ENABLE GAS TRANSMISSION, LLC — Gas transmission and gathering — incident on 2017-09-11

Gas transmission and gathering incident in BERNICE, CLAIBORNE County, LA. Reported cause: CORROSION FAILURE. Reported consequences: 0 fatalities, 0 injuries, 3695 NATURAL GAS released, $183,000 reported property damage. Operator-reported incident data submitted to PHMSA, generally within 30 days. Records may be supplemented or corrected and do not represent final agency causal findings.

Report number: 20170087.

Operator ID: 602.

Reported incident date: 9/11/2017 13:00.

Location detail: 1351+52

Cause detail: EXTERNAL CORROSION

Cause detail: WHILE PERFORMING A CLOSE INTERVAL SURVEY, AN ENABLE DIRECT ASSESSMENT (DA) CREW, DISCOVERED A LEAK ON LINE KT-1. UPON DISCOVERY, THE DA CREW NOTIFIED THE LOCAL ENABLE MIDSTREAM OPERATING PERSONNEL WHO ASSESSED THE SITUATION AND CONFIRMED THE LEAK TO BE ON KT-1 AT 13:38. THE ENABLE MIDSTREAM ON-CALL TEAM WAS NOTIFIED AND A NOTIFICATION CALL WAS PLACED TO THE NRC (NRC# 1189935 9/11/2017 14:14 CST). A 48 HOUR FOLLOW UP CALL (NRC#1190154) WAS PLACED ON 9/13/17 AT 11:11 CST. AT THE LEAK LOCATION, KT-1 CONSISTS OF GRADE B STEEL, 10.75, .188 W.T. PIPE. IT WAS INSTALLED IN CLAIBORNE PARISH LA IN 1942. LINE KT-1 WAS REPAIRED WITHOUT BEING TAKEN OUT OF SERVICE, BY PLACING STOPPLES BOTH UPSTREAM AND DOWNSTREAM OF THE LEAK SITE WITH A BYPASS. WHEN COMPLETED, THE LEAKING SECTION OF PIPE WAS REMOVED AND INVESTIGATED FURTHER. THE LEAK WAS FOUND TO BE LOCATED AT A CIRCUMFERENTIAL GIRTH WELD AT A CREEK CROSSING. IT HAS BEEN DETERMINED THAT SEVERAL FACTORS CONTRIBUTED TO THE LEAK ON KT-1. - THIS PIPE HAS BEEN PREVIOUSLY EXPOSED IN A SEASONAL CREEK CROSSING AND WAS SUBJECT TO ATMOSPHERIC CORROSION WHEN THE WATER LEVEL RECEDED. - LOW CATHODIC PROTECTION LEVELS WERE PREVIOUSLY FOUND DUE TO THE PRESENCE OF NEARBY DRESSER COUPLINGS. ALTHOUGH THESE LOW LEVELS OF CP WERE REMEDIATED, CORROSION HAS PREVIOUSLY OCCURRED. - IN 2012, THE CREEK CROSSING WAS REMEDIATED BY ADDING GROUND COVER. THE PIPE APPEARS TO HAVE EXPERIENCED STRESS FROM ADDED WEIGHT ABOVE PIPE GRADE AND LACK OF SUPPORT BELOW PIPE GRADE. THE REMAINING WALL THICKNESS AT THE GIRTH WELD APPEARS TO HAVE MECHANICALLY FAILED DUE TO THIS STRESS. A FINAL REPAIR COST CANNOT BE PROVIDED AT THIS TIME AND A SUPPLEMENTAL REPORT WILL BE SUBMITTED WHEN IT CAN BE DETERMINED.

PHMSA trend classification: significant incident, not serious.

PHMSA standardized cause: CORROSION — EXTERNAL.

PHMSA indexed costs: $194,180 reported total cost, $99,953.906 in 1984 dollars, $233,340.194 in current-year dollars.

PHMSA trend flags, standardized causes, and indexed costs are analytical fields added to operator-reported incident data. They do not represent final agency causal findings.