Caution: just because you perform some tests, you are not necessarily out of the woods. The Werth v. Hill-Rom, Inc. case, where over a million dollars in testing was performed, is illustrative of this fact. 2012 WL 1379660 (D. Minn. April 18, 2012). A hospital and the parents of a newborn filed suit against the manufacturer of a baby warmer. The baby suffered from a respiratory condition and had been placed under an oxygen hood and laid in a bassinet under a baby warmer immediately after birth.

While a nurse was checking his vital signs, she leaned toward him with a stethoscope and a fire erupted in the bassinet. The flames were quickly extinguished but not before the baby suffered severe burns.

Immediately after the fire, the hospital assembled a team of five experts to investigate the fire’s cause. Records disclosed that the manufacturer’s baby warmers, including the type at issue here, were recalled in the early 1990’s. In several instances, hot particles were noted to have fallen from the heating element into the bassinet below. The manufacturer modified the design to include protective end covers, intended to catch particles that might break off, and since that time no similar incidents have been reported. The modified end cap covers had in fact been installed on the baby warmer at issue.

The team of experts developed several hypotheses as to the cause of the fire and performed extensive testing and analyses to determine which of the hypotheses they believed was the “most likely” cause. 

Each of the tests successfully eliminated one of the potential hypotheses. Based on these tests, some heat transfer calculations, and the exclusion of other hypothesis for the fire’s origin, the experts opined that “ignition due to a hot [quartz] particle originating from the…warmer heater assembly and falling into the bassinet is the most likely ignition source for the…incident.” Two reports were prepared. The initial report opined only that a hot quartz particle “is the most likely ignition source” for the incident.

The supplemental report opined to a reasonable degree of scientific and engineering certainty, that the fire “actually was caused by . . . a hot particle originating from the warmer heater element assembly falling into the bassinet and igniting the oxygen–enriched solid combustibles.” The supplemental report nowhere explained why it contained a more authoritative opinion on the fire’s cause than the initial report and contained no discussion of additional testing or analysis performed following the initial report preparation.

Plaintiffs filed suit against the manufacturer based upon these opinions. The manufacturer moved to exclude the expert opinions, arguing that the causation theory is untested speculation in that the experts failed to test their theory to show (1) how a particle could break from a quartz tube, and (2) how such a particle could exit the end cap, avoid the end cover and travel to the bassinet.

The court found that plaintiff’s expert did not reliably apply NFPA 921 to the facts of the case. “A key step under NFPA 921, once an investigator has developed a hypothesis about a fire’s cause, is testing that hypotheses.” Yet, according to the court, nothing in either reports indicated that the experts tested their hypotheses at all. Note the experts performed over a million dollars’ worth of tests. However, these tests were to rule out certain hypotheses; the experts failed to physically test the theory they ruled in. “Such testing was critical because NFPA 921 requires an investigator to determine (1) ‘the circumstances that brought the ignition source [the quartz chip] in contact with the first fuel ignited [the bassinet materials],’ . . . and (2) ‘[h]ow safety devices and features designed to prevent fire from occurring [the end cap and end cover] failed to operate.’” The report simply described ways in which a chip could have broken free of a quartz tube and made its way to the bassinet. 

Such speculation is simply not enough and, notably, NFPA 921 itself provides that “speculative information cannot be included” in a fire cause analysis. Though the supplemental report was stronger in its conclusion, nowhere did it explain why it contained a more definitive opinion, which is practically problematic given that the supplemental report simply adopted and incorporated the initial report reasoning.  Without any evidence or other explanation for the greater level of confidence, the court concluded that the supplementary report was contrary to NFPA 921 and nothing more than the experts’ litigation say so.

Finally, the court noted that exemplar warmers were available to the experts and that such testing could have been performed. The absence of physical tests stood in stark contrast to the extensive testing the experts did undertake with regard to other potential causes for the fire. The experts’ failure to physically test their hypotheses undermined the reliability of their opinion and rendered it too speculative to admit. Further, the court rejected plaintiffs’ contention that the experts’ “cognitive testing” – or “thought experiments” – was sufficient under to NFPA 921§4.3.6.

Though cognitive testing is permitted under NFPA 921, courts have recognized that physical testing plays an important role in validating a theory under 921 even if such testing is not required. Such testing was particularly important given that the experts’ causation theory apparently had not occurred since the manufacturer modified the warmer’s design and the lack of published studies or other literature substantiating the experts’ theory. The court excluded the experts’ testimony and precluded them from opining at trial.