Aug. 14 (UPI) -- Denver fire officials believe natural gas is to blame for an explosion at a residential building that left nine people injured, one critically, Tuesday.
The blast happened near the intersection of 4th Avenue and Santa Fe Drive in the Baker neighborhood, the Denver Fire Department said.
Emergency officials transported two of the injured to Denver Health hospital, one critical and one stable.
Denver Fire Capt. Greg Pixley told reporters the blast also caused damage to a building across the street from the main structure, as well as vehicles.
"As you can see, the devastation behind us is pretty significant," he said.
He said at least one victim was trapped inside the building and had to be rescued.
The fire department said officials launched an investigation into the cause of the explosion.
"Until we can remove some of the debris, we'll have greater clues about the cause. Natural gas lines come from either the street or the alley," Pixley said.