Intervening Cause

An intervening cause is a separate action that breaks the direct connection between the actions of the defendant and a loss or injury to another person. Usually intervening causes are actions by a third party or natural occurrence that alter the circumstances of accident.  As a result, intervening cause may be used as a legal defense in a civil lawsuit.

Nature of Intervening Causes

In a personal injury lawsuit, the plaintiff must demonstrate through the facts of his or her case, that the defendant was negligent, and that the defendant’s negligent behavior was the cause of the harm that the plaintiff suffered. A defendant may generally be able to avoid liability by showing that there was an event that took place in the time between the defendant’s actions and the plaintiff’s injury that was sufficient to replace the defendant as the actual cause of the harm the plaintiff suffered. This event is the intervening cause.

The existence of an intervening event does not automatically mean it will get the defendant off the hook.  Foreseeability is often the key to the validity of an intervening cause. If the foreseeability of the harmful act itself, and of the injury that was caused, are established regardless of the intervening event, then the defendant is likely liable regardless.

Examples of Intervening Causes

Not all events can be used as an intervening cause to avoid liability. The event as well as the resulting injury must have been unforeseeable to a reasonable person. For example, imagine that Neighbor A’s house is being renovated, and that he asks Neighbor B if he might store his car in Neighbor B’s driveway during the renovation. Neighbor B agrees. One day, Neighbor B decides to park A’s car on the street in order to do a project in her driveway. She leaves the car parked on the street for several days, during which time a hurricane blows through the area, damaging the car.

Neighbor A sues Neighbor B for the damage to his car, claiming she was negligent and careless to park the car on the street rather than keeping it in the driveway. Neighbor B responds that the hurricane was an intervening cause between her negligence and the damage to the car and that, in actuality, the hurricane was the actual cause of the harm to the car. Neighbor B can further assert that it was unforeseeable that the car would be damaged by moving it from the driveway to the street. Such a defense could help Neighbor B avoid liability for the damage done to Neighbor A’s car.

Getting Help

If you are a defendant in a lawsuit, and you believe that an intervening cause is responsible for the plaintiff’s injuries, talk to a qualified personal injury attorney. An attorney experienced in negligence lawsuits could help you determine whether the facts of your case support using an intervening cause as a defense.

Case Studies: Intervening Cause

Case Study 1: Hurricane Damage 

John asks Sarah to store his car in her driveway during home renovations. Sarah agrees but later decides to park the car on the street to work on her own driveway. Unfortunately, a hurricane occurs during this time, causing extensive damage to John’s car.

John sues Sarah, alleging negligence for parking the car on the street instead of the driveway. Sarah claims that the hurricane was an intervening cause, breaking the direct connection between her actions and the car’s damage. The court examines the foreseeability of the hurricane and its impact on Sarah’s liability.

Case Study 2: Unforeseeable Medical Complications 

Mary (the patient) undergoes surgery performed by Dr. Johnson (the surgeon). Following the surgery, Mary experiences severe complications that require additional medical treatment. Mary files a medical malpractice lawsuit against Dr. Johnson, claiming that the complications were a result of the surgeon’s negligence.

Dr. Johnson asserts that the complications were an unforeseeable intervening cause that could not have been predicted or prevented. The court evaluates whether the complications were directly caused by Dr. Johnson’s actions or if they were unexpected events that intervened and caused harm.

Case Study 3: Third-Party Actions 

Susan (the customer) slips and falls in a grocery store due to a wet floor caused by a leaking pipe. Susan decides to file a premises liability lawsuit against the store, alleging negligence in maintaining a safe environment. The store argues that the actions of Mark (a third party) who accidentally damaged the pipe and caused the leak were an intervening cause that absolves them of liability. The court examines the foreseeability of Mark’s actions and determines whether the store’s negligence directly led to Susan’s injuries.​