Emergency crews found one man under what was left of the house at 12247 S. Ada. He is in critical condition at Christ Hospital. Two other people were also transported to hospitals after they were struck by flying debris. They are expected to be OK.
Neighbors said debris was scattered and windows were broken as far as two blocks away. One resident told ABC7, "It felt like a bomb went off."
"It shook my house. I thought a tree fell on my house. That's how loud the explosion was and how hard it was," said Al Ward, neighbor.
"The whole house went boom, everything started shaking. And everybody on the block just came outside and we saw the house and we was like, 'dang, the whole house fell down,'" said Jaquan Matthews, neighbor.
Firefighter have not determined an official cause, but said it appears to have been a natural gas explosion. There were no flames.
"It just seemed to explode and basically blow itself out. So just there's pressures involved there that flatten a building and actually it's never rich enough to actually create a fire," said Dist. Chief Tim Sampey, Chicago Fire Department.
Crews shut down gas and electric service in the area.