Document Type



Judges | Torts


Judge Richard A. Posner’s opinion for the Seventh Circuit in Indiana Harbor Belt Railroad Co. v. American Cyanamid Co., concerning a spill of the hazardous chemical acrylonitrile at a railyard near Chicago, is considered the definitive statement on the abnormally dangerous activity doctrine. That doctrine (also known as the ultrahazardous activity doctrine) holds that one who engages in an abnormally dangerous activity is strictly liable for harm caused to others, regardless of negligence. However, Judge Posner’s opinion suggests that strict liability should rarely displace the negligence standard, even for commercial activities that externalize high degrees of risk. That approach leads courts to avoid invoking the doctrine by failing to classify activities as abnormally dangerous.

Indiana Harbor has been enormously influential. It is included in most Torts casebooks, imbibed by future lawyers and judges, lauded by commentators, and frequently cited. The unfortunate result has been to unduly constrict use of the abnormally dangerous activity doctrine.

It is not hyperbole to say that Richard Posner is a genius; yet, as this Essay demonstrates, his reasoning in Indiana Harbor is deeply flawed. The chasm between the decision’s reputation and its real quality is so enormous that the opinion deserves to be named the worst torts decision in American history. By revealing Indiana Harbor’s flaws, this Essay opens a way to reconsider and revive a potentially valuable torts doctrine.