The National Transportation Safety Board says a construction project a quarter century ago led to the February 2018 natural gas leak in Dallas that killed a 12-year old and forced the evacuation of thousands. The Board issued a probable cause finding that largely blames Atmos Energy for various failures leading up to the fatal blast. Dallas Fire Rescue also was scolded.
On consecutive days, two houses on Durango caught fire. Dallas Fire Rescue investigators appeared to conclude faulty appliances in the homes were to blame, much to the dismay of NTSB board members. Atmos did not conduct proper testing to see if the appliances or the gas lines were faulty, the final report says. The third day, Feb 22, 2018, a home at 3534 Espanola blew up in the morning as 12 year old Michelita Rogers got ready for school. The girl died in the blast and several others were injured.
Investigators ultimately traced the problem to a gas main that broke. Complicating the matter was the weather, with persistent rains keeping the upper crust of soil saturated. With nowhere to escape, the gas migrated underground until finding porous soil under the homes, and seeping into the structures. Complicating matters, the soil filtered out the sulfuric smell that alerts people of natural gas.
The root of the problem began nearly a quarter century earlier. NTSB investigators told the board that a sewer line project in the neighborhood near Crown Hill Park that happened in 1995 damaged a gas main. The line finally gave way leading to the disaster.
The entire neighborhood had to be evacuated after the line was shut down. The more investigators looked the more they found.
“As Atmos’s leak surveys expanded further an unusually high number of leaks were detected in northwest Dallas, including 741 grade one or two leaks within the area” said Sara Lyons, one of the NTSB investigators.
Ultimately, the investigators found more than 12 hundred leaks within a short distance from ground zero, said NTSB chairman Robert Sumwalt.
The probable cause was determined to be “…the ignition of an accumulation of natural gas that leaked from the gas main that was damaged during a sewer replacement project 23 years earlier and was undetected by Atmos Energy Corporation’s investigation of two related natural gas incidents on the two days prior to the explosion. Contributing to the explosion was Atmos Energy Corporation’s insufficient wet-weather leak investigation procedures. Contributing to the severity of the explosion was Atmos Energy Corporation’s inaction to isolate the affected main and evacuate the houses. Contributing to the degradation of the pipeline system was Atmos Energy Corporation’s inadequate integrity management program.”
The NTSB leveled some of the blame leading up to the explosion at Dallas Fire Rescue for not recognizing the probability that a gas main, rather than individual gas problems at houses on the same block, was the issue.
“There are two fires on two consecutive days,” said Sumwalt. “That should have allowed them to start connecting dots and say ‘something serious is going on here.’”
As result of the investigation, the NTSB issued 14 safety recommendations with three issued to the Pipeline and Hazardous Materials Safety Administration, one to the Railroad Commission of Texas, three to the Dallas Fire-Rescue Department, five to Atmos Energy Corporation and two to American Gas Association Gas Piping Technology Committee, the NTSB said in a news release.
Atmos has not responded for comment. Dallas Fire Rescue has declined to answer questions.