Also known as: superseding cause · superseding causation · intervening cause · superseding cause doctrine
Written by attorneys · grounded in primary & secondary sources — see below
An intervening act of a third person or other force that by its intervention prevents the actor from being liable for harm to another which the actor's antecedent negligence is a substantial factor in bringing about.
Select any source to read its text and confirm it supports the definition.
Summit Gas delayed repairs on a known gas leak beneath a residential block. Chase then illegally connected a portable grill to a utility line without permission. The connection triggered an explosion intensified by the unrepaired leak, injuring Marion. Because Chase's independent criminal act directly produced the blast, it prevents Summit Gas from remaining liable despite its antecedent negligence.
Sky Hotels failed to repair a broken exterior light despite repeated complaints. Nina, a stranger, selected the dim lot for a carjacking after passing better-lit areas. Dawn was carjacked as a result. Nina's selection of the darkened spot was a normal consequence of the situation created by the hotel's negligence, so it does not relieve the hotel of liability.
Birch Media sold unsecured glass bottles in an upper balcony despite warnings about intoxicated patrons leaning over railings. An unprecedented downburst storm then struck the venue. Henry, already intoxicated, dropped a bottle from the balcony onto Norman below. The storm's operation produced balcony-to-ground injury different in kind from the trampling harm threatened by inadequate barriers, qualifying it as superseding.
The City of Alexandria installed an unanchored sculpture in a high-traffic atrium knowing school groups visited weekly. Isabel allowed her students to crowd against and push the sculpture. The sculpture toppled onto Hal. Because the museum's placement created or increased the foreseeable risk of harm through intervention of another force, Isabel's conduct does not relieve the city of liability.
A tavern owner served X excessive alcohol. X drove away and negligently crashed into P. X's accident occurred as a normal response to the emotional disturbance created by the tavern's negligence. The accident therefore does not constitute a superseding cause relieving the tavern of liability for P's injuries.
Summit Gas left a known gas leak unrepaired beneath a crowded festival area. Chase's illegal grill connection created an immediate explosion risk. A bystander attempted to move nearby propane tanks to avert the blast and was injured when one tank ruptured. The bystander's normal efforts to avert the threatened harm do not relieve Summit Gas of liability.
An intervening criminal act qualifies as superseding only when it is independent of and unforeseeable from the defendant's negligence and breaks the chain of legal causation. Courts examine whether the defendant should have realized the likelihood that a third person might commit the act. When the negligence created or increased the precise risk of the criminal intervention, the act remains within the scope of the original hazard and does not supersede liability.
Supporting sources
…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…
…the buyer's knowledge of a defect breaks the chain of proximate causation
…of its approach limit a manufacturer’s liability if the subsequent alteration or modification was the sole proximate cause
…first place, we are committed to the rule in negligence cases that where in the natural and continual sequence, unbroken by any intervening cause
…while the pipe was suspended. According to the OAJC, the operator’s alleged negligence was legally significant as a potential superseding cause
Courts ask whether the force operated in an extraordinary manner and produced harm different in kind from that threatened by the defendant's negligence. An unprecedented storm satisfies the extraordinary-operation test when it was unforeseeable and caused injury outside the original risk. The different-harm inquiry focuses on whether the resulting injury matches the type the negligence made likely.
Supporting sources
A third party's negligent supervision does not break the chain when the original actor should have realized that such negligence might occur. When the defendant placed an unstable object in an area frequented by school groups and provided only minimal barriers, the failure of a teacher to prevent students from pushing the object is a normal consequence rather than a highly extraordinary departure. Extreme departures from ordinary care, however, may qualify as superseding.
Supporting sources
Foreseeability determines whether the intervention was a normal consequence of the situation created by the negligence. When the defendant had actual notice that the condition increased the risk of the precise type of third-party conduct that occurred, the intervention does not supersede. Absence of prior incidents or deliberate bypassing of safer alternatives can support a finding that the act was independent and unforeseeable.
Supporting sources