Defining ‘res ipsa loquitur’

March 1, 2008 By    

There is a legal concept known as “res ipsa loquitur” that allows a jury to infer that an accident was caused by the negligence of a party without actual proof of that negligence.

John V. McCoy
John V. McCoy

This inference can only occur when the evidence establishes that an injury occurred; the product that caused the injury was owned or controlled by the party against whom the inference is sought to be applied; the product that caused the accident would not ordinarily happen without negligence; there is no evidence that anyone had tampered with the product that has caused the injury; and the plaintiff has been injured by the product in question.

When this theory of liability has been alleged, it usually is asserted against a defendant when the product that causes the loss has been destroyed in the accident and was in the exclusive control of a defendant.

A typical example would be an airplane crash. The operation of the plane is usually in the exclusive control of the pilot and the airline. When a crash occurs, the jury can infer that something went wrong in the handling of the aircraft by the pilot or airline since, absent negligent acts, these crashes don’t usually occur.

A defendant can defend against such a claim by developing other theories that could explain how the accident occurred that don’t implicate the defendant against whom the claim is being alleged.

This legal theory also has been used on occasion by defendants against a plaintiff.

Res ipsa loquitur might apply to the plaintiff if:

  • The plaintiff who is injured in a gas explosion had exclusive control of the gas system, gas appliances and/or gas lines in a home;
  • A leak in that system would not ordinarily occur without negligence;
  • There is no evidence that anyone tampered with the gas system, gas appliances and/or gas lines in the home that are alleged to have caused injury.

The significance of this defense is that the inference would be that the plaintiff did something that caused the accident, even if no evidence exists to put before the court. The reason no evidence might exist is that it has been destroyed in the accident, the plaintiff has lost his memory of his actions related to the accident or he has passed away since the accident and his statement or deposition was not ever taken.

"Res ipsa loquitur" allows a jury to infer that an accident was caused by the negligence of a party without actual proof of that negligence. (ŠISTOCKPHOTO.COM)
“Res ipsa loquitur” allows a jury to infer that an accident was caused by the negligence of a party without actual proof of that negligence. (ŠISTOCKPHOTO.COM)

It is common to have a destroyed accident scene, a plaintiff that has no memory and, on occasion, a deceased plaintiff that has given no statements. Many cases we defend have no evidence of a leak in the gas system at any time except shortly before the accident.

Under this set of facts, the res ipsa loquitur defense should be considered to permit the jury to infer that the plaintiff may have done something to cause the leak that led to the accident.

The theory has been rarely used by defendants and is traditionally used by plaintiffs against defendants. However, a few courts have allowed the defense to raise this theory to explain the accident. It still permits the plaintiff to put on evidence of other explanations for the accident.

Counsel raising this defense will be creating new law in many jurisdictions. But the law is an ever-changing set of rules. Pushing the envelope to new theories or broader application of theories like I recommend here is a regular part of the legal system. This theory is a powerful but rarely used tool in defense of cases, but in the right case should be considered.


John V. McCoy is president of McCoy & Hofbauer, S.C. and specializes in the representation of propane companies. He can be reached at 800-599-8300 or
jmccoy@mh-law.us.

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