At approximately 10:00 a.m. on November 4, 2003, Employee #1 was filling a nurse tank from the bulk anhydrous ammonia tank at the ammonia plant. After the nurse tank was full, Employee #1 disconnected the hoses from the nurse tank and was exposed to anhydrous ammonia. The exposure resulted in burn injuries to his face, neck, chest, and one eye, and injuries to his respiratory tract. Employee #1 drove to the fertilizer plant a few blocks away and was taken immediately to a local hospital and transferred to a regional burn center. Employee #1 died of complications due to chemical inhalation a few weeks later. There were no witnesses to the incident. A company official visited the site approximately 15 minutes after the incident and found goggles and gloves on the ground, the riser liquid and vapor valves closed, and the nurse tank vapor valve open. The company official also found the vapor hose end valve connected to the nurse tank and open, the nurse tank liquid fill valve closed and the liquid hose end valve open and lying on the ground. It appeared that Employee #1 was exposed to the ammonia remaining in the liquid hose between the riser valve and the hose end valve. The exposure appeared to have occurred either because Employee #1 did not close the hose end valve before disconnecting the hose from the nurse tank, or because the safety catch did not engage when the valve was closed, and the valve handle was bumped, causing the valve to open. There was evidence that Employee #1 applied snow to the injured areas. The required water supply had approximately one inch of ice on the surface.