Abstract: At approximately 2:00 p.m. on July 20, 1990, Employee #1, of Allied Technology Group, Inc., was removing asbestos-containing material from the exterior of a large tank. He and his crew were working from a catwalk within containment. A section of the catwalk grating had been removed so that a 55-gallon drum of the waste material could be lowered by a winch. Employee #1 stepped on the section of removed grating and it skidded out due to the wet nature of the work. Employee #1 slipped and fell approximately 20 ft through the opening, landed on another catwalk. He was admitted to San Francisco General Hospital for treatment of his injuries.