SPRINGFIELD, Mass. (AP) -- Building inspectors say preliminary investigations show more than 40 buildings were damaged in a natural gas explosion in western Massachusetts that injured 18 people.
A strip club was flattened and a day care center was heavily damaged in the massive blast Friday night in Springfield.
Investigators are trying to figure out what caused the blast that could be heard for miles, left a large hole in the ground where the multistory brick building that housed the strip club once stood and scattered debris over several blocks.
Officials already had evacuated part of the entertainment district after responding to a gas leak and odor reported about an hour before the explosion.
Most of the injured were gas workers, firefighters and police officers.
Authorities have cordoned off the center of the explosion as building inspectors worked to identify unsafe structures. Preliminary reports show the blast damaged 42 buildings housing 115 residential units.
Three buildings were immediately condemned. Officials say 24 others require additional inspections by structural engineers to determine whether they're safe.