Chattanooga firefighters responded to a vacant house fire around 6:30 Saturday night on Dorsey Street.
Fire investigators tell Channel 3 there was heavy smoke and fire visible when the first firefighters arrived on the scene.
Firefighters initially forced their way in through the front door to try an interior attack, but the heat was extreme and the conditions were too dangerous, so everyone was ordered out and transitioned to a defensive operation.
Investigators tell Channel 3, it took firefighters roughly 20 minutes to get the fire under control.
The fire caused extensive damage to the house, with the dollar loss estimated at $40,000.