At 0436 hours, Box 1-4 sent Squad 8, Wagon 4, Towers 1,2, and Chief 5 (Wise) to the area of Swatara and Hummel streets for a reported 2 structures on fire. PD advised 2 vacant structures, both to be working, in the area of 301 Nectarine Street. Chief 5 requested the first alarm enroute at 0439 hours. Wagon 3, Rescue 69, and Air 13 made up the assignment. Chief 5 arrived on the scene with a 2 story, ordinary, well involved including the utilities. Wagon 4 stretched a 2.5 " step gun to the rear, operated the deck gun, and supplied Tower 1 with a 3" line off of Hummel Street. Squad 8 supplied a 5" supply down Nectarine from Kittatinny Street. Wagon 3 and Tower 2 positioned themselves down Reese Street from Crescent Street and set up aerial operations. The fire building collapsed about 10 minutes into a pile of rubble with all members reported uninjured. Companies remained on the scene for extended overhaul, bringing an excavator to the scene to clear the rubble and extinguish hot spots.