10th Circuit Upholds Exclusion of Fire Experts' "Pyrolysis" Opinions

The Tenth Circuit has published an opinion upholding the exclusion of testimony from multiple plaintiffs' experts who opined that a fire originated because a defective fluorescent light ballast heated the surrounding wood to a temperature of approximately 300 degrees Fahrenheit. The experts relied on a theory known as "pyrolysis," which posits that wood can catch fire at temperatures well under the usual 400 degrees, if exposed to a heat source over a lengthy period. The district court concluded that the pyrolysis hypothesis had not been subject to adequate testing for its reliability to be established in the scientific community. It also found that even if the pyrolysis theory was valid, it had not been reliably applied to the facts of the case.

Defendants did not mount a frontal assault on the concept of pyrolysis at the district court level, and in fact they arguably conceded it, but the Tenth Circuit panel said:

"[T]he district court's gatekeeper role requires it to examine the basis for challenged expert testimony to determine its reliability looking beyond the testimony of the witnesses before it to the scientific foundation for that testimony."

Read literally, that statement would seem to imply that even if every expert witness in an adversary proceeding agrees on the validity of a scientific principle, the district court is affirmatively required to evaluate the principle for itself. But the panel's opinion does rest in part on other evidentiary shortcomings that would have permitted the district court to exclude the evidence in its sound discretion. See Truck Ins. Exchange v. Magnetek, Inc., No. 03-1026 (10th Cir. Feb. 25, 2004) (Ebel, Briscoe, & Tymkovich, JJ.).