Glyphosate and Non-Hodgkin’s Lymphoma Claims: Different Results In Different Courtrooms Based On The Same Science

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We recently reported on a $289 million verdict for plaintiff Dewayne Johnson against Monsanto Company in the state Superior Court of California, an astounding verdict by the jury who found that Mr. Johnson’s use of glyphosate-containing herbicides caused him to develop a type of cancer known as non-Hodgkin’s lymphoma. Monsanto will be appealing the verdict on the grounds that the science does not show that glyphosate causes cancer. While the court in Johnson admitted scientific evidence by plaintiffs that glyphosate causes cancer, it is not necessarily the case that other courts will do the same.

The determination of what scientific evidence is admitted for a jury to hear, however, comes down to the particular standard of admissibility that a court follows.

First, what does the science say?

There are numerous studies on whether glyphosate is a carcinogen. The Environmental Protection Agency has stated that glyphosate is not likely to cause cancer or other significant risks to human health. The European Food Safety Authority, an agency of the European Union, has come to a similar conclusion. However, in 2015, the World Health Organization’s (WHO) International Agency for Research on Cancer found that glyphosate is “probably carcinogenic to humans.” This is one of the studies that plaintiff’s counsel relied upon in the Johnson case mentioned above. But, in May 2016, a group of pesticide residue experts at WHO and the United Nations concluded that glyphosate is “unlikely to pose a carcinogenic risk to humans.” WHO explained that the 2015 and 2016 findings are not contradictory because the 2015 study evaluated the potential for cancer without taking into account the actual risk of being exposed to glyphosate; the 2016 study assessed the actual risk of cancer posed to humans from dietary exposure to glyphosate residues in food. Other studies contain their own nuanced findings and conclusions.

What’s the standard of admissibility?

There are two main standards of admissibility that courts follow: the Daubert and Frye standards. The Daubert standard is generally considered the more stringent of the two standards and is the law in federal court and over half of the states. The Johnson case, mentioned above, followed the Frye standard and plaintiffs’ experts’ testimony was admitted.

We recently saw, however, that in a jurisdiction that follows the Daubert standard, the federal judge expressed skepticism at the scientific evidence offered by plaintiffs: U.S. District Court Judge Vince Chhabria of the Northern District of California, who is presiding over more than 400 glyphosate cases (Roundup Prods. Liab. Litig.), stated that plaintiffs’ experts’ evidence regarding glyphosate’s ability to cause non-Hodgkin’s lymphoma was “rather weak.” He excluded some experts, and while he allowed the opinions of other experts, he described those opinions as “shaky.” While the judge did not go so far as to say that plaintiffs’ experts were engaging in “junk science,” he warned that it could be a “daunting challenge” to persuade him to allow a jury to hear testimony that glyphosate was responsible for the cancer diagnoses of individual plaintiffs.

On the basis of these recent decisions and the expected appeal in Johnson, it remains to be seen how courts in various jurisdictions will rule on the science. Currently, over 8,000 other lawsuits alleging harm by glyphosate are pending in state and federal courts across the country. Notably, state lawsuits filed in St. Louis are scheduled to go to trial in 2019.

We’ll monitor and report back what we anticipate will likely be extremely divergent results on courts’ rulings of admissibility of expert opinions relating to glyphosate.