A fire destroyed an Army Corps of Engineers storage building at Hog Island and Fort Mifflin roads in Southwest Philadelphia yesterday. There were no injuries. During the fire, near historic Fort Mifflin, one of the building's walls collapsed. In photo above, firefighters help a colleague who fell or was knocked over, apparently when a hose under pressure was disconnected. An aerial ladder (right) and a marine unit in the Delaware River also battled the fire.