Abstract: Employees #1 and #2 were using a #50 Hyster forklift to clean a freezer that contained pallets of frozen crab. The freezer was 44 ft by 55 ft by 16 ft and had doors large enough for a forklift to enter. The employees had been working for several hours, and each time the forklift would enter and leave the freezer, the doors would shut. Employee #3 was looking for a freon leak in the freezer fans. He had been concerned with this problem for some time and had been working on the fans for seven hours that day. All three employees began to feel tired and then got "splitting headaches." Employee #1 recognized the symptoms of carbon monoxide poisoning and had all employees removed from the freezer and taken to the hospital. The carboxyhemoglobin levels of all three employees were 20 percent. Emissions testing of the Hyster lift showed carbon monoxide levels at 530 ppm. High carbon monoxide levels combined with an airtight freezer operating at -10 degrees Fahrenheit had caused carbon monoxide poisoning.