At 0836 hours Station 9(California), Station 3(Lexington Park), Station 7(Hollywood), Tower 9, Truck 3, and Ambulance 389 were dispatched to 22599 Macarthur Bl in California for smoke coming from the building. Engine 72 responded immediately with 4 personnel and Rescue Squad 7 responded moments later with 4. Engine 31(running from Station 9) arrived on the scene at 0840 and advised they believe they have a working fire. Engine 72 arrived next picking up Engine 31's line. The Crew from Engine 72 advanced a hand line to the front of the buildings and started opening up the stores and searching for the fire. Engine 32 arrived and took the back side of the building along with Tower 13(NASFD). Engine 32 crew advised command that they had the fire in a back storage room and were putting a knock on the fire. Rescue Squad 7 arrived and assisted with laddering the building and search. Engine 72's crew teamed up with Tower 13 and assisted with opening up the roof and extinguishment of the fire on the roof. Units remained on the scene for several hours assisting with overhaul and smoke removal. Units from Station 7 cleared the scene at 1115 hours. The State Fire Marshal is investigating the fire. Chief 3B had Command.