WCFD was dispatched for a reported building fire on Fern Hill Road. Assistant Chief 51 (McClure) arrived to find heavy smoke and fire showing from a large one story office section of a warehouse. Chief 52 (Cotter) arrived and established Fern Hill Command and requested Tower 54 (Goshen) along with the Working Fire Dispatch. E52-1 was the 1st in engine company and established a water supply and led off with a 2 1/2" hoseline, quickly knocking down the main body of fire. E53 arrived and established a secondary water supply to the B side of the building. Additional units were staged on Fern Hill Road. R53's crew was split and assigned to force entry and perform roof ventilation. Tower 54 arrived and was positioned on the B side of the building and assisted R53's crews. Additional units from Station 51, 52 and 53 assisted with final extinguishment and overhaul. Air 46 (Downingtown) also responded to resupply SCBA bottles. Rehab was provided by Station 55 (Good Fellowship) and Medic 91 (Chester County Hospital ALS). The fire is being investigated by the West Goshen Twp Fire Marshall and the Chester County Fire Marshall's Offices.