Abnormally Dangerous Activities

The doctrine of strict liability for abnormally dangerous activities holds that a person who engages in an activity that is inherently dangerous and not a matter of common usage in the community is liable for the resulting harm regardless of the level of care exercised. Unlike negligence, which requires proof of a failure to exercise reasonable care, strict liability imposes responsibility for harm caused even by careful conduct.

The doctrine traces its roots to the English case of Rylands v. Fletcher (1868), where the defendants built a reservoir that flooded the plaintiff's coal mines through abandoned shafts the defendants did not know about. The House of Lords held the defendants strictly liable for bringing a dangerous substance onto their land that escaped and caused damage.

The Restatement (Second) of Torts Section 520 identifies six factors for determining whether an activity is abnormally dangerous: (1) a high degree of risk of some harm; (2) likelihood that the harm will be great; (3) inability to eliminate the risk by exercise of reasonable care; (4) the extent to which the activity is not a matter of common usage; (5) inappropriateness of the activity to the place where it is conducted; and (6) the extent to which the activity's value to the community is outweighed by its dangerous attributes.

Common examples of abnormally dangerous activities include blasting with explosives, storing large quantities of toxic chemicals, fumigation with poisonous gases, and crop dusting with pesticides near populated areas. Driving a car is not an abnormally dangerous activity because it is a matter of common usage and the risk can be reduced through reasonable care.

Strict liability for abnormally dangerous activities is a public policy doctrine — it places the cost of inherently dangerous activities on the person who chooses to engage in them, rather than on innocent victims. The person who profits from the dangerous activity is in the best position to absorb or insure against the resulting losses.

On torts exams, strict liability for abnormally dangerous activities should be considered whenever the defendant engages in an activity with unusually high risks that cannot be mitigated by care. The Restatement factors provide the analytical framework.