Also known as: intervening cause · intervening causation · superseding cause
Written by attorneys · grounded in primary & secondary sources — see below
A force or act that actively operates in producing harm to another after the actor's negligent act or omission has been committed. Such a force relieves the original actor of liability only when it qualifies as a superseding cause under the factors set forth in the Restatement rules.
Ian Iverson negligently left a construction trench unguarded. A third party deliberately pushed Ingrid Innes into the trench hours later. The deliberate push prevented Ian from remaining liable for the resulting injuries.
Iris Irons left a ladder leaning against a building. Imani Idowu climbed it in a normal effort to retrieve her dropped keys. The climb did not relieve Iris of liability for the resulting fall.
Imperial Motors parked a truck with an unlocked door on a hill. A passerby released the brake in an extraordinary manner. The release qualified as a superseding cause relieving Imperial of liability for the ensuing crash.
Select any source to read its text and confirm it supports the definition.
Island Manufacturing stored flammable materials near a public walkway. A foreseeable spark from a third party's cigarette ignited them. The spark did not supersede Island's liability for the resulting fire damage.
Ironclad Industries left a gate open near a busy road. India Inoue fled through it in normal response to fear created by the open gate. The flight did not relieve Ironclad of liability for the injuries that followed.
Ingrid Innes left an unstable scaffold near a sidewalk. Ian Iverson attempted a normal rescue of a trapped worker. The rescue effort did not supersede Ingrid's liability for the resulting collapse injuries.
An intervening force relieves the actor only when it qualifies as a superseding cause under the Restatement factors. The force must operate after the negligence and produce harm different in kind or appear extraordinary in light of the circumstances.
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No. An act done in normal response to fear or emotional disturbance to which the negligence is a substantial factor is not a superseding cause.
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A force that is a normal consequence of the situation created by the negligence is not superseding. Normal rescue efforts to avert threatened harm also fail to relieve the original actor of liability.
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When the negligent conduct creates or increases the foreseeable risk of harm through the intervention of another force, that intervention is not a superseding cause.
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…knocks down with his car a pedestrian and a third person then ran over the prostrate person. That involves the question of intervening cause which we do not have here. Moreover it is out of harmony with the current rule on that subject and was properly questioned in Hill v. Peres , 136 Cal.App. 132 [28 P.2d 946] (hearing in…