An expert witness testifying on causation should directly deal with the issue of alternative causes.

The US Court of Appeals (7th Circuit) in Schultz v. Akzo Nobel Paints, LLC, 721 F. 3d 426 dealt with a painter who developed acute myeloid leukemia (AML) and later died.

The lower court granted a motion for summary judgment for the defense striking the testimony of the oncologist, Gore, under Daubert.

The court reversed the ruling and found that Gore properly dealt with the alternative causes of AML in this case.

The court stated:

The district court also suggested that Dr. Gore’s opinion was unreliable because he failed to rule out other potential causes of Schultz’s AML, including Schultz’s weight and smoking history.

Unlike the expert in Myers, Dr. Gore considered which alternative causes should be ruled in, and which could be ruled out. He “determined that [Schultz’s] smoking history may have contributed, but [he] found no evidence that any other risk factor played a role.” He further “ruled out, to a reasonable degree of medical certainty, that any other known risk factors for AML contributed to Mr. Schultz’s disease.” In fact, Dr. Gore’s report thoroughly addressed the possibility of alternative causes, explaining that:

[N]o case of cancer truly has only a single cause. Because cancer development is a complex, multistage process where many factors work together to contribute to the ultimate emergence of a full blown malignancy, each of those factors … must properly be considered a cause of the ultimate cancer and a substantial factor in bringing it about…. Thus, critically for the purposes of a specific causation analysis, the mere fact that genetics and/or other environmental risk factors … have been identified as probable causes of a particular case of cancer in no way refutes the possibility that chemical exposures being investigated have also played a substantial contributing role at one or more stages of the development of that person’s cancer.

In his deposition, Dr. Gore elaborated on the reasons why he concluded that exposure to benzene was a significant cause for Schultz, despite the history of cigarette smoking: “[T]obacco is one of the strongest causative factors … [but] it’s not as strong on a risk basis, per se, as Benzene…. As a matter of fact, the Benzene in the smoke is one of the things that is thought, potentially, to contribute to the development of leukemia….”

Daubert counseled that courts should focus “solely on principles and methodology, not on the conclusions that they generate.” 509 U.S. at 595, 113 S.Ct. 2786. Because Dr. Gore’s testimony does not suffer from either of the deficiencies that the district court attributed to it, the court erred by excluding it. Moreover, with Dr. Gore’s contribution restored to the case, we conclude that Schultz has presented enough to defeat Akzo’s motion for summary judgment.