Also known as: superseding cause · supersedes causation · intervening cause
Written by attorneys · grounded in primary & secondary sources — see below
An intervening act or force of a third person that by its occurrence prevents an original actor from remaining liable for harm to another even though the actor's antecedent negligence was a substantial factor in bringing about that harm.
Sarah Sullivan negligently wounds Scott Summers during a confrontation. Summers is driven to a clinic for treatment. While waiting, a disgruntled patient opens fire and kills Summers. Sullivan's initial negligence satisfies cause in fact but the gunman's independent criminal act prevents her from remaining liable for the death.
Spencer Silver leaves a ladder unsecured on a roof. Sophia Singh climbs it to retrieve her cat after the ladder slips. The cat's fall injures Singh. Silver's negligence created the situation and Singh's rescue effort is a normal consequence so Silver remains liable.
Select any source to read its text and confirm it supports the definition.
Sabrina Shah leaves a car unlocked with keys inside. A thief steals the car and later crashes it into Stonehaven Properties' building. The theft and crash appear extraordinary rather than normal so the thief's conduct is a superseding cause relieving Shah of liability for the property damage.
Sasha Stone stores flammable materials near a busy walkway. A passerby accidentally knocks over a container and the resulting fire damages Synergy Systems' equipment. Stone's conduct increased the foreseeable risk of fire through third-party intervention so the passerby's act is not superseding.
Starlight Media negligently stages a loud explosion near a crowd. Sarah Sullivan panics and runs into traffic where she is struck by a vehicle. Sullivan's flight is a normal response to the fear created by the explosion so the media company remains liable for her injuries.
Southland Foods negligently leaves a loading dock gate open allowing stray dogs inside. Scott Summers attempts to herd the dogs out to protect customers and is bitten. Summers's efforts to avert the threatened harm are not superseding so the company remains liable.
An intervening force qualifies as superseding when it is an act of a third person or other force that by its intervention prevents the original actor from remaining liable for harm even though the antecedent negligence was a substantial factor in bringing about the harm.
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No. The intervention of a force that is a normal consequence of a situation created by the actor's negligent conduct is not a superseding cause of the resulting harm.
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Courts consider factors such as whether the intervention brings about harm different in kind from that which would otherwise have resulted, whether its operation appears extraordinary rather than normal, and the degree of culpability of any third-person wrongful act that sets the intervening force in motion.
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An act done by another in normal response to fear or emotional disturbance to which the actor's negligent conduct is a substantial factor in subjecting the other is not a superseding cause of harm done by the other's act.
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No. If the actor's negligent conduct threatens harm to another's person, land, or chattels, the normal efforts of the other or a third person to avert the threatened harm are not a superseding cause of harm resulting from such efforts.
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…that death. “The proximate cause of death is that cause which, in natural and continuous sequence, unbroken by any efficient intervening cause, produces the death, and without which the result would not have occurred. It is the efficient cause—the one that necessarily sets in operation the factors that accomplish the death.”…