Also known as: ultra-hazardous · abnormally dangerous
Written by attorneys · grounded in primary & secondary sources — see below
Conduct that creates a high degree of risk of serious harm to persons or property. The risk cannot be eliminated by the exercise of reasonable care and the activity is not a matter of common usage in the community.
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Ursula Upton knew the bison enclosure carried a posted warning against contact yet leaned over the fence to photograph a calf. When the bison gored her, the court treated her knowing and unreasonable exposure as a complete defense to strict liability for the abnormally dangerous animal.
Unity Underhill operated a chemical plant that released corrosive vapor across the property line onto Upland Industries' fabrication yard. The vapor pitted equipment and killed plants. The court held the release actionable as an unintentional invasion caused by an abnormally dangerous activity.
Ulric Unger conducted pressure tests on tanks without performing required valve inspections. A failed valve released vapor that crossed onto Ultra Precision's adjacent land and damaged stored parts. The court imposed liability because the abnormally dangerous testing caused the harmful entry.
Una Unger stored propane at a depot in an area where the activity was not abnormally dangerous. A sudden leak caused vapor to drift onto neighboring land and injure a worker. Because the storage was unintentional and non-negligent, the court found no liability for the entry.
Universal Motors performed open-air sandblasting that produced fine metallic dust traveling across a narrow inlet onto a homeowner's property. The court weighed the high risk of harm, the likelihood of great damage, and the inappropriateness of the location to classify the activity as abnormally dangerous.
Uliana Ustinova kept a border collie with known dangerous propensities on her farm. The dog bit a person who entered the land without permission. The court applied the same negligence rules that govern artificial conditions rather than strict liability because the possessor had not created an abnormally dangerous condition.
Contributory negligence bars recovery only when the plaintiff knowingly and unreasonably subjects himself to the risk of harm from a wild animal or abnormally dangerous domestic animal. In all other abnormally dangerous activity cases the defense does not apply.
Yes. An unintentional invasion that is actionable under the rules for abnormally dangerous activities satisfies the second branch of private nuisance liability even without proof of intent or unreasonableness.
…or (b) unintentional and otherwise actionable under the rules controlling liability for negligent or reckless conduct, or for abnormally dangerous conditions or activities. The defendant argues that the plaintiff has no protected interest in unobstructed access to sunlight. The defendant relies on the common law doctrine of ancient…
…noted in Cronin, the Restatement’s language is potentially misleading because “[i]t may suggest an idea like ultrahazardous
…for example, upon keepers of wild animals, or those who handled explosives or other dangerous
…case; and that a person is subject to liability for an unintentional invasion when his conduct is negligent, reckless or ultrahazardous
The actor is subject to liability if the entry causes harm to the land, the possessor, or a protected interest, even though the actor exercised utmost care to prevent the harm.
An unintentional non-negligent entry does not subject the actor to liability unless the actor was engaged in an abnormally dangerous activity at the time of the entry.
Courts consider the existence of a high degree of risk, the likelihood that resulting harm will be great, the inability to eliminate the risk by reasonable care, the extent to which the activity is a matter of common usage, its appropriateness to the location, and the extent to which its value to the community is outweighed by its dangerous attributes.
No. The possessor owes a trespasser only the same duty of care that applies to artificial conditions or activities on the land. Strict liability does not attach merely because the animal is abnormally dangerous.