Abstract: At approximately 2:10 p.m. on July 17, 2003, Employee #1, a laborer, was working at the Roseville Water Treatment Plant (the Plant) on the Plant's expansion project. The Plant was adding a water treatment plant reservoir (6 Million Gallons). This expansion requires installation and expansion of the existing under-ground water lines. Employee #1 and a coworker, a backhoe operator, were excavating around a 66 in. diameter water pipe. They were attempting to locate the 66 in. pipe (pot- holeing) to determine its location for future connections and expansion of the water line. As the coworker was dumping a bucket of soil in the spoils pile, the employee entered the unprotected excavation and was standing in the deepest section of it. While standing in the 8 ft deep section of the excavation the north-east wall of the pot-holed excavation collapsed. The soil collapsed onto Employee #1 pushing him against the north west wall of the excavation. The coworker jumped into the excavation in an attempt to rescue Employee #1 but was unsuccessful so the coworker left to get help from others. A rescue attempt was made but Employee #1 died at the scene. Employee #1 died from a massive head trauma that was caused when a large chunk of the collapsed excavation hit him in the head. The employee was not wearing a hard hat. The sides of the excavations had vertical walls and the supervisor failed to direct the coworker to slope back the excavation in a 1 to 1 slope or to provide shoring for the employee who may need to go into the excavation.