Legal Definitions - dependent intervening cause

A dependent intervening cause is an event or action that occurs *after* a defendant's initial wrongful act but *before* the final injury, and which contributes to that injury. Crucially, this intervening event is considered a natural, foreseeable, or expected consequence of the defendant's original action. Because it is dependent on or a predictable response to the defendant's initial behavior, it does not break the chain of causation, meaning the defendant remains legally responsible for the resulting harm.

Examples:

• Car Accident and Medical Negligence: David negligently runs a red light and crashes into Sarah's car, causing her a broken leg. Sarah is taken to the hospital, where a doctor, due to a minor oversight, sets her bone incorrectly, leading to a more severe and permanent disability than the initial break would have caused.

  David's negligent driving is the initial wrongful act. The doctor's incorrect setting of the bone is the intervening cause. This medical error is considered "dependent" because seeking medical treatment for an injury is a foreseeable and necessary step, and some degree of medical error, while unfortunate, is a known risk within the chain of events following an injury. Therefore, David remains liable for Sarah's worsened condition, as the medical negligence did not break the causal link to his initial act.

• Creating a Hazardous Environment: A construction company, negligent in securing its work site, leaves a deep, unmarked trench near a public sidewalk. A pedestrian, walking at night, stumbles near the trench, becomes disoriented, and in an attempt to regain balance and avoid falling into the trench, trips over a nearby pile of construction debris (also negligently left by the company) and breaks an arm.

  The construction company's negligence in leaving an unmarked trench and debris is the initial wrongful act. The pedestrian's disorientation and subsequent trip over the debris while trying to avoid the trench is the intervening event. This reaction is "dependent" because it is a foreseeable and natural response for someone to try and avoid a clear and present danger created by the company's negligence. The company remains liable for the broken arm because the pedestrian's attempt to avoid the trench was a direct and foreseeable consequence of the hazardous environment they created.

• Damaged Property and Subsequent Weather: A homeowner, negligent in maintaining their roof, allows a significant portion to become severely damaged and unstable. A few days later, a moderate but not unusual windstorm occurs, causing the already weakened roof to collapse entirely, damaging the interior of the house and destroying valuable furniture.

  The homeowner's negligence in maintaining the roof is the initial wrongful act. The moderate windstorm is the intervening cause. This windstorm is "dependent" in the sense that it is a foreseeable and natural weather event that the weakened roof could not withstand. The collapse and subsequent damage were a direct and predictable consequence of the homeowner's failure to maintain the roof, making them liable for the full extent of the damage, even though the windstorm was the immediate trigger.