Abstract: At 2:30 p.m. on September 11, 2017, Employee #1 and Coworker #1, employed by a construction company, were engaged in excavation and trenching work at a residential property. They were tasked with removing an existing drainage pipe and replacing it with a new pipe. Coworker #1 was operating excavation equipment, and Employee #1 was working in the excavation made to access and remove the existing pipe and install new pipe. The excavation was reported to be 11 to 21 feet long, its width varied from 2.5 feet to 10 feet, and its depth was 6.2 feet. A 2.5 feet by 10 feet trench, where the new pipe would be installed, extended from the excavation. As Employee #1 worked in the excavation, a loose stone dislodged from the east vertical face, struck him, and knocked him to his knees. The east face of the excavation collapsed, and Employee #1 was buried and trapped up to his waist. Emergency services were called and, after Employee #1 was trapped for 30 to 40 minutes in the cave-in, emergency responders extracted him from the wet soil. Employee #1 was transported to the hospital, admitted, and treated for a fractured pelvis. He required four surgeries, a blood transfusion, and physical therapy. During the subsequent investigation, it was determined that the excavation had been made in Class C soil that was wet and had a compression strength of 0.25 to 0.5 ton per square foot. The soil had not been classified, and cave-in protective systems had not been used during the excavation work.