PAA NATURAL GAS STORAGE, LLC

Incident Narrative

APPROXIMATELY 2,484 MCF OF NATURAL GAS WERE RELEASED DUE TO A RUPTURE OF UNDERGROUND, COMPRESSOR STATION PIPING, WHILE PURGING. BLUEWATER GAS STORAGE, LLC OPERATORS REMOTELY SHUT-IN THE STATION. PERSONNEL ARRIVED ON SITE TO ASSESS DAMAGE AND PROPERLY ISOLATE THE STATION FOR CLEAN-UP AND REPAIRS. THE INCIDENT IS STILL UNDER INVESTIGATION TO DETERMINE THE ROOT CAUSE OF THE FAILURE. PIECES OF THE PIPING HAVE BEEN SENT FOR METALLURGICAL ANALYSIS. A SUPPLEMENTAL REPORT WILL BE SUBMITTED ONCE THE LAB RESULTS ARE RECEIVED. THE NATIONAL RESPONSE CENTER WAS NOTIFIED AND ASSIGNED REPORT NUMBER 1085180. SUPPLEMENTAL NARRATIVE: BASED ON THE RESULTS OF THE METALLURGICAL ANALYSIS, PLAINS HAS CONCLUDED THAT THE FAILURE WAS THE RESULT OF INTERNAL DETONATION THAT RESULTED IN SUDDEN OVER-PRESSURE OF THE PIPING AND OTHER COMPONENTS. AIR MOVERS HAD BEEN USED TO DE-ENERGIZE A PREVIOUSLY DAMAGED SECTION OF PIPELINE PRIOR TO THE INCIDENT OF JUNE 7, 2014. AS THE PIPELINE WAS BROUGHT BACK INTO SERVICE, THE AIR WAS DISPLACED BY FLOWING PIPELINE GAS TO AND THROUGH THE VECTOR STATION TO A SILENCER EQUIPPED VENT AT THE BOOSTER STATION. THIS WAS DONE TO MINIMIZE NOISE AND DISTURBANCE TO NEARBY RESIDENCES AND LIVESTOCK. IT APPEARS THAT THE AIR HAD NOT BEEN COMPLETELY ELIMINATED FROM ALL OF THE PIPING DURING THE STATION PURGING. AS THE VECTOR STATION WAS BEING PRESSURIZED TO THE NORMAL OPERATING CONDITIONS (PIPELINE PRESSURE), THE HEAT OF COMPRESSION COMBINED WITH THE RESIDUAL AIR INCREASED THE TEMPERATURE OF THE GAS TO AUTO IGNITE. THE SUBSEQUENT IGNITION OF THE FLAMMABLE GAS RESULTED IN A DETONATION/OVERPRESSURE INSIDE THE PIPE. THE PURGING PROCEDURES FOR THE PNGS PIPELINE AND THE BOOSTER STATION HAVE BEEN MODIFIED TO ADDRESS THE REMOVAL OF ALL AIR/OXYGEN FROM THE PIPELINE AND THE BOOSTER STATION EQUIPMENT PRIOR TO THE EQUIPMENTS RETURN TO SERVICE, WITH PARTICULAR ATTENTION FOCUSED IN ELIMINATING AIR FROM DEAD LEGS OF PIPING AND EQUIPMENT. THE STATION PIPING HAS BEEN REPLACED AND THE FACILITY WAS RESTARTED ON OCTOBER 28, 2014. THIS REPORT WAS UPDATED BASED ON INSTRUCTIONS RECEIVED FROM KYLE FRISKE WITH THE STATE OF MICHIGAN.