An explosion destroyed a building and shook several others Monday night in Dubuque. It happened in the 400 block of Loras Boulevard, shortly after 4:00 p.m. Chief Rick Steines with the Dubuque Fire Department says a gas leak caused the explosion. He says they were called a little after 4:00 p.m. for the leak, which he says was caused by a machine that struck a gas main while working in the area. According to Chief Steines, they evacuated the closest house while they waited for the gas company to arrive. Steines says the gas company was in the process of shutting down the gas when it ignited and caused the explosion. One house was destroyed and others had windows blown out. The chief says there was one injury: a firefighter went to the hospital for a cut. As of Tuesday morning, Loras Boulevard remains closed between Chestnut and Bluff Street.