BVFD was Dispatched to a Large Shed on Fire Fully Engulfed. Firemen Arrived on Scene and Found a Large Shed Burnt Completely to the Ground. Firemen Initially Pulled a Cross Lay off and Began Extinguishing the Fire while other Firemen Set Up Drop Tank Operations. The Majority of the time on Scene Firemen were doing Overhaul. The Fire was Determined to be Started by a Controlled Burn that was Left Unattended. Due to the Ground being so Dry, and the Temps being 100+, the Fire Quickly Spread Through the Yard into the Shed. Firemen Were on Scene for Approx. 1 1/2 hrs.