Dallas, TX – Dallas Fire-Rescue confirmed four firefighters and four civilians were injured in a natural gas explosion at an apartment complex Wednesday, Sept. 29.

Three of the firefighters have been listed as critical and the last one, who was in stable condition, has been released from the hospital.

All four injured civilians were released from the hospital by Wednesday night.

The blast happened at a 2-story complex in the 5700 block of Highland Hills Drive, between South Lancaster Road and Interstate-45. The location is just blocks from Dallas Fire Station 54 and near Paul Quinn College.

DFR spokesperson Jason Evans said when crews arrived to investigate a leak they noticed the smell of natural gas around a building near the front gate. It was as those firefighters tried to pinpoint the issue that the worst happened.

“At some point during the course of investigating the odor, an explosion occurred; causing a partial collapse of the two-story apartment building,” Evans said in a statement.

Video from Chopper 11 showed one portion of at least one building in the complex is completely collapsed.

Debris from the explosion was blown onto other apartment buildings and a carport in a parking lot.

Mountain Creek Apts LP, the owner of the Highland Hills Apartments in Dallas sent CBS 11 the following statement:

Emergency management officials and first responders are on‐site working alongside property management personnel to assess the situation and work with displaced residents on relocation options. We are in the process of gathering information and awaiting the Fire Department’s report on the cause.

DFR says they have no information yet on exactly what caused the explosion.

Dallas’ Office of Emergency Management is in the process of coordinating resources and assistance for approximately 300 residents of an estimated 200 households from these apartments and a Red Cross emergency relief site in the Tommie M. Allen Recreation Center.

All buildings in the complex will undergo a thorough investigation and inspection process to allow residents’ safe return, the city said in a news release Wednesday night.

Atmos Energy also released a statement Wednesday night:

This morning, Atmos Energy was called by Dallas Fire-Rescue to the scene of an apartment complex on Highland Hills Drive in Dallas. After verifying that gas was shut off to the meter that supplies the apartment complex, our highly trained technicians began performing safety checks of Atmos Energy’s system. Atmos Energy has verified that our system is operating as expected, and we have found no indication that our system was involved.