Abstract: Employee #1 and two other laborers were excavating a trench in an attempt to locate a 4 in. natural gas main. Employee #1, the crew leader, was operating the backhoe. When the trench reached a depth of about 5 ft, Employee #1 entered the trench and used a shovel to tap what appeared through the mud at the bottom of the trench to be the gas main. Employee #1 exited from the trench and made another one to two scoops with the backhoe bucket. The trench was now approximately 7 ft deep by 24 in. wide by 12 to 15 ft long with vertical walls. When Employee #1 entered the trench again used his arm to feel for the gas main through the mud at the bottom of the trench, sections of both the north and south walls caved in and buried him. Employee #1 died.