HOUSTON -- A CenterPoint crew was looking for a gas line leak Thursday when a southeast Houston home exploded, burning a woman and her mother inside, KPRC Local 2 reported.

Investigators said a gas explosion may be to blame for the fire on Nightingale Drive near Seagull Street at about 11:30 a.m.

"I was about to go to the bank, and then I heard a loud explosion. I thought it was a truck or something, and then we heard screaming, so we ran to the house," neighbor Maira Castaneda said.

Inside the home, neighbors said Dell Miles was calling for help. Her middle-age daughter, Angela Landry, who is confined to a wheelchair, was inside with her.

Both were burned by the fireball that ripped through the house. Neighbors could not get to them through the rubble.

Firefighters had to break down a door to carry them out.

"Both women had burns to upper extremities and arms. They both appeared like they're going to be OK," HFD District Chief Tommy Dowdy said.

The victims were taken to Memorial Hermann Hospital in critical condition.

The family's dog suffered burns.

Arson investigators are not yet sure what set off the fire. The explosion apparently originated inside the women's home.

"The back wall is kicked out, certainly the appearance of a gas explosion, maybe a leak inside the house," Dowdy said.

Firefighters and CenterPoint workers are trying to sort it out.

Neighbors said they noticed a strong odor of natural gas Wednesday night and reported it.