Summary
Section 520 identifies the factors for determining whether an activity is abnormally dangerous, subjecting the actor to strict liability for resulting harm. The six factors are: (a) existence of a high degree of risk of some harm, (b) likelihood that the resulting harm will be great, (c) inability to eliminate the risk by exercising reasonable care, (d) extent to which the activity is not a matter of common usage, (e) inappropriateness of the activity to the place where it is carried on, and (f) extent to which the value to the community is outweighed by the dangerous attributes.
No single factor is dispositive; courts weigh all six in combination. The central inquiry is whether the activity creates risks that cannot be eliminated through due care, making negligence liability inadequate to address the danger. Strict liability ensures that those who engage in abnormally dangerous activities bear the costs of resulting harm.
Classic examples of abnormally dangerous activities include storing explosives, fumigating with toxic chemicals, crop dusting, and maintaining large quantities of hazardous waste. Normal activities such as driving, even though dangerous, are not considered abnormally dangerous because they are matters of common usage.
Key Elements
- 1High degree of risk of harm to persons, land, or chattels
- 2Likelihood that resulting harm will be great
- 3Risk cannot be eliminated by reasonable care
- 4Activity is not a matter of common usage
- 5Activity is inappropriate for the location
- 6Value to community is outweighed by dangerous attributes
Practical Application
Section 520 is applied in environmental litigation, industrial accident cases, and disputes involving hazardous materials. Courts weigh the six factors in light of local conditions—blasting may be abnormally dangerous in a residential neighborhood but not in a remote mining area. The section is also relevant to emerging technologies, as courts apply the factors to determine whether activities like hydraulic fracturing or autonomous vehicle testing qualify.
Exam Relevance
Abnormally dangerous activity questions require systematic analysis of all six factors. Do not simply conclude that an activity is dangerous—apply each factor. A common exam trap: an activity that is very dangerous but also very common (like driving) is not abnormally dangerous under factor (d). Also note that strict liability under § 520 does not eliminate all defenses—assumption of risk may still apply.