How Likely is “More Likely Than Not”? Expert Testimony Under CERCLA

Those of us who litigate know that, with all respect to our expert colleagues, pulling a necessary opinion out of an expert can be very difficult. Experts like adjectives and adverbs, particularly if those modifiers help the expert avoid saying anything meaningful. A recent decision from the Court of Appeals for the Fourth Circuit makes clear the limits of such timidity.

In Miller v. Mandrin Homes, the plaintiffs alleged that the defendants sold them a house that was subject to contamination. The plaintiffs brought several claims, including one under CERCLA, which they admitted was the crux of the case. As our readers know, one of the elements of a prima facie case under CERCLA is proof that there has been a release or threatened release of a hazardous substance. 

Unfortunately for the plaintiffs’, their expert only stated that contamination detected in a sump at the house was “indicative” of a release. The court found such testimony speculative, stating that this phrase “does not show that [the expert] … could testify that it was his scientific opinion that groundwater contamination existed. [The expert] stated his opinion in a passive manner that suggests his finding falls in the realm of the possible rather than the probable.”

The lesson here is critical, if basic. Know the elements of your case. If they are subject to expert opinion, make sure that your expert is willing to state that it is more likely than not that the relevant fact is true. I have often had the precise experience of working with experts to change their use of “indicates” to “demonstrates” or similar such language. If you are in litigation or at risk of litigation, ignore this issue at your peril.

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