Abstract: At approximately 11:35 p.m. on March 14, 1990, Employees #1 and #2 were working in the C-cat unit at the Citgo Refinery in Lake Clade, LA. They were standing on an overhead pipe rack cracking a valve on a 10-in.-diameter steam line to allow steam to flow into downstream piping. The pressure in the line was approximately 250 OPR. There was a sudden unexpected rupture in two 10-in.-diameter steam lines approximately 10 ft upstream from where the employees were working. The sudden eruption of steam knocked Employee #1 from the pipe rack 15 ft to the ground. He suffered a head fracture and died on March 20, 1990. Employee #2 was knocked onto the pipe rack, and he sustained shrapnel wounds to his back. The employees were not wearing fall protection.