Six firefighters were hurt, with one suffering life-threatening injuries "after inhaling superheated gases," while fighting a blaze at a two-story residence at 627 Felton Street early this morning. According to Chron, "The names of the injured firefighters - one of whom is a battalion chief - were not released." No civilians were injured since the building was vacant and the blaze was under control by 1:45 a.m. No word yet as to what caused the blaze. (Also, fire battles aside, check out the Emergency_In_SF, whose Twitter feed reports on any emergencies ranging from cut gas lines, surf rescues, kayaks in distress, fires, police action, and more.)