Lower Allen Township, PA - Around 1030 hours, Box 12-03 sent West Shore area fire companies to 18th Street and Carlisle Road for a house fire. Reports indicated a passerby reported smoke from the house. First arriving units encountered a working fire in a two-story, single family, dwelling in the 1600 block of Carlisle Road. The status of the occupants at this point were unknown. Companies made an aggressive attack on the fire but the 1st floor collapsed into the basement making entry difficult and dangerous. Heavy fire consumed the basement and was extending thoughout the structure. Command 12 requested a second alarm bringing in mutual aid from York and Dauphin Counties to the scene. Several hand lines, blitzfires, and a master stream from Harrisburg Tower 3 attacked the fire from the exterior for almost an hour before bringing the flames under control. The two occupants of the home are missing and presumed dead in the rubble after a total collapse of the 1st and 2nd floor interior floors. Excavation equipment is being used to sift through the rubble to locate the victims.