Toxic tort case alleging benzene exposure; Exclusion of the plaintiffs' specific causation expert; Daubert v. Merrell Dow Pharms., Inc.; Meridia Prods. Liab. Litig. v. Abbott Labs.; Nelson v. Tennessee Gas Pipeline Co.; Fed.R.Evid. 702; Best v. Lowe's Home Ctrs., Inc.; "Differential diagnosis" as an appropriate method for determining causation for an individual instance of disease; Hardyman v. Norfolk & W. Ry. Co.; Tamraz v. Lincoln Elec. Co.; The maximum permissible contaminant level for benzene in drinking water (40 CFR § 141.61(a)(2)); Whether the district court should have admitted the expert's untimely filed supplemental declaration; GED Integrated Solutions, Inc. v. Durotech Int'l, Inc. (ND OH); Pride v. BIC Corp.; Non-Hodgkins lymphoma (NHL); Parts per billion (ppb)

The court held that plaintiffs' specific causation expert's (D) opinion that the plaintiff-wife's (S) "low-level exposure" to benzene caused her NHL was not grounded in "sufficient facts or data" and did not reflect the "reliable principles and methods" required by Rule 702. Thus, the court affirmed the district court's order granting the defendant-BP's motion in limine to exclude D's testimony in this toxic tort case alleging benzene exposure. The case arose from benzene contamination allegedly caused by gas pipeline releases. Between 1948 and 1962, an underground pipeline owned by BP experienced 5 spills, resulting in gasoline seeping into the surrounding soil and groundwater. Testing showed the presence of benzene in some residents' wells. BP undertook remediation efforts, including a monitoring strategy as to the home the plaintiffs later purchased in 5/96. Benzene was first detected in the well on the property in 10/96 in the amount of 3.6 ppb. BP installed a new well in 12/96. Between 1997 and 5/02, the new well tested negative for benzene 22 times. In 10/03, benzene measuring 1.8 ppb was detected in the new well. Plaintiffs moved from the home in 2005 on the recommendation of S's doctor. S was diagnosed with NHL in 2002 at the age of 48. The district court agreed with BP's argument that D did not apply differential diagnosis in either his expert opinion or his deposition, but only did so in an untimely supplemental declaration filed five months after the deadline for expert reports. The court also agreed. The court has recognized differential diagnosis as an "appropriate method for making a determination of causation for an individual instance of disease." The plaintiffs admitted that D did not explicitly identify differential diagnosis as his methodology until filing his supplemental declaration, but argued that he identified and ruled out alternative causes for S's NHL without necessarily using the term "differential diagnosis." However, "merely claiming that an expert used differential diagnosis is alone insufficient to satisfy the reliability inquiry under Daubert." The court held that D could not reliably "rule in" benzene as the cause of S's NHL. The EPA has set the maximum permissible contaminant level for benzene in drinking water at 5 ppb. D did not ascertain S's level of benzene exposure or determine whether she was exposed to quantities of benzene exceeding the EPA's safety regulations. D concluded that "chronic low-level exposure can and does cause NHL," S "probably had an injurious exposure to benzene and other organic solvents considerably above background," and there was "no safe level for benzene in terms of causing cancer." The court found this analysis unpersuasive, particularly since the benzene levels in plaintiffs' wells never exceeded the 5 ppb level. While they argued that evidence of benzene exposure existed due to its presence in their wells in 1996 and 2003, "it is well-settled that the mere existence of a toxin in the environment is insufficient to establish causation without proof that the level of exposure could cause the plaintiff's symptoms." The court also concluded that even if D had properly "ruled in" benzene exposure as the cause of S's NHL, he failed to "rule out" alternative causes, as required under the differential diagnosis methodology.