Abstract: Employees #1 and #2 were in a ditch, cold cutting a natural gas pipeline to install a new valve setting. When they broke the shell of the pipe, the nitrogen that was used to purge the pipe sprayed out under pressure. Employees #1 and #2 left the ditch, but later went back in while the nitrogen was still spraying out. They were replacing the valve setting when the pipe exploded violently. Employee #1 was thrown approximately 75 ft down the ditch and was covered with gravel, dirt, and rocks. Employee #2 was thrown about 20 ft and slammed into a segment of pipe. Both were killed. A lockout device located approximately six to seven miles to the northwest of the site had not been removed before the employees cut into the pipeline. With the lockout device in place, the line remained pressurized from the firegate valve to the site of the incident. The foreman who had originally applied the lockout device had to leave the area and did not inform anyone that the firegate was locked out. Also, because the acting lead person wanted to complete the test before leaving the area, Employees #1 and #2 were instructed to go back into the ditch near the cut in the line before it could be verified that the line was depressurized.