Crews of Atmos Energy fanned out across a northwest Dallas neighborhood, trying to pinpoint the cause of a house explosion that killed a 12-year-old and injured four others.

The explosion was so violent that it blew the siding off the house. Neighbors were evacuated from their houses.

Over the last two days in the same neighborhood, there were similar incidents at two other houses. All three houses share a common alley.

The three incidents are just the latest possibly involving an Atmos gas line.

An Atmos Energy spokeswoman said in a statement “it is too soon to tell what caused this incident.” The statement said they were working with the authorities to figure it out.

On Saturday the National Transportation Safety Board (NTSB) announced it was sending three investigators to investigate the explosion of the single-family residence. Their team is set to arrive Sunday morning.

Records obtained by WFAA show that there have been at least seven other leaks within a block since 2010.

Two of the leaks were the result of faulty pipe fittings that became the focus of a WFAA investigation that began in 2007.

Faulty fittings, known as compression couplings, were often to blame for a series of home explosions. Homes were often reduced to rubble and people were left dead or injured.

The couplings would separate in the shifting North Texas soils.

Regulators at the Texas Railroad Commission rewrote the rules and vowed to fix the problems.

One of two home previously damaged in a fire the same week an explosion killed an 11-year-old girl in the same northwest Dallas neighborhood.
One of two home previously damaged in a fire the same week an explosion killed an 11-year-old girl in the same northwest Dallas neighborhood.

In 2010, Atmos Energy pledged to replace all the couplings. But the explosions continued.

In 2015, officials said a compression coupling was to blame for a southeast Dallas house explosion that injured two people. In 2016, a Lakewood family narrowly escaped serious injury after a natural gas explosion in their kitchen. Atmos would not say if it involved faulty compression couplings.

Crumbling cast iron gas transmission lines began another focus of the investigation after the pipes were ignored or left to rot underground.

"I mean what does it take?” Lakewood resident Jeremy Anderson said in 2016. “Another badly burned seven year old, or another child killed? Another woman burned from head to toe? When is Atmos really going to step in and fix the problem?"