Waukegan Firefighters responded to a fire at 133 S. Genesee st. around 6 am to find fire on the roof. The 30.000 sq/ft building use to house the Salvation Army store, but has been vacant for several years. Fire quickly spread and crews where forced to repositioned for a defensive attack. Command called for a MABAS box for change of quarters companies only around 0630 hrs ,a nd upgraded to a full box about 15 minutes after. Trucks from North Chicago, and Great Lakes Naval Training Center responded and where set up in Sector A. Additional Waukegan companies arrived as well as a Squad From Gurnee. Fire was contained to the original building, however occupants in both sector C and D received some damage from heat and smoke. By 0800 most of the fire was extinguished and there was partial collapse to the building. The cause is under investigation.