Abstract: On the Tuesday before the accident, Employee #1, a backhoe operator and plumber, dug out an 8 ft deep T-shaped trench to reach and top the city sewer line underneath the street. Because of a 24-hour advance notice requirement, City of Phoenix personnel could not top the line until the next day. Rain started on Tuesday night and continued all day Wednesday, so that the top was not done and the trench remained open until Thursday. Employee #1 and a coworker attempted to pump water out of the trench on Wednesday without success, and on Thursday morning after the rain had stopped they used a front end loader to scoop out the water. The city employees entered the unshored trench and installed the T-top there and in another trench approximately 125 ft to the east. They left at approximately 9:00 a.m. Employee #1 then entered the trench and began to install 6 in. diameter by 6 ft long sections of clay sewer pipe. At approximately 11:25 a.m., Employee #1 was walking away from the last installed piece when the west wall of the trench caved-in. He was killed.