Updated Saturday, November 24, 2012 at 05:01 PM
SPRINGFIELD, Mass. — Preliminary investigations show more than 40 buildings were damaged in the natural-gas explosion in Massachusetts that injured 18 people, building inspectors said Saturday.
A strip club was flattened and a day-care center was heavily damaged in the explosion Friday night in Springfield, one of New England's biggest cities.
No one was killed.
Investigators were trying Saturday to figure out what caused the blast that left a large crater where the multistory brick building housing Scores Gentleman's Club once stood and scattered debris over several blocks.
Officials had evacuated part of the neighborhood after responding to a gas leak and odor reported about an hour before the explosion.
Gas workers venting a gas leak got indications that the building was about to explode and they ducked for cover behind a utility truck — along with firefighters and police officers — just before the blast, said Mark McDonald, president of the New England Gas Workers Association.
Most of the injured were in that group, and the truck that saved their lives was essentially demolished, he said.
"It really is a miracle," State Fire Marshal Stephen Coan said.
Officials also marveled how the 5:30 p.m. blast occurred when a day-care center next door was closed. The center's building was heavily damaged.
Lt. Gov. Tim Murray and Springfield Mayor Domenic Sarno were attending a tree-lighting ceremony when the explosion occurred. Sarno said some people mistakenly thought the boom was part of the holiday event.
The explosion blew out windows in a three-block radius, leaving at least three buildings irreparably damaged and causing emergency workers to evacuate a six-story apartment building that was buckling, police said.
Pieces of broken glass littered streets and sidewalks. It was unclear how many residents had been evacuated. A shelter was set up at a school, but city officials said no one stayed there overnight.
Authorities cordoned off the center of the explosion Saturday as building inspectors worked to identify unsafe structures.
Preliminary reports show the blast damaged 42 buildings housing 115 residential units, said Thomas Walsh, the mayor's spokesman.
Coan, the fire marshal, said his office is investigating the cause of the blast and its possible origin. The state's Department of Public Utilities was also investigating.
Springfield, 90 miles west of Boston, has about 150,000 residents. It's known as the home of the Basketball Hall of Fame, which is not near the blast site.