Epidemiology Expert Witness Testimony Allowed in Products Liability Case

Summary: Epidemiology Expert Witness allowed to testify in products liability case despite arguments that she changed her testimony.

Facts:  This case (Barrera, et al. v. Monsanto Company  – Superior Court of the State of Delaware – May 31st, 2019) involves a products liability claim.  The plaintiffs allege that their cancer was caused by exposure to the defendant’s herbicide product, commonly known as Roundup.  The plaintiffs have hired Epidemiology Expert Witness Dr. Beate Ritz to provide testimony.  The defendant has filed a motion to exclude this expert from testifying.

Discussion:  Dr. Ritz is a professor of epidemiology at the UCLA Fielding School of Public Heath and holds a Ph.D in epidemiology and an MD.  Her research focuses on the health effects of environmental and occupational exposures.  The court notes that there is no dispute that Dr. Ritz is qualified to opine in the field of epidemiology in this case.

Dr. Ritz notes that Roundup is capable of causing NHL.  She reviewed a number of epidemiologic studies and examined how these studies worked together.

Dr. Ritz opined that a specificity criterion is not easy to apply in cases like these which involve pesticide or herbicide exposure because most of the people who work with these products are not exposed only to glyphosate.  Dr. Ritz opined that in terms of biological plausibility, this criterion was met.  In addition, Dr. Ritz relied on mechanistic evidence to support the biological plausibility that a casual connection between glyphosate and NHL exists.

Dr. Ritz also opines that the epidemiological studies support an increased risk of NHL with exposure to glyphosate or glyphosate based formulations, which includes Roundup.

The defendant argues that Dr. Ritz changed her opinion of the epidemiological evidence.  The court opines that this argument goes to the weight of the evidence, not its admissibility.

The court opines that Dr. Ritz’a opinion is relevant to general causation and whether glyphosate can cause NHL in humans at realistic levels. to which they are exposed.  The court further opines that the principles and methodology underlying Dr. Ritz’s opinion are valid and can be properly applied to this case.  The court also notes that Dr. Ritz relied on peer-reviewed studies and literature.

Conclusion:  The motion to exclude the expert witness opinion of Dr. Beate Ritz is denied.