Abstract: At approximately 11:45 a.m. on April 4, 1985, Employee #1 was cutting the sheetmetal top of a digester into 4-ft by 16-ft sections, with an 8-ft pie-slice-shaped bottom. The approximately 75-ft-diameter roof was 25 ft above a concrete floor and had three existing 4-ft by 8-ft openings. Employee #1 was assisting a coworker with a torch, cutting sections one at a time that were then lifted out by a crane. Employee #1 and the coworker had just prepared a section for removal and the crane operator saw Employee #1 walking parallel to the opening as the lift started. He then saw Employee #1 fall through the opening and stopped the lift. Employee #1 sustained head and internal injuries and was killed. The openings were not guarded, nor was personal fall protection equipment being used.