Investigators are at the scene of an explosion just east of Sault Ste. Marie.  The explosion took place at a sports complex in Echo Bay creating major damage.  No one was inside the building when the blast took place at 5:00 a.m. Friday.   Firefighters are on the scene as well as Union Gas officials.  OPP say the Fire Marshall’s Office is on the way to help determine what caused this morning’s explosion.