Multiple injuries in Austin, Texas, house explosion

Multiple people were injured on Sunday when a two-story house collapsed in Austin, Texas, and at least 23 other homes were damaged after witnesses reported hearing a huge explosion, authorities said.

The two-story house collapsed in northwest Austin around 11:23 a.m. local time, according to the Austin Fire Department.

"When Austin Fire Department crews arrived on scene they found a two-story home that looked like it had suffered an explosion, which was leveled to the ground," Division Chief Wayne Parrish of the Austin Fire Department said at a news conference Sunday afternoon. "A second house, a neighboring house, had also suffered severe collapse damage."

Parrish said firefighters also found a vehicle on fire outside the house that was completely flattened

"They extinguished the car fire and there was also some smaller spot fires occurring in the debris," Parish said.

Firefighters extricated one critically injured person and another seriously injured person from the home that was leveled by the explosion, said Capt. Shannon Koesterer, spokesperson for Austin-Travis County EMS. Koesterer said a second critically injured person was extricated from the home next door, which partially collapsed in the explosion.

Koesterer said another adult patient was treated at the scene for minor injures and that two firefighters, including one who was hospitalized, suffered minor injuries while working at the scene.

"As far as we know, we have accounted for everybody that was in all of the residences," Parrish said.

Parrish added a excavators were being brought to the scene "to help us do more large debris removal."

Emergency medial services officials said a total of six people, including the critically injured victims, were injured in the incident, but there were no fatalities.

"With this size of explosion, we have approximately, that we know of right now, 24 homes that have reported damage in the area," said Parrish, adding that many of the damaged home had broken windows and blown-out garage doors.

Parrish added that reports were coming in that the explosion was heard as far away as Georgetown, about 25 miles north of Austin.

The Travis County Fire Marshal's Office is investigating the cause of the explosion. Fire officials said the Texas Gas Service confirmed that there were no underground natural gas lines leading to the house, but that the residence did have a propane tank.

Witness Chase Miller shared with ABC News a video he recorded from a parking lot near the scene of the explosion that showed a large plume of smoke billowing from the collapsed house.

Miller told ABC News he was in the parking lot and heard a giant boom, then saw the smoke and started recording.

The explosion was so loud that police in some surrounding communities said they received reports from residents who heard the blast.

"The explosion rocked our house and I looked to make sure my dogs were OK and grabbed my phone and turned it on," Ingrid Vanderveldt of Austin, who also recorded video showing damaged homes near the flattened residence where the blast apparently occurred, told ABC News.

In the video, Vanderveldt and her husband, who live in the neighborhood rocked by the blast, proceeded to inspect the neighborhood with other residents, finding broken windows and damaged doors up and down their street.