TRANSCONTINENTAL GAS PIPE LINE COMPANY — Gas transmission and gathering — incident on 2014-11-24

Gas transmission and gathering incident. Reported cause: CORROSION FAILURE. Reported consequences: 0 fatalities, 0 injuries, 50 NATURAL GAS released, $275,000 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: 20140138.

Operator ID: 19570.

Reported incident date: 11/24/2014 12:45.

Cause detail: INTERNAL CORROSION

Cause detail: 11-24-2014 TRANSCONTINENTAL'S (TRANSCO) SCHRIEVER OPERATIONS DISTRICT WAS CONTACTED BY COAST GUARD REGARDING BUBBLES THAT HAD BEEN SITED IN THE VICINTY OF TRANSCO'S FACILITIES (AREA/BLOCK SS 7). THE COORDINATES THAT WERE RECIEVED FROM THE COAST GUARD WERE PLOTTED BY THE SCHRIEVER OPERATIONS TEAM. TRANSCO'S 16" & 20" GAS GATHERING PIPELINES NEAR THE SUSPECT LEAK LOCATION WERE ISOLATED AND BLOWN DOWN. TRANSCO'S SUPPORT ENGINEER BEGINS THE PROCESS OF CONTACTING CONTRACTOR DIVE TEAMS AND EQUIPMENT TO INVESTIGATE AND REPAIR THE LEAK. ONCE THE BLOW DOWN OF THE LINES WAS COMPLETE THE 16" LINE WAS IDENTIFIED AS THE LEAKING LINE. 11-28-2014 THE DIVE TEAM BEGINS CLEANING THE LINE AND INITIATES THE INVESTIGATION. A UT READING OF THE LEAKING LINE IS PERFORMED BY THE DIVE TEAM. A REPAIR CLAMP HAS BEEN INSTALLED ON THE LEAK 11-30-2014. THE LINE IS REPRESSURED AND BACK IN FULL SERVICE 12-1-2014. THE RESULTS OF THE INVESTIGATION "SHOWN BELOW" DETERMINED THE MOST PROBABLE CAUSE OF THE LEAK ON THE 16" GAS GATHERING PIPELINE WAS DUE TO INTERNAL CORROSION. THE LOCATION OF THE LEAK ON THE PIPE WAS AT THE 7 O'CLOCK POSITION. THE UT INSPECTION RESULTS SHOWED NO EXTERNAL CORROSION OR DAMAGE ON THE PIPELINE. A LOW FLOW UNPROCESSED & UNDEHYDRATED GAS IS TRANSPORTED THROUGH THE PIPELINE SINCE 1990. TRANSCO DOES REVIEW EVERY INTERNAL CORROSION LEAK AND FOLLOWS IT'S POCEDURES TO PREVENT AND MITIGATE THESE TYPES OF ENVIROMENT. - THIS LINE HAS BEEN TRANSPORTING UNPROCESSED AND UNDEHYDRATED GAS SINCE 1990 AND HAS BEEN TREATED SINCE 1990 WITH CORROSION INHIBITORS & BIOCIDES. - SAMPLES ARE COLLECTED & RESIDUALS ARE MONITORED MONTHLY. - FIELD TECHS MONITOR THE CHEMICAL QUANTITIES AND CHEMICAL INJECTION PUMP OPERATIONS ON A MONTHLY BASIS. - TRANSCO'S CORROSION ENGINEERS AND SMES REVIEW EVERY INTERNAL CORROSION LEAK THAT OCCUR ON THIER SYSTEMS AND MAKE RECCOMENDATIONS AS NEEDED.

PHMSA trend classification: significant incident, not serious.

PHMSA standardized cause: CORROSION — INTERNAL.

PHMSA indexed costs: $298,160 reported total cost, $153,717.84 in 1984 dollars, $367,318.107 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.