Tager_09181Featured Expert Column: Judicial Gatekeeping of Expert Evidence

By Evan M. Tager, Mayer Brown LLP, with Carl J. Summers, Mayer Brown LLP

Plaintiffs in asbestos cases often maintain that every asbestos exposure above background level is a substantial contributing factor to mesothelioma. That theory has been roundly rejected by courts. In a recent opinion, an intermediate appellate court in Florida joined the chorus of decisions refusing to credit the “every exposure above background level” theory.

In Crane Co. v. DeLisle, 2016 WL 4771438 (Fla. Dist. Ct. App. Sept. 14, 2016), the plaintiff developed mesothelioma after allegedly working around “Cranite” sheet gaskets containing chrysotile asbestos fibers and smoking asbestos-containing cigarettes in the 1950s. Following a trial involving multiple defendants, a jury awarded the plaintiff $8 million in damages. The Florida District Court of Appeal, however, reversed and remanded for entry of a directed verdict in favor of Crane Co., the manufacturer of the sheet gaskets, and a new trial for R.J. Reynolds, the cigarette manufacturer.

The plaintiff’s sole expert testimony concerning the chrysotile asbestos-containing sheet gaskets came from Dr. James Dahlgren, a medical doctor who specializes in toxicology. In determining whether a particular substance caused the plaintiff’s mesothelioma, Dr. Dahlgren purported to rely on the so-called Bradford Hill criteria: strength, consistency, specificity, temporality, biological gradient, plausibility, coherence, experiment, and analogy. Dr. Dahlgren, however, did not explain what the Bradford Hill criteria mean or how he used them to analyze causation.

In addition, Dr. Dahlgren did not personally conduct any studies to determine the amount of asbestos that can cause mesothelioma. Instead, Dr. Dahlgren reviewed the scientific literature. When asked whether all commercial types of asbestos were similarly potent, Dr. Dahlgren responded “probably,” though he acknowledged that human pathology studies indicate that exposure to chrysotile fibers is not equivalent to exposure to other forms of asbestos. Dr. Dahlgren dismissed the human studies, however, and instead claimed that he was relying on animal studies (which he did not provide or explain) and a South African study that actually involved crocidolite asbestos, not chrysotile asbestos.

Of particular importance here, Dr. Dahlgren testified that every exposure to asbestos of any kind above background level is a substantial contributing cause of mesothelioma. He failed, however, to identify any study that supports this theory. Dr. Dahlgren further testified that he did not think that such a study could be performed.

Declaring that a “trial court’s gatekeeping role is not a passive role,” the Florida DCA held that Dr. Dahlgren’s expert opinion was not supported by sufficient data in the record or based upon reliable principles and methods as required by Daubert. The court cited Dr. Dahlgren’s failure to explain both the Bradford Hill criteria and his application of them to the plaintiff’s illness. Notably, it pointed out that the Bradford Hill criteria generally do not support a causation opinion without controlled epidemiological studies demonstrating a correlation between exposures similar to the plaintiff’s and the plaintiff’s disease. The DCA also faulted Dr. Dahlgren for drawing conclusions about the causal role of chrysotile asbestos from studies that involved mixed-asbestos exposures (both chrysotile and amphibole).

As to Dr. Dahlgren’s ultimate conclusion that every exposure to asbestos above background level is a substantial contributing factor, the court noted that this theory “has been rejected repeatedly by courts as insufficiently supported by data or testing to satisfy Daubert.” Collecting several cases that rejected this theory, the court explained that the judicial reception to this theory has been “largely negative.” The court went on to state that Dr. Dahlgren’s theory “is not supported by any studies, as it has not been tested” and that other experts testifying for the plaintiff rejected Dr. Dahlgren’s theory. In the end, the court characterized Dr. Dahlgren’s testimony as mere ipse dixit, explaining that he was claiming that his testimony was “reliable merely because he is an expert.” Such testimony, the court explained, does not satisfy the strictures of Daubert. Because Dr. Dalhgren’s testimony was the sole evidence of causation linking the plaintiff’s mesothelioma to his exposure to Crane’s chrysotile asbestos-containing products, the court ordered that a directed verdict be entered in Crane’s favor.

The court’s decision in Crane demonstrates the paucity of support for the “every exposure above background level” theory of causation in asbestos cases. Plaintiff’s attorneys in asbestos cases have attempted to circumvent the requirements of specific causation by relying on experts who claim that any exposure to asbestos can be a substantial contributing factor to mesothelioma or lung cancer. Such theories are closer to junk science than actual science. Indeed, as the court in this case aptly stated, there are no studies demonstrating that any exposure to asbestos above background level causes mesothelioma or lung cancer.