Abstract: At about 2:15 a.m. on March 9, 2002, a fire fighter working the Sierraville Fire Department responded a call for mutual aid on a fire at Sierra Pacific Industries saw mill. The volunteer fire department responded to a fire at the Sierra Pacific Industries saw mill, the mill had been shut down and was being demolished, soon after arriving they sent out a request for mutual aid from two other fire departments in near by cities. The fire fighter worked for one of these departments. When he arrived, he was directed to help an engine company at the back of the building. Shortly after getting to the back side, he and another fire fighter entered the building through a side door, the area was dark and the fire could be seen toward the front of the building. After entering the building, the fire fighter stepped through an opening in the floor, and fell 16 feet to the floor below. The opening was 9 feet inside the door and 12 feet across. The fire fighter had a light on his helmet and a flash light in his hand. He had spotted the floor coming in, and the far floor, but failed to notice the opening in the floor. The fire fighter was seriously injured. First aid was provided and then flown to Washoe Medical Center in Reno, NV. He was treated for a broken back and a lower leg injury.