Abstract: On June 2, 1989, while working on the third shift, Employee #1 and a coworker were assigned the task of replacing a manway gasket on a reactor in the special products unit. They reported to the control room and received safety instructions. They started the job at about 2:40 a.m., and took a break between 3:15 a.m. and 3:30 a.m. The manway with the new gasket was being lowered into place when Employee #1 started waving his hands to stop work and ran down the stairway. He collapsed after entering the building, still wearing his SCBA. Several employees came to his aid, but could not revive him. He was transported by ambulance to the hospital, where he was pronounced dead at about 4:45 a.m.