Family of mother, infant killed in Oak Cliff apartment explosion sues Atmos for gross negligence

Atmos Energy is facing another lawsuit over the explosion in May that left three people dead inside an apartment building. 

The family of Marysol Perez and her infant son, Eric Jr., is filing a lawsuit alleging gross negligence by the utility company. 

Perez and her son were killed in the explosion at The Clyde apartments on May 28. 

Workers digging near the building struck a natural gas line, which later caused an explosion, killing three people. 

The attorney for the Perez family says Atmos had documented gas leaks in the area in the weeks before, which the lawsuit claims made the explosion much worse than it should have been. 

"So, what happened in this case, there was a lot of gas up under this building that had leaked," said Ted Lyon, the Perez family attorney. "So when he hit the line, the gas was escaping and then when it ignited, it didn't just ignite the gas it was escaping, which was blowing out the building. That ignited all the gas under the building and created this huge explosion."

Atmos has responded to the lawsuit by saying that pressure testing on the gas line before it ruptured showed that it was operating properly 

The lawsuit also claims that Atmos had recorded more than 1,000 missed digs last year, where gas lines were not properly marked.

Lyon has spent the last 30 years representing victims of gas explosions, but he says what happened on May 28 at the Oak Cliff apartment building is the worst he's seen by far. 

"They haven't even found the baby's body," said Lyon. 

Perez's 10-year-old daughter "...survived the explosion and was found crawling through debris before being rescued by a stranger," according to a new lawsuit filed against Atmos Energy. 

A National Transportation Safety Board report found that workers digging for soil samples in the area struck an Atmos gas line that had not been identified and marked. 

The family's attorney says Atmos hired the line location company responsible for mapping the area. 

In a statement to CBS News Texas, Atmos says, "The safety of our communities and employees is our first priority ... Our hearts go out to the people who were lost, their families, and everyone who has been impacted by this tragedy."

The lawsuit also claims that documented gas leaks in the area in the weeks before the explosion may have caused gas to accumulate beneath the apartment building. 

The lawsuit, one of four that have been filed since the deadly blast, does not specify damages.