Torts - Cases, Principles, and Institutions Fifth Edition, 2016a

Witt & Tani, TCPI 6. Causation
2. Toxic torts. Difficulties in proving causation bedevil toxic tort cases. Epidemiological
data are usually admissible to prove causation, but often that data does not rise to the level of a
preponderance of the evidence. See Shelly Brinker, Opening the Door to the Indeterminate
Plaintiff: An Analysis of the Causation Barriers Facing Environmental Toxic Tort Plaintiffs, 46
UCLA L. REV. 1289 (1999).
While state courts are open to the use of epidemiological data, they impose a variety of
standards to ensure its reliability and applicability. Some states require proof of both general
causation (that a type of toxin is capable of increasing the risk of a certain type of harm) and
specific causation (that the toxin caused the harm to this plaintiff). See, e.g., King v. Burlington
N. Santa Fe Ry. Co., 277 Neb. 203 (2009); Terry v. Caputo, 115 Ohio St. 3d 351 (2007);
Blanchard v. Goodyear Tire & Rubber Co., 2011 Vt. 85 (2011). In Iowa, this approach has led to
different specialists providing evidence for general causation (generally epidemiologists) and
specific causation (typically physicians). Ranes v. Adam Labs, Inc., 778 N.W.2d 677, 690 (Iowa
2010). Texas requires that the epidemiological studies offered to show general causation must be
studies of patients substantially similar to the plaintiff, which can be a high bar for plaintiffs.
Daniels v. Lyondell-Citgo Ref. Co., 99 S.W.3d 722 (Tex. App. Houston 1st Dist. 2003).
3. Martin v. Herzog redux. The decision in Martin v. Herzog, which we encountered above
in our section on statutes and negligence per se, offers one possible solution to the problem.
Judge Cardozo concluded his opinion in Martin with a reminder about causation and a holding
about the significance of breach for proof of loss causation:
We must be on our guard, however, against confusing the question of negligence
with that of the causal connection between the negligence and the injury. A
defendant who travels without lights is not to pay damages for his fault unless the
absence of lights is the cause of the disaster . . . . We think, however, that evidence
of a collision occurring more than an hour after sundown between a car and an
unseen buggy, proceeding without lights, is evidence from which a causal
connection may be inferred between the collision and the lack of signals. If nothing
else is shown to break the connection, we have a case, prima facie sufficient, of
negligence contributing to the result. There may indeed be times when the lights
on a highway are so many and so bright that lights on a wagon are superfluous. If
that is so, it is for the offender to go forward with the evidence, and prove the
illumination as a kind of substituted performance. The plaintiff asserts that she did
so here. She says that the scene of the accident was illumined by moonlight, by an
electric lamp, and by the lights of the approaching car. Her position is that if the
defendant did not see the buggy thus illumined, a jury might reasonably infer that
he would not have seen it anyhow. We may doubt whether there is any evidence of
illumination sufficient to sustain the jury in drawing such an inference, but the
decision of the case does not make it necessary to resolve the doubt, and so we leave
it open. It is certain that they were not required to find that lights on the wagon
were superfluous. They might reasonably have found the contrary. They ought,
therefore, to have been informed what effect they were free to give, in that event, to
the violation of the statute.
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