Abstract: Employee #1 had finished working on an 11,000 gallon diesel fuel storage tank. He was wearing a North full face negative-pressure respirator with organic cartridges. Upon leaving the tank, he stated that he was having difficulty breathing through the respirator. Employee #1 had been out of the tank about three or four minutes when he suffered an apparent heart attack and died. Employee #1 has a history of heart problems, including previous heart attacks and angioplasty. He had taken a nitroglycerin tablet earlier. His last physical exam had been administered in January of the same year (1996). Monitoring was conducted during entry. Oxygen levels were 21.5; combustibles levels were 0; toxic levels were 0; and lel levels were l-0.