Abstract: Employees #1 and #2 were assigned to adjust the setting on a level data pressure sensor that was mounted on top of a soybean storage tank in order to regulate the low pressure nitrogen used to blanket the tank. The storage tank was 24 ft high by 30 ft diameter with a 262,000 gallon capacity. There was 1 in. of oil in the tank. Employee #2 had removed trash from the area and when he returned he could not locate Employee #1. After a short time Employee #2 climbed the tank ladder and, when he reached the top, he could see that the tank hatch was open. He looked in the tank and saw Employee #1 lying in the bottom. He yelled to Employee #3 for help, then entered the tank to assist Employee #1. Employee #3 climbed the tank and could see both Employees #1 and #2 lying in the bottom. He yelled for help, shut off the nitrogen flow to the tank, and climbed down. He was removing a side plate on the tank when coworkers arrived to assist. After removing the plate, Employee #3 held his breath and entered the tank and pulled Employee #2 to the opening. He was able to get out of the tank before being completely overcome. Employee #4 entered the tank and was able to pull Employee #1 out of the tank before being was completely overcome by the nitrogen atmosphere. Employee #1 died of asphyxia.