ONEOK WESTEX TRANSMISSION, LLC

Incident Narrative

ONEOK WESTEX TRANSMISSION WAS CONDUCTING ECDA CONFIRMATION DIGS ON 6 INCH DIAMETER PIPELINE 0420-000 ON MONDAY OCTOBER 15, 2012 UTILIZING A THIRD PARTY CONTRACTOR. THE CONTRACTOR HAD UNCOVERED THE PIPELINE AND TWO CONTRACTOR PERSONNEL WERE IN THE DITCH REMOVING THE OLD COATING IN PREPARATION FOR RECOATING THE PIPELINE. AT APPROXIMATELY 1015 HOURS, THE PIPELINE SPLIT OPEN LONGITUDINALLY RELEASING NATURAL GAS AND THE CONTRACTOR PERSONNEL IMMEDIATELY LEFT THE DITCH. THERE WAS NO FIRE, NO EXPLOSION, AND NO INJURIES. THE LOCAL SHERIFF WAS NOTIFIED AND THE 5-7 NEARBY STRUCTURES WERE EVACUATED AS A PRECAUTIONARY MEASURE ONLY. LINE PRESSURE AT THE TIME OF THE INCIDENT WAS 132 PSI WHICH WAS REDUCED TO 84 PSI TO MINIMIZE HAZARDS. INITIAL GAS LOSS CALCULATIONS AND ESTIMATED REPAIR COSTS WERE DETERMINED TO BE LESS THAN REPORTABLE LIMITS. THE RAILROAD COMMISSION OF TEXAS WAS PROVIDED A COURTESY CALL AT 1236 HOURS. FURTHER ASSESSMENT OF THE DAMAGED PIPE RESULTED IN A DECISION TO REPAIR VIA PIPE REPLACEMENT. THIS WOULD CAUSE A LOSS OF NATURAL GAS SERVICE DOWNSTREAM OF THE INCIDENT SITE TO THE TOWN OF STANTON WITH AN ESTIMATED 850 CUSTOMERS. THE NATIONAL RESPONSE CENTER WAS PROVIDED A COURTESY CALL AT 1454 HOURS (INCIDENT NUMBER 1027378) BASED ON THE LOSS OF SERVICE TO THE TOWN OF STANTON. THE RAILROAD COMMISSION OF TEXAS WAS NOTIFIED OF THE NRC INCIDENT NUMBER (TEXAS INCIDENT NUMBER 755). THE TOWN OF STANTON WENT DOWN AT 1430 HOURS IN PREPARATION FOR THE PIPE REPLACEMENT. REPAIRS WERE COMPLETED AND EVACUATED STRUCTURES RELEASED FOR OCCUPANCY BY 1900 HOURS THE SAME DAY. FULL SERVICE TO ALL CUSTOMERS AND APPROVAL TO RELIGHT OCCURRED AT 2145 HOURS. THE DELAY BETWEEN THE COMPLETION OF THE PIPE REPAIR AND RELIGHT WAS BECAUSE A SMALL 2 INCH METER HAD TO BE UTILIZED TO PRESSURE UP THE LINE AND IT TOOK SOME TIME TO ACHIEVE FULL LINE PRESSURE. FURTHER REFINED GAS LOSS CALCULATION RESULTS CAUSED THIS INCIDENT TO BECOME REPORTABLE BASED ON GREATER THAN 3 MMCF UNINTENTIONAL RELEASE OF NATURAL GAS. THE ENTIRE JOINT OF PIPE WHERE THE SPLIT OCCURRED WAS REPLACED (TOTAL OF 23.5 FEET). A FAILURE ANALYSIS IS IN PROCESS TO DETERMINE THE CAUSE OF THE RUPTURE. UPDATE: FAILURE ANALYSIS BY EXTERNAL THIRD PARTY WAS INCONCLUSIVE SO THE CAUSE OF THE LONG SEAM WELD FAILURE COULD NOT BE DETERMINED. IN ADDITION TO THE FAILURE ANALYSIS OF THE FAILED LONGITUDINAL SEAM, A SEGMENT FROM THE SAME JOINT OF PIPE ADJACENT TO THE SEAM FAILURE PORTION WAS HYDROTESTED TO FAILURE AT 1500+ PSIG. PART G5 AMENDED TO REFLECT THIS. THE INCIDENT COSTS AND AUTHORIZED SIGNATURE INFORMATION WERE ALSO UPDATED. THIS IS A SUPPLEMENTAL AND FINAL INCIDENT REPORT.