King v. Burlington Northern Santa Fe Railway Co.
762 N.W.2d 24 (Neb. 2009)

Facts:

  • King brought this toxic tort action under the Federal Employers’ Liability Act (FELA).
  • He alleged that he contracted multiple myeloma during his employment with BNSF because of exposure to diesel exhaust emissions.
    • Multiple myeloma is a cancer originating in the bone marrow plasma cells.
  • After Bradley died in 2002, his wife, Vicki King, revived the action in her name.
  • Each party presented dueling experts.

History:

  • The district court sustained BNSF’s motion to exclude King’s expert testimony, concluding that it failed to pass muster under Daubert/Schafersman framework.
    • It reasoned that his methodology was unreliable because the studies he relied on failed to conclusively state that exposure to diesel fuel exhaust causes multiple myeloma.
    • Note: Daubert is a Supreme Court case that charges courts with determining whether scientific evidence is sufficiently reliable to be presented to a jury. The Supreme Court identified four factors used to determine the reliability of scientific evidence:
      • 1) Whether the theory can and has been tested;
      • 2) Whether it has been subjected to peer review;
      • 3) The known or expected rate of error; and
      • 4) Whether the theory or methodology employed is generally accepted in the relevant scientific community.
  • The Nebraska Court of Appeals affirmed.

Issue:
Whether the trial court erred in determining that the expert’s opinion was unreliable.

Holding:
Yes. Case reversed and remanded.

Reasoning:

  • General v. Specific Causation:
    • In a toxic tort case, general causation addresses whether a substance is capable of causing a particular injury or condition in a population, while specific causation addresses whether a substance caused a particular individual’s injury.
      • To prevail, a plaintiff must show both general and specific causation.
      • Prof: This is basically just actual and proximate causation.
    • Courts disagree on the appropriate relative risk threshold that a study must satisfy to support a general causation theory. Here, the court held that:
      • “Despite this disagreement among the courts, we believe that requiring a study to show a relative risk of 2.0 or greater is too restrictive when the expert relies on the study to support an opinion on general causation” (some courts even hold that 2.0 is enough to show specific).
    • However, the court declined to set a minimum threshold:
      • “We agree that it would be far preferable for the district court to instruct the jury on statistical significance and then let the jury decide whether many studies over the 1.0 mark have any significance in combination.In short, the significance of epidemiological studies with weak positive associations is a question of weight, NOT admissibility.”
  • Epidemiological Evidence:
    • When a party uses epidemiological evidence in legal disputes, the study’s methodological soundness and its use in resolving causation require answering three questions:
      • First, does the study reveal an association between an agent and disease?
      • Second, did any errors in the study contribute to an inaccurate result?
      • Third, is the relationship between the agent and the disease causal?
    • Here, the court remanded with instruction to conduct this analysis, along with Daubert.

Rule: The significance of epidemiological studies (relative risk) with weak positive associations is a question of weight, NOT admissibility.