Abstract: At 9:45 a.m. on December 6, 2003, Employee #1 was working as a laborer for a construction contractor that specialized in hydrodemolition blasting operations. He was a union member hired from the union hall. Employee #1 was working at the bottom of an approximately 180 ft by 42 ft by 18 ft concrete pit called a clarifier, which is used to settle out sewage. Employee #1 was operating a 6 in. vacuum hose at the bottom of the north end of the clarifier, vacuuming excess water and debris. While walking backward, he tripped over the vacuum hose and sustained a fracture of the lower leg. He was hospitalized.