The state fire marshal is crediting public safety officials for evacuating part of the entertainment district in western Massachusetts' largest city before a natural gas explosion leveled one building and damaged others.

Fire Marshal Stephen Coan says it's a miracle no one was killed in the blast Friday evening in Springfield.

Gas company workers had been sent to investigate a possible gas leak in the commercial and residential area, 90 miles west of Boston. The explosion occurred an hour later.

Investigators are trying to figure out the cause.

The blast injured 18 people, many of them first responders. None of the injuries is considered life-threatening.

The explosion left a large hole in the ground where the brick building housing Scores Gentleman's Club once stood and debris scattered over several blocks.