Plaintiff Expert Must Exclude Other Plausible Causation Theories

In an interesting products/fire case, the Texas Supreme Court confirmed last week that a plaintiff's expert must explain or disprove alternative causation theories to establish plaintiff's causation theory. See Wal-Mart Stores Inc. v. MerrellNo. 09-0224  (Tex. 6/18/10).

Plaintiffs' decedents died from smoke inhalation in the bedroom of their rented home. When police officers arrived, they found in the living room a badly burned recliner, a damaged pole-style floor lamp, and other furniture covered in soot and smoke. There were candles, melted wax, an ashtray, and smoking paraphernalia throughout the house, including ash trays, a "bong," and marijuana cigarette butts. The fire marshal declared the fire accidental and of unknown origin. Then, plaintiffs brought wrongful death and survival claims against Wal-Mart, alleging that a halogen lamp in the apartment, purchased from Wal-Mart, caused the fire.

Merrell’s expert, Dr. Beyler, attributed the fire to “nonpassive failure" of the lamp igniting the recliner below it.  He opined that the lamp’s halogen bulb exploded, sending burning glass shards onto the recliner, which smoldered for several hours. Beyer admitted there were possible other mechanisms.  But he purported to rule out smoking materials as the cause because none
were found in the immediate “area of origin” of the fire. He also purported to rule out the candles as the cause of the fire because, had the candles been the source of ignition, the candle wax on the
table allegedly would not have survived the exposure.

Wal-Mart’s expert, John Lentini, testified that the more likely cause of this fire was careless disposal of smoking materials.

Wal-Mart contended on appeal that even if Beyler’s testimony was properly admitted, it constituted no evidence of causation because his opinion lacked factual substantiation and therefor was too
conclusory.  Specifically, Wal-Mart contended that Beyler’s testimony did not show that the lamp was more likely to have caused the fire than any other obvious potential sources.

The general rule here is that opinion testimony that is conclusory or speculative is not relevant evidence, because it does not tend to make the existence of a material fact more probable
or less probable. Such conclusory statements cannot support a judgment. 

The Court conducted a careful review of the record, reminding readers how important the details, nuances, language of expert reports and testimony can be, especially in close cases. While much attention is given to the support the expert has for the chosen theory, equal attention should be given to the expert's attempt to rule out other possible mechanisms.

The Court concluded that Beyler did not really answer why a burning cigarette could not have caused the fire. He dismissed as irrelevant the fact that post-mortem toxicology reports revealed that the decedents had been smoking the very night of the fire because, according to Beyler, that
evidence did not provide data relevant to the investigation of causes available in the area of
origin.  But, relating to the recliner, it was unexplained why not having found evidence of burnt cigarettes right there was significant when there was likewise no evidence of charred or exploded glass either in the recliner or anywhere else in the house -- which was his adopted theory. So, while Beyler did undertake to eliminate one potential cause of the fire that might otherwise seem on a par with the lamp theory, the melted candle wax, he provided no coherent explanation for why lit smoking materials could not have been the source.

An expert’s failure to explain or adequately disprove alternative theories of causation makes his or her own theory speculative and conclusory. See Gen. Motors Corp. v. Iracheta, 161 S.W.3d 462, 470 (Tex. 2005) (expert eliminated the obvious possibility that fuel or vapors from the tank filler neck ignited only by saying so, offering no other basis for his opinion. Such a bare opinion was not
enough.).

Causation opinion insufficient. Judgment for defendant.