Abstract: At approximately 7:45 a.m. on May 9, 1995, Employee #1 dropped a personal notebook into a weir wall trough located 7 ft below the top edge of an 18 ft deep clarifier tank. He then traveled 23 ft to an extendable ladder that was tie wired approximately 5 ft above the clarifier floor in order to facilitate adjustments to the clarifier rake arm clearance. When Employee #1 climbed onto the ladder to access the weir wall trough, the weight of the ladder and Employee #1 exceeded the tie wire's limits and it gave way. Employee #1 and the ladder dropped 5 ft, then the base of the ladder began to slide toward the center of the tank. The clarifier floor is sloped to its center 3 ft per 42 ft run. Employee #1 fell 3 to 8 ft from the ladder and landed on the tank's concrete floor on his left side. He was killed.