Gas Leak Exposure Claim Rejected by Louisiana Court Over Lack of Medical Evidence

Occasionally, a gas distributor will face a lawsuit alleging the plaintiffs were “poisoned” by leaking gas. These suits are rare, because natural gas and propane are not poisonous (though in high concentrations in enclosed spaces, they can displace oxygen, leading to potential suffocation). However, a gas leak exposure claim does happen, and a recent example is a Louisiana Court of Appeals decision reversing judgments in favor of a large group of plaintiffs who were exposed to leaking natural gas. The case is Adams v. Entergy New Orleans.

Gas Leak

The case arose from a seemingly unconnected series of events in the fall of 2014.

First, a crew for Entergy, the natural gas utility in New Orleans, was conducting a normal gas leak detection patrol in a residential neighborhood. Such patrols generally use highly sensitive gas detection equipment that can identify gas coming out of the ground at minute levels, down to the parts per million level. The crew’s equipment sensed gas, and a repair crew was dispatched to the area. This crew pinpointed a gas leak coming from a crack in a 2-inch polyethylene underground main. The leak was fixed the same day.

Second, two weeks later in a nearby area, a drunk driver collided with a transport truck loaded with gasoline. This triggered a fire that melted the transport’s aluminum trailer, causing gasoline to spill onto the street and into storm drains along the side of the road. Fumes and smoke from the fire moved into the neighborhood.

Complaints of Symptoms

Finally, one week after the gasoline incident, another natural gas leak was found in the same area. Again, it was a leak in an Entergy underground gas main. This leak was repaired by Entergy personnel on the same day it was reported.

Residents of the area began to complain of a variety of symptoms, including headaches, nausea, abdominal cramping, diarrhea, dizziness and aggravation of preexisting lung, asthma and sinus conditions. A group of 79 residents attributed these symptoms to their exposure to leaking natural gas. They sued Entergy, contending it was negligent in the maintenance and inspection of its gas lines.

Award of Damages

The parties waived their right to a jury trial, and the case was tried before a judge in the summer of 2024. (It is not clear from the court decision why there was a delay of almost 10 years between the incidents in question and the trial.) The plaintiffs testified as to the smell of natural gas in their neighborhood, especially during the second gas leak, which they believed was the cause of their symptoms. They presented certified medical records that confirmed the symptoms they reported. However, they did not present any expert testimony to connect their exposure to natural gas to these symptoms.

On the other hand, Entergy did present the expert testimony of a toxicologist to discuss the effects of natural gas and odorant exposure on humans, as well as from two company witnesses who discussed Entergy’s notice of and response to the two gas leaks in question. The court took the case under advisement, and in March 2025, it came down with a decision. It found that “the symptoms were caused or aggravated by the natural gas leak,” and it found in favor of the plaintiffs. It awarded damages to each of the 79 plaintiffs in varying amounts, from nothing to a maximum of $5,000.

Points on Appeal

Entergy appealed this decision. It raised two points. First, it said there was insufficient evidence to support the trial court’s conclusion that it had actual or constructive knowledge of the conditions that caused the leaks in its system and that it could have prevented these leaks through the exercise of reasonable care. Second, it contended the plaintiffs failed to meet their burden of showing that the gas leaks caused their injuries.

On the first point, the appellate court found there was no evidence that Entergy had any prior notice of the conditions that caused these leaks. In fact, Entergy acted immediately to locate and repair the leaks as soon as it learned of them. It therefore concluded the trial court erred in finding negligence on the part of Entergy.

Necessary Expert Testimony in a Gas Leak Exposure Claim

On the second point, the court also found for Entergy. It cited the basic rule that, to recover damages, a plaintiff must prove a causal relationship between the injury sustained and the accident that caused the injury. It added that “where a conclusion regarding medical causation in not one within common knowledge, expert medical testimony is necessary.”

The court reviewed the testimony of 79 plaintiffs regarding their personal experiences during the gas leaks, including the smell of natural gas throughout the neighborhood and the physical symptoms attributed to natural gas exposure. However, the court noted the plaintiffs had presented no expert medical testimony, and it concluded their evidence was insufficient to show their injuries were caused by exposure to the gas:

“Plaintiffs have not presented sufficient evidence to establish by a preponderance of the evidence that their alleged medical issues were more probably than not caused by their exposure to natural gas during the incident. None of plaintiffs’ certified medical records attributed their illnesses to natural gas exposure, and their treating physicians did not link their symptoms to natural gas exposure.”

Lessons for the Defense

In addition, the court said circumstantial evidence pointed to the gasoline tanker explosion as the cause of the plaintiffs’ medical issues. Certified medical records for 17 of the plaintiffs indicated they attributed their symptoms to the gasoline tanker explosion and not to the natural gas leak.

Finally, the court relied on the clear testimony of the toxicologist presented by Entergy: The plaintiffs’ symptoms were not caused by exposure to natural gas. And while exposure to high concentrations of mercaptan odorant could have adverse medical effects, the amounts of odorant in the leaking natural gas were miniscule and would not even remotely cause any kind of illness.

While the Adams decision involves natural gas, its importance for the propane industry lies in its emphasis on the need for clear medical causation evidence to support a claim for injuries caused by exposure to leaking gas. Defense of such claims against propane distributors should not ignore that point.