17-year-old male laborer (the victim) died and a coworker was injured after one of the unprotected walls (i.e., no shoring, shielding or adequate sloping) of the trench they were working in collapsed, striking and partially burying them with soil. The day before the incident the excavator operator had removed the trench shield used during the sewer installation project to facilitate the removal of broken sewer pipes. When work was resumed the next day, the trench shield was not replaced, and the victim and a coworker (pipe setter) went into the unprotected trench to replace two sections of pipe and to check the grade of the sewer line with a grade pole. While they were placing the grade pole inside the terminal end of the sewer line, a section of the trench wall caved in, striking and burying the victim to his mid-chest and his coworker to his knees. The foreman, who had been working above the trench at ground level, called 911 at 9:39 a.m. and requested emergency medical services (EMS). EMS, law enforcement, and the fire department personnel arrived within 5 minutes of the 911 call. The Fire Marshall assumed responsibility for rescue operations and site safety and, in his role as Incident Commander (IC), assigned Operations Officer duties to one of the fire fighters. The Operations Officer, realizing that the trench walls remained unstable and hazardous, directed coworkers, who had jumped into the trench to render assistance, to leave the trench until fire fighters could obtain the necessary protective systems to ensure safe rescue operations. Coworkers refused to leave the trench and continued digging to free the trapped workers. The Operations Officer asked law enforcement personnel to remove the foreman from the incident site when he demanded that EMS and fire fighters go into the unprotected trench. The foreman was removed from the incident site. While fire fighters were waiting for the arrival of protective systems, they set ground pads (sheets of plywood) along the side opposite the collapse to provide paramedics with a more stable point from which to lower an oxygen tank and oxygen administration equipment. Coworkers placed an oxygen mask on the victim. By this time he had become ashen in color and was semi-conscious, with a weak pulse and labored respirations. Both the victim and his injured coworker were freed by their coworkers, placed on backboards, and carried to the shallow east end of the trench. With assistance from fire fighters working above at ground level, coworkers lifted the victim and his injured coworker to fire fighters. They in turn carried the injured workers to an area where paramedics were standing by. Both workers were treated by paramedics and transported by ambulance to a local hospital where the injured coworker was admitted in serious condition and subsequently released. The victim underwent emergency surgery, experienced a cardiac arrest, and died at 2:03 p.m., approximately 5 hours following the incident. NIOSH investigators concluded that, to help prevent similar occurrences, employers should: 1) ensure that workers are protected at all times from potential cave-ins by an adequate protective system; 2) know and comply with child labor laws which include prohibitions against work by youths less than 18 years of age in occupations which have been declared by the Secretary of Labor to be particularly hazardous (Hazardous Orders); 3) ensure that whenever Professional Employer Organizations (PEOs) serve as co-employers, they highlight the age of minors and note the need for compliance with child labor laws; 4) identify all workers on the worksite who are under 18 years old and make their presence known to all other employees on the worksite. Inform all employees of the work assignments that are appropriate for these youthful workers and the limits on what they can do; 5) ensure that a competent person conducts daily inspections of excavations, adjacent areas and protective systems and takes appropriate measures necessary to protect workers; 6) provide workers with training in the recognition and avoidance of unsafe conditions and the required safe work practices that apply to their work environments. Additionally, NIOSH recommends; 7) all persons on an incident site should follow the directions of qualified rescue personnel who have assumed responsibility for rescue operations and site safety.