Contains Asbestos Causation Warning Sign Plaintiff smoked a pack and a half of cigarettes every day for 30 years and suffered from lung cancer. He also worked aboard navy vessels removing insulation, which he claimed exposed him to asbestos fibers. Plus, for two weeks, he worked as an independent contractor at Defendant’s refinery replacing heaters that Plaintiff claimed were insulated with asbestos.

The refinery presented counter-evidence that the insulation at its refinery didn’t contain asbestos. Nevertheless, Plaintiff’s position was that Defendant Insulation Manufacturer and Defendant Refinery exposed him to asbestos which was a substantial cause of his lung cancer.

A jury found that cigarettes were the sole cause of Plaintiff’s cancer, but on appeal, he claimed that rulings by the district court deprived him of a fair trial. Plaintiff contended that the district court erred by excluding testimony about medical causation from his expert.

Prior to trial, the defendants filed motions before a judge in the Northern District of Illinois seeking to exclude Plaintiff’s causation expert and other witnesses from testifying about a theory of causation often referred to as “each and every exposure theory,” “any exposure theory,” “the single fiber theory,” or “no safe level of exposure theory” among others. These theories hold that any exposure to asbestos fibers whatsoever, regardless of the amount of fibers or length of exposure constitutes an underlying cause of injury to the exposed individual. The judge held that Plaintiff hadn’t established that the “any exposure” theory was sufficiently reliable to warrant admission under Rule 702 and Daubert. Plaintiff was precluded from offering any expert testimony espousing such a theory at trial. Plaintiff didn’t challenge that ruling through this appeal.

Before trial, the case was transferred to another judge. Despite the earlier Daubert ruling, Plaintiff called his causation expert at trial, hoping that a newly packaged “cumulative exposure theory” would skirt the earlier ruling on the motion in limine. During voir dire of Plaintiff’s causation expert, however, the second judge concluded that the expert’s testimony was still “not tied to the specific quantum of exposure attributable to the defendants, but was instead based on his medical and scientific opinion that every exposure is a substantial contributing factor to the cumulative exposure that causes cancer.”

The judge indicated that he was following the pre-trial determination of the prior judge and that the “cumulative exposure” testimony was no different than the testimony proffered in the earlier proceedings.

On appeal, U.S. Circuit Judge Ilana Kara Diamond Rovner of the U.S. Court of Appeals for the Seventh Circuit wrote in her opinion that the party seeking to introduce the expert witness testimony must show that the expert witness testimony satisfies the standard by a preponderance of the evidence. Plaintiff didn’t dispute that the district court identified and applied the appropriate Daubert framework, but argued that the second judge made an errant factual determination that the cumulative exposure theory was the same as the “each and every exposure” theory that the previous judge had barred.

The Seventh Circuit stated that in addition to Federal Rule of Evidence 702 and Daubert, Federal Rule of Evidence 403 overlays all other evidentiary rules by stating that a court may “exclude relevant evidence if its probative value is substantially outweighed by the danger of … unfair prejudice, confusing the issues, [or] misleading the jury.” Judge Rovner explained that the district court holds broad discretion in its gatekeeper function of determining the relevance and reliability of the expert opinion testimony, and that it may apply the Daubert factors flexibly as the case requires.

The first judge’s pre-trial motion concluded that under both Illinois law and maritime law, a plaintiff must show that asbestos was a “substantial contributing factor” to his injury. However, rather than testifying that the particular dose of asbestos to which Plaintiff had been exposed was a substantial contributing factor to his illness, the causation expert’s theory was based on a premise that each and every exposure to asbestos—including the first exposure—no matter how de minimis, “is a substantial contribution to the cumulative total.” Plaintiff’s causation expert further explained: “Either it’s zero or it’s substantial; there is no such thing as not substantial.”

Applying Daubert, the court concluded that the “any exposure” theory ignored fundamental principles of toxicology that illnesses like cancer are dose-dependent. Plaintiff’s expert didn’t plan to offer any evidence about how much asbestos exposure Plaintiff experienced and whether that dosage could have been a substantial contributing factor to lung cancer. The expert’s asserted theory was that any and all exposure to asbestos is a substantial contributing factor to lung cancer. The law of causation, however, required the plaintiff to prove that the defendants‘ acts or products were a “substantial contributing factor” to Plaintiff’s illness. De minimis exposure wasn’t sufficient, and substantial exposure that can’t be attributed to a particular defendant is likewise insufficient, Judge Rovner found.

The expert failed to present any individualized analysis of the level of asbestos exposure, provided only generalized citations to scientific literature with no indication that they were authorities upon which the experts would rely, didn’t identify any peer-reviewed scientific journal adopting this theory, didn’t cite any medical studies, and didn’t discuss an error rate.

Plaintiff failed to bear the burden of demonstrating that Plaintiff’s causation expert’s theory would satisfy the minimal requirements of Federal Rule of Evidence 702 and Daubert.

In light of the ruling barring the use of “each and every exposure” testimony, Plaintiff tried to repackage his causation expert’s testimony as being based on a “cumulative exposure” theory. But the second district court judge concluded that the “cumulative exposure” theory was just more of the same.

Judge Rovner held that causation requires that an expert connect the nature of the asbestos exposure and pair it with a Daubert-approved methodology that can be used to determine whether such an exposure was a substantial cause of the defendant’s injury. The second judge made clear that he was following the previous ruling when the earlier judge determined that both theories were the same for purposes of determining causation. As a result, the district court didn’t err and didn’t abuse its discretion by excluding this testimony.

The decision of the district court was affirmed.