As investigators seek cause of deadly Dallas apartment explosion, data shows natural gas leaks remain problem

A large explosion and fire at a Dallas apartment building Thursday killed three people, and injured and displaced several others. But even as recovery efforts have ended, an investigation led by the National Transportation Safety Board is still underway to answer questions about what went wrong.

The CBS News Texas I-Team has learned before the explosion, the apartment building located in the 400 block of East 9th Street was for sale and in escrow. The potential buyer planned to convert it into new low-income housing and had hired engineering firm, ECS Southwest, LLP to test the property's soil. A manager for ECS told the I-Team they had hired a drilling company to bore through the concrete and pull samples. 

Thursday afternoon, Atmos said a construction crew hit a gas line, which led to the subsequent explosion. 

The big question investigators are now looking into: was 811 called before digging? And if so, were the gas lines accurately marked? Texas state law requires companies call the Texas811 nonprofit before digging on any project to prevent damage to gas and water pipes. 

Data shows gas leaks remain problem in North Texas

While Thursday's incident may feel rare, last year alone Dallas recorded 924 major gas leaks classified as Grade 1, the most severe level. Nearly half were caused by third-party contractors digging into the ground. 

"Far and away, third-party strikes are the biggest hazard," said Abe Scarr, energy and utilities program director for the Public Interest Research Group. "The question is, why aren't utilities doing more to limit them?"

Scarr said that while these accidents are unintentional, they are not unavoidable.  

An April I-Team investigation found that since 2019, the rate of hazardous leaks per mile of main pipeline in Atmos' Mid‑Tex division has increased. At the time, Atmos said the rise reflects better leak detection and faster repairs, not worsening conditions.