Insights & Events

Washington Legal Foundation published an article by Hollingsworth LLP attorneys Aleksandra Rybicki and Alexa Halkias analyzing the “one molecule” theory of causation in ethylene oxide litigation.

The “one molecule” theory, sometimes referred to as “any exposure” or “any exposure above background” theories, is an argument that plaintiffs’ counsel and expert witnesses have advanced in cases involving chemical exposures. First in the asbestos context and now in ethylene oxide litigation, plaintiffs’ experts have invoked the theory as a workaround for identifying a threshold dose at which exposure to the chemical could cause the harm alleged. The article examines how these theories fared in early ethylene oxide litigation, as well as several recent decisions in which courts are increasingly skeptical of the claim that “any exposure” is causal.

As the authors explain, a growing number of courts have embraced their gatekeeping role and rejected plaintiffs’ causation theories at the dispositive motion stage, signaling a demand for reliable, dose-specific causation analysis in ethylene oxide litigation. As gatekeepers of causation reliability, courts are likely to keep confronting this issue as the multiple pending ethylene oxide litigations proceed nationwide.