PIGGING INCIDENT

At approximately 8:00 a.m. on June 25, 2012, an employee was at the side of the pig launcher. The process was to purge the line of carbon gas with nitrogen. The nitrogen was pumped by a rig used to frac wells. The pump truck was capable of creating pressures which were several times greater than the launcher was designed and built for. 

The employee had several responsibilities some of which were to check the joints of black pipe feeding the nitrogen. This entailed pouring soap water on the joints and check for bubbles. He was also responsible for watching the pressure gauges on the launcher, getting the line purged so the pigging operation could start, and opening and closing the ball valves in the line t o provide for proper flow. He had just spoken to another employee while looking at the gauges on the launcher when the launcher ruptured. The ball valve leading to the 16-in. main line was not open. The pump truck had been pushing nitrogen into the small pig launcher instead of over three mile long pipeline. The gauges were not reading any pressure at all and when the pump truck kicked up the pressure, the launcher ruptured. The launcher was shot over 800 feet away. 

The main part of the vessel struck another employee killing him instantly. 

Source:Osha.gov