, revised the toxicological profile proposing new toxicological reference values, and conducted a risk assessment for some representatives uses.

Essentially they used different data and methods. There is also this:

In a Special Report published on June 14, 2017, investigators at Reuters uncovered the shocking fact that an American scientist, Dr. Aaron Blair, the Chairman of the International Agency for Research on Cancer’s (IARC) Monograph 112 on glyphosate, suppressed critically important science.

The hidden science in question is recent data from the Agricultural Health Study (AHS), the largest and most comprehensive study ever conducted on pesticide exposure in humans. Evidence shows that Dr. Blair withheld updated data from the study which evaluates the pesticide exposure of more than 50,000 farmers and their families. The updated data reinforces the study’s original conclusion in 2005 that there is no evidence linking glyphosate exposure to cancer incidence.

So the best data we have shows no link between glyphosate and cancer, but that data was ignored by Dr. Blair. Further, Blair was involved with this study, and so definitely knew this data existed. Also, under oath Dr. Blair admitted: “[the] data would have altered IARC’s analysis.”

We are now, in part, seeing the fallout from this bad decision by the IARC.

According to reports of the case, Johnson’s attorney had to overcome the actual science showing glyphosate is safe and not associated with cancer. He did this by claiming that Roundup as a whole may cause cancer, even though glyphosate alone does not. While not impossible, this is an implausible claim that is still lacking in evidence. This was an act of simply moving the goalpost to avoid the more definitive scientific evidence. The ploy worked.

Johnson is also claiming that he had two accidental exposed to Roundup, so he was exposed to far more than would be the case with normal use. However, the time between exposure and his development of NHL was probably far too short for a causal relationship – a fact apparently not considered compelling by the jury.

Why should we all care about this? I of course have sympathy for Mr. Johnson, just as I have sympathy for all of those women who developed autoimmune diseases after getting silicone breast implants. I also think it is extremely important to hold corporations accountable if they cause harm due to their products. But justice in these cases will only prevail if the science prevails.

Further, glyphosate is demonstrably far less toxic than the alternative herbicides. If glyphosate is banned, or rendered unusable because of unfair lawsuits and unscientific jury verdicts, an important agricultural option will be eliminated – not because of science or because it’s the right thing, but out of fear and ignorance.

Reasonable people can argue and disagree about the optimal role of glyphosate and other herbicides in agriculture, and that is not the point of this article. But agricultural decisions should be based on a consensus view of the science, not the emotions of 12 jurors who clearly wanted to punish Monsanto regardless of what the science says.

This and other decisions also point to a flaw in our legal system. This is a much longer discussion outside the scope of this article, but the rules on the admissibility and role of scientific evidence in the courtroom still leave much to be desired in my opinion. Ultimately this case turned on an evaluation of a scientific claim, and I don’t see why such scientific questions should be decided by non-expert jurors.


Posted by Steven Novella

Founder and currently Executive Editor of Science-Based Medicine Steven Novella, MD is an academic clinical neurologist at the Yale University School of Medicine. He is also the host and producer of the popular weekly science podcast, The Skeptics’ Guide to the Universe, and the author of the NeuroLogicaBlog, a daily blog that covers news and issues in neuroscience, but also general science, scientific skepticism, philosophy of science, critical thinking, and the intersection of science with the media and society. Dr. Novella also has produced two courses with The Great Courses, and published a book on critical thinking - also called The Skeptics Guide to the Universe.