Deferring to the role of a jury in resolving questions of competing scientific theories, a California appeals court upheld a trial court’s ruling allowing expert testimony based on the “every exposure” theory, calling it “the subject of legitimate scientific debate.”  See Davis v. Honeywell Int’l Inc., 199 Cal.Rptr.3d 583 (Cal. Ct. App. 2016).

Plaintiff brought suit for wrongful death and negligence, among other claims, alleging decedent’s exposure to asbestos in Defendant’s brake linings during the 1960s and 70s contributed to his development of mesothelioma and subsequent death.  After the trial court allowed expert testimony on the “every exposure” theory, which states that even low doses of asbestos are substantial factors contributing to the aggregate dose of asbestos that causes mesothelioma, a jury found for Plaintiff and awarded $2 million in damages.

Defendant appealed, arguing that the expert testimony relying on the every exposure theory should have been excluded as speculative and devoid of evidentiary and logical support.  In upholding the trial court’s decision to allow the testimony, the Court held that although the trial court has a duty to act as a “gatekeeper” in excluding “clearly invalid and unreliable” expert opinion, its role is not to choose between expert opinions.  Id. at 590. The Court found that the theory could be reconciled with the defense expert’s opinion that mesothelioma and other asbestos-related diseases are dose dependent.  Therefore it was up to the jury, not the judge, to decide which opinion to apply.

This article was written with the assistance of Brooklyn N. Hildebrandt.