The United States District Court of the Eastern District of North Carolina recently issued a ruling on several Daubert challenges to a plaintiff’s proposed medical and causation experts in the Yates case.

The court excluded plaintiff’s first causation expert’s testimony, in part, barring any testimony regarding the “each and every exposure” theory. The court noted various other jurisdictions' rejection of the theory on the grounds that it lacks sufficient support in facts or data. Additionally, the court found the expert’s sole academic support, one article specifically prepared for litigation, to be insufficient to satisfy the reliability threshold under Daubert.

The court then distinguished plaintiff’s expert pathologist’s opinion from the “each and every exposure” theory. Plaintiff's expert opinion addressed “special exposures,” for which “there is scientific evidence that the exposure increases the risk,” of developing mesothelioma. Further distancing himself from the “each and every exposure theory,” he opined that such special exposures were distinct from “trivial exposures,” which would present minimal exposures and that the “mere presence of asbestos fibers in lungs,” does not, in and of itself, “increase one’s risk of developing diffuse malignant mesothelioma.”

Nonetheless, the court excluded his opinion entirely because it was not based on sufficient facts or data, did not result from reliable principles and methods, and did not reliably apply those principles and methods to the facts of the case.

According to the proposed expert, generally hazardous levels of asbestos dust are equivalent to the levels that would be present in “visible dust” or would be equivalent to the “types [of exposures] that have been proven by scientific evidence in their accumulation” to cause mesothelioma. This opinion was flawed because “visible dust,” as an increased risk factor, did not rise to the required level of demonstrating that the levels of asbestos exposure were hazardous nor did it account for varying degrees of hazards between different fiber types.

The court found that none of the literature established any qualitative or quantitative level of exposure from which asbestos becomes hazardous. Moreover, his selective use of articles, without acknowledging other relevant, contrary authority, called the methodology of his opinion into question. The court then rejected plaintiff’s counterargument—that the defendants’ use of epidemiological studies, some of which were funded by certain defendants was in error—because the plaintiff failed to demonstrate that the methodology used in these studies was biased or flawed.

Finally, the court noted that plaintiff's expert failed to apply his academic support to the specific facts in the plaintiff’s case. For example, he failed to comport his use of epidemiological studies regarding brake mechanics with the plaintiff’s testimony that he occasionally performed his own brake changes.  Additionally, the court found his misuse of the “Helsinki Criteria,” as evidence of causation concerning because its intended purpose is the demonstration of whether mesothelioma could be attributed to asbestos generally, and not for specifically evaluating “occupational, domestic, or environmental exposures.”