Abstract: At approximately 12:40 a.m. on January 14, 1996, Employee #1 entered RT-53, a reduction and distillation vessel, to remove the TCC shaft that had become disconnected and had fallen into the vessel. RT 53 contained an argon atmosphere and Employee #1 collapsed after descending into the vessel by riding a hoist to the bottom. At approximately 12:45 a.m., Employee #2 entered the vessel by sliding down the hoist cables. He also collapsed before reaching the bottom of the vessel and fell 4 to 6 ft due to hypoxia. Employee #1 died at the scene. Employee #2 regained consciousness. Suffering minor contusions, Employee #2 was hospitalized overnight and released.