The role of epidemiology in the law: a toxic tort litigation case

Abstract

Toxic tort cases provide a natural framework for an in-depth illustration and an application of statistical methods for small-scale studies of putative sources of hazard. In this paper, we describe the aspects of a toxic tort case that focussed on quantifying the strength of evidence concerning the hypothesis that carcinogenic substances emitted from an industry source were associated with a statistically significant higher than expected incidence rate of neuroblastoma in children. We first present the epidemiological analysis carried out by the plaintiffs' experts (Drs P1, P2 and P3). We then summarize the key critiques by the defense experts (Drs D1, D2 and D3) followed by the plaintiff's reply. In the context of toxic torts, the plaintiff must demonstrate that the exposure resulting from the defendants' conduct is more likely than not causally related to the injury. We use this toxic tort case to identify common criticisms of the defense experts that take advantage of the complexity in evaluating causation in toxic torts. In the discussion, we summarize the common defense positions and question whether such questions are scientifically appropriate.