On August 2, 1996, at approximately 5 P.M., a fire was reported in an office building in the 600 Block of N. Davis Street and a box assignment was “struck out” by the Communications Division of the Baltimore City Fire Department. A box assignment consists of 4 engine companies, 2 truck companies, a battalion chief, an air-flex, and medic unit. Engine companies bring water and hose, truck companies are equipped with the ladders and tools. Truck Company 1 arrived on the scene first and reported smoke showing from all floors of a 5-story building in the rear location. I, along with other members of Truck Company 1, put ground ladders in place and entered the building to search for any trapped occupants, to ventilate the structure, and to provide access to the seat of the fire for incoming engine companies. Upon entering the building, we encountered extremely dense smoke and intense heat. I made my way to the 5th floor stairwell, after performing a primary search of the rest of the building, and was about to enter that floor when I heard an engine company advancing a hose-line from the floor below to my location. This is typical of aggressive interior firefighting operations that are necessary to limit the fire from extending to adjoining structures. I utilized a ceiling hook to penetrate the ceiling and exposed the seat of the fire in that space. Due to a delay in getting the charged hose-line in place, the fire progressed very rapidly, as it was being exposed to more air and the area “flashed over”. A flashover occurs when the internal temperatures are sufficient enough to ignite the flammable gases that occur, as a result of the thermal layering of those gases in enclosed spaces. The force of the simultaneous combusting of those gases was enough to send me over a railing and down the stairwell to the first floor. I hit the ground with enough force that it caused the separation of components of my helmet to occur. The incident escalated to 5 alarms, which should sufficiently show the severity of the fire and the severity of the mechanism of the injury suffered. Despite the severity of the injury, my post-surgical recovery went remarkably well and I was able to return to the full performance of my duties within 3 months.