Abstract: At approximately 12:45 p.m. on April 12, 1995, Employee #1, a 38-year-old laborer, was cleaning geothermal scale from the floor of a large crystallizer tank at the Leathers Geothermal Plant, Calipatria, CA. He was vacuuming scale at the rear base of three rows of vertical deflector railings. The 40 ft long and 14 ft in diameter tank had been cleaned two years before by the same cleaning service. It had been removed from service and was being replaced by a new tank. The deflector breaks up solids from geothermal steam as it enters the tank at a pressure of approximately 300 psi and at a volume of 3 million gallons an hour. The tank had been inspected and confined space procedures were followed. As scale was removed at the base, one of the rails fell, followed by others. Employee #1 deflected the falling rails as he backed away from the area; however, he tripped and one of the rails struck his leg when he fell. 911 was called and the plant rescue conducted removal and first aid. Paramedics arrived and transported Employee #1 to a local emergency room. He was hospitalized for treatment of a fractured left tibia. A general citation was issued for not properly securing the rails prior to permitting workers to enter the tank. Rail security procedures have since been implemented to prevent falling rails.