At 01:13 Hrs. this date The 15 House was dispatched to ConAgra (Chef Boyardee's) at the boiler house for fire on the roof. Chief 1501 responded and was advised that there was some fire visible. The Chief arrived and ordered The Wagon to hit the hydrant and lay in while the Truck was setting up for roof operations. Crews made the roof and found the fire to be knocked down by the maintenance staff. The crew from Truck 15-1 overhauled the ductwork and removed the insulation and other material around it that was smoldering. Crews remained on the scene for about one hour.