Abstract: At 11:30 p.m. on May 15, 1996, Employee #1, a firefighter, and coworkers responded to a structural fire that reportedly had resulted from an explosion. At the scene, it was apparent that there had been an explosion, and this made Employee #1 nervous. He and coworkers extinguished the fire burning at the front door of the building, and then entered. Employee #1 went to the second floor, where he encountered high heat and dense black smoke. He was wearing his helmet, turnout coat, boots, and Scott Air-Pak. Visibility was zero on the second floor and his flashlight did not penetrate the smoke. He later stated that when his low-air alarm sounded, he handed his hose to another firefighter and began to leave. He remembered getting to the top of the stairs and then waking up at the bottom of the stairs, but had no recollection of how he got to the bottom. Because of his injuries, he surmised that he fell. Once at the bottom of the stairs he could see the exit, so he removed his respirator, which was out of air, and crawled out of the building.