COLUMBIA GULF TRANSMISSION, LLC — Gas transmission and gathering — incident on 2016-11-25

Gas transmission and gathering incident in PATTERSON, ST. MARYS County, LA. Reported cause: CORROSION FAILURE. Reported consequences: 0 fatalities, 0 injuries, 982 NATURAL GAS released, $0 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: 20160096.

Operator ID: 2620.

Reported incident date: 11/25/2016 15:35.

Location detail: EL100-007

Cause detail: EXTERNAL CORROSION

Cause detail: ON NOVEMBER 24, 2016, AN OFFICER WITH THE LOCAL SHERIFF'S DEPARTMENT, CONTACTED COLUMBIA GULF TRANSMISSION, LLC (COLUMBIA) OPERATIONS PERSONNEL TO REPORT THE SIGHTING OF BUBBLES IN THE WAX LAKE OUTLET, ST. MARY PARRISH, IN THE STATE OF LOUISIANA. THE LOCATION OF THESE BUBBLES WERE EMANATING IN THE PROXIMITY OF COLUMBIA'S LINE EL-100 AS WELL AS OTHER PIPELINE OPERATORS IN THE REGION. DUE TO THE VARIOUS CROSSING OF PIPELINES ALONG THE RIVER, THE INITIAL ASSUMPTION WAS THAT THE SOURCE OF THESES BUBBLES OF UNINTENDED RELEASE WAS FROM ANOTHER PIPELINE OPERATOR OTHER THAN COLUMBIA. COLUMBIA OPERATES AND MAINTAINS A SYSTEM OF PIPELINES IN THE AREA. HOWEVER, IT WAS IDENTIFIED THAT THESE RIVER CROSSINGS WERE ABANDONED BACK IN THE EARLY 80'S AND WERE KEPT IN IDLE STATUS WITH ABOUT 32 PSIG BLANKET PRESSURE. UPON FURTHER INVESTIGATION AND DISCUSSIONS WITH OTHER OPERATORS WHO DO HAVE PIPELINES CROSSING THE RIVER, IT WAS RULED OUT THAT THEIR PIPELINES WERE NOT INVOLVED IN THIS RELEASE. HENCE, COLUMBIA IDENTIFIED THAT THESE BUBBLES WERE EMANATING FROM COLUMBIA'S LINE EL-100. THEREAFTER, THE NATIONAL RESPONSE CENTER (NRC) WAS NOTIFIED. THE REPORT TO THE NRC WAS MADE DUE TO THE EXPECTED COST TO ABANDON AND REMOVE LINE EL-100 SECTIONS OF PIPELINE CROSSING THE WAX LAKE OUTLET WOULD EXCEED $50,000. THE UNINTENDED RELEASE OF MATERIAL DID NOT EXCEED 3,000 MCF. PLANS WERE SET FORTH TO ABANDON AND REMOVE THIS SECTION OF PIPELINE IN A TIMELY MANNER. AFTER REMOVING THE FAILED SECTION OF LINE EL-100 FROM THE RIVER, AN ENGINEERING ASSESSMENT WAS CONDUCTED TO THE FAILED SECTION OF LINE EL-100 BY A METALLURGICAL FAILURE ANALYSIS CONSULTANT. THE ASSESSMENT CONCLUDED THAT THE FAILED SECTION WAS LIKELY SUBJECT TO LONGITUDINAL AND BENDING STRESSES IN CONJUNCTION WITH WALL LOSS DUE TO EXTERNAL CORROSION AT THE 6 O'CLOCK POSITION. THIS RIVER-CROSSING SECTION OF LINE EL-100 WILL NOT BE REPLACED OR RETURNED BACK TO SERVICE.

PHMSA trend classification: significant incident, not serious.

PHMSA standardized cause: CORROSION — EXTERNAL.

PHMSA indexed costs: $1,502,622 reported total cost, $749,107.506 in 1984 dollars, $1,841,374.026 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.