The explosion occurred in the 9300 block of Ingalls Street, near the old Westminster Mall, around 11:30 a.m.
"We heard the loud boom and ran to the driveway and we saw the roof lift off the house and things just blowing everywhere," neighbor Liz Young said.
Emergency responders initially evacuated several blocks around the blast site, but they were allowing most people to go back into their homes Thursday night.
"Upon arrival crews found one home destroyed, another severely damaged and several surrounding homes with minor damage," said Diana Wilson with Westminster Fire.
"My daughter and I kept smelling gas. She said, 'Mama, I can smell gas.' I said, 'Yeah, I do too' and [the smell] kept coming and fading and everything. And all of a sudden there was a big old boom," Arlene Gallegos said.
The residents of the destroyed home have not been located, officials said, but three people earlier considered "unaccounted for" have now been contacted.
Four pets from the home that exploded have not yet been found.
The North Area Tech Rescue Crew has been called in to search the wreckage of the home.
Two other people had minor injuries, Wilson said. She said one police officer was injured by glass and one Xcel worker was checked out as a precaution.
See photos from the scene: http://ch7ne.ws/12qyPBS
The suspected cause of the explosion is a gas leak. Westminster Fire investigators said they are are working with Xcel Energy on the investigation.
Roger Schweger and his family were allowed to go back into their home across the street from the blast site Thursday night to survey the damage.
Their windows were broken and the frames bent from the impact of the explosion, and inside the home, pictures were knocked off the walls and family heirlooms were broken on the floor.
"It’s a mess. It’s a little overwhelming," said Schweger. "Obviously, it could be worse. It will all clean up. It will all fix – nobody got hurt."