Abstract: At approximately 6:20 p.m. on December 1, 1993, Employee #1, a tank cleaner, entered a chemical-carrying tank trailer carrying a high pressure wash wand. A few moments later the driver of the tractor, who was sitting in the cab, felt the tractor trailer move and climbed atop the trailer to investigate. Through this dome he saw Employee #1 down in the trailer. Employee #2, a safety monitor, was summoned to help in the rescue attempt. Employee #2 immediately entered the tank and, while attempting to rescue Employee #1, also went down. Both employees were rescued by the fire department and flown by Life Flight to the hospital, where they both died. Employee #1 was wearing a respirator with organic cartridges. Both employees had entered the tank without testing for atmospheric conditions.