SAN ANTONIO – Two house explosions just hours apart rocked a Northeast Side neighborhood along Preston Hollow Drive, sending five people to hospitals and prompting an investigation that now includes the National Transportation Safety Board.

RELATED: Three victims identified as gas leak source confirmed in North Side explosions

The first explosion happened just after 6 p.m., followed by a second blast just before 8:30 p.m. Roads in the area were blocked off for much of the day as investigators from the San Antonio Police Department, San Antonio Fire Department, and CPS Energy worked the scene. Some families were allowed back into their homes at times, while others were not, as crews searched for answers and tried to determine when it would be safe for residents to return.

Fire officials said early indications pointed to a natural gas buildup. Gas was also detected in nearby homes. CPS Energy said it has identified the source of the gas leak.

Neighbor Pete Gonzales said the first blast shook his home. “It was just like a sonic boom, the whole house vibrated,” Gonzales said.

Gonzales said he ran outside to help neighbors after the explosion and described the injuries he saw.

“They were out in the front yard, just crying for help, crying for 911 and you could physically see that they were burnt pretty pretty good. I’ve been thinking about them all night, praying for them,” he said.

In total, five people were taken to hospitals. Wayside Chapel youth pastor Tim Nowell, his wife, Kim — a teacher at MacArthur High School — and their teenage daughter, Ali, were injured in the first home explosion. Wayside Chapel and MacArthur High School were rallying around the family, saying they are in stable condition and face a long road ahead. Two people were injured in the second blast.

For neighbors, the explosions brought fear and uncertainty about when — or whether — they will feel safe returning home.

John Young, who lives in the neighborhood, said he has known the affected family for years.

“They’ve been there 18 years and we’ve been in the neighborhood for 33 years,” Young said.

He described the impact on residents: “So it’s a traumatic event.”

Young said he and his wife are staying in a nearby hotel until they get the all-clear to return, but he remains worried.

“In the back of my mind, I’m thinking I don’t want this to happen to my house,” he said.

Another neighbor described hearing both blasts, saying, “All we heard was this big crash from the first explosion. Then all of a sudden we hear the next one, and it way worse.”

After the first explosion, multiple first responders and CPS crews responded and the situation was believed to have died down. Residents were told they could return to their homes before the second explosion happened just before 8:30 p.m. Questions remain about who gave the all-clear after the first blast.

City Councilman Marc Whyte said crews located where the leak happened and that it has been identified and secured, but he has not said the source or location of the leak. CPS Energy also has not said where the leak was located.

Attorney Michael Lyons, who has handled other gas explosion cases and said he recently won a case against CPS in 2021, said gas explosions can happen for multiple reasons, including deteriorated pipes causing a leak. “A lot of these gas companies are turning a blind eye and playing whack a mole, simply solving the problem, after it’s too late to fix it,” Lyons said. He added that once gas reaches an explosive level, it can ignite.

“If it’s at an explosive level, somewhere between five and 15% natural gas to oxygen, if it meets a competent ignition source, it can blow up,” Lyons said.

Investigators from SAPD, SAFD and CPS Energy remained in the area as the investigation continued.