Three utility workers were injured when a gas main fire broke out Wednesday at a busy intersection in Bedford, police said. The workers were taken to area hospitals with injuries not believed to be life-threatening, police said. National Grid spokesman Keith Giannini said workers from the company and a crew from Neuco Inc. were working on a gas connection project at Middlesex Turnpike and Crosby Drive when the gas main ignited. The fire spread to overhead lines, knocking out power to the area, police said. The cause is still under investigation, police said.Nicholas Jacques can be reached at firstname.lastname@example.org.