In Pluck v. BP Oil Pipeline Co. (09-4572), the Sixth Circuit built on its decision in Tamraz v. Lincoln Elec. Co., 620 F.3d 665 (6th Cir. 2010) (discussed here), and reiterated that a high standard governs expert causation testimony in toxic tort litigation.  Pluck affirmed the district court’s exclusion of a plaintiff’s specific causation expert under Daubert.  It emphasizes that causation must be supported by quantifiable and reliable data, both when pointing to the cause of the illness and when ruling out other causes.

The Plaintiff argued that gasoline spills from an underground pipeline owned by BP from 1946-1962 resulted in benzene contamination that caused her Non-Hodgkins lymphoma in 2002.  The Plaintiff moved into the area in 1996 and drank from a well with small levels of benzene contamination for a few months before BP installed a new well that remained free of benzene until 2003.  When benzene was again detected, a carbon filtration system was installed to capture it.  The levels of the chemical were at all times well below the EPA’s maximum level of benzene for drinking water.

The Plaintiff’s expert claimed that Plaintiff had been “heavily” exposed to benzene, and that the exposure had caused the disease.  The Sixth Circuit affirmed the district court’s rejection of those claims under Daubert, expanding on its decision in Tamraz that the expert must both “reliably rule in benzene as the cause” and “rule out alternative causes of her illness.”

The Court first noted that the expert did not have any reliable data to support his conclusion of heavy benzene exposure, and that benzene exposure in the record had always been within the EPA limitations.  Without quantifiable exposure data, the expert’s causation claim was nothing more than “speculation and conjecture.”  Second, the Court found that the expert had not adequately accounted for benzene exposure from the Plaintiff’s extensive smoking habit.  The expert’s failure to quantify the Plaintiff’s exposure to benzene from smoking (and the effect it might have on her disease) rendered his opinion unreliable.

The Sixth Circuit also took a hard line with the expert’s attempt to change his methodology after the Daubert challenge through a supplemental declaration.  The Court held that the district court correctly excluded the declaration as “a transparent attempt to reopen the Daubert inquiry after the weaknesses in the expert’s prior testimony have been revealed.”

Robin Weaver of our Cleveland office handled the case for BP.