(Portland, OR)  --  An investigation is ongoing into an early-morning fire that caused significant damage to a Goodwill store in northeast Portland.  Firefighters responded to the Goodwill at Northeast 122nd Avenue and Northeast Glisan Street around 3:00 this morning to find heavy smoke filling the building.  Investigators say it appears the fire started on a loading dock pad in the back of the store.  No injuries were reported.