An intervening cause is a defense to a negligence claim.  If an event occurs following a defendant's act that is unforeseeable and causes an injury, this may cut off the liability for the defendant's act.  

A negligence claim requires a defendant's action cause the injury and that the injury be reasonably foreseeable.  An intervening cause may break the connection between the injury and the defendant's action, and thus destroy a negligence claim.  If the intervening cause is foreseeable, however, the defendant will still be liable.  In some jurisdictions, an intervening cause that removes liability is called a superseding cause.

There are two types of intervening causes:

  • Dependant intervening causes are set in motion by the defendant and will usually not relieve the defendant of liability unless it is an extraordinary response.  This is by definition very rare. 
  • Independent intervening causes are events that arise totally independent of any action by the defendant.  If it is unforeseeable and causes the harm, it relieves the defendant of liability.

What Is Considered an Intervening Cause?

The most common forms of intervening causes cited by defendants are acts of nature and criminal conduct.  Natural forces include weather, earthquakes, and animals.  If the weather was reasonably foreseeable, however, this will not absolve the defendant of liability.  So if the weather report warned of bad weather or it was clear to the average person that the weather would be bad, this claim will not succeed.

Criminal conduct by a third party may remove liability, as long as the defendant did not negligently contribute to the criminal act.  For example, a defendant who borrows a car and then leaves the keys in the ignition and the car unlocked is liable if the car is stolen because he did not take basic, reasonable precautions.

Do I Need a Lawyer?

The laws regarding negligence are very complex and can differ immensely from state to state.  An experienced personal injury attorney can advise you of the law in your area as well as any defenses you may have to a negligence claim.  A lawyer can also represent you in court.