ANR PIPELINE CO — Gas transmission and gathering — incident on 2012-03-21

Gas transmission and gathering incident. Reported cause: CORROSION FAILURE. Reported consequences: 0 fatalities, 0 injuries, 5000 NATURAL GAS released, $202,000 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: 20120039.

Operator ID: 405.

Reported incident date: 3/21/2012 6:15.

Cause detail: EXTERNAL CORROSION

Cause detail: THE PRODUCER OPERATOR AT SHIP SHOAL 204 CALLED IN TO REPORT A LEAK ON THE INCOMING ANR RISER. AFTER REPEATED CALLS BACK TO THE PRODUCER AND GETTING A PHOTOGRAPH FROM THE LOCATION, IT WAS ESTABLISHED THAT THE LEAK WAS ON THE INCOMING 12" 763 LATERAL. THE ATMOSPHERIC LEAK IS 9 FEET ABOVE THE WATERLINE UNDER A PIPE SUPPORT CLAMP WELDED TO THE LEG OF THE PLATFORM. THE ACCOUNT FROM THE PRODUCERS STATES THERE ARE NO ENVIRONMENTAL OR SAFETY ISSUES AT THIS TIME. THE PIPELINE WAS IMMEDIATELY ISOLATED WITH NOTIFICATIONS TO GAS CONTROL AND COMPLIANCE. REPAIR PLAN: ANR PIPELINE HAS SHUT IN ITS 12-IN. PIPELINE AND ALL PRODUCTION SOURCES UPSTREAM OF SS 204 BECAUSE OF A LEAK IN THE LINE. THE LEAK, ASSUMED TO BE THE RESULT OF CORROSION, IS ON THE 12-IN. RISER UNDER A RISER CLAMP AT THE +9 LEVEL. THIS ELEVATION IS A CRITICAL COMPONENT OF THE REPAIR. A REPAIR PLAN HAS BEEN DEVELOPED, WHICH INCLUDES THE INSTALLATION OF AN ENGINEERED, FULLY-WELDED SLEEVE. THE SLEEVE HAS NOW BEEN RECEIVED. WITH THE ADDITION OF THE SLEEVE, THE EXISTING RISER CLAMP HAS TO BE MODIFIED. FABRICATION OF THE NEW CLAMP WAS COMPLETED. A PRE-JOB WAS HELD WITH THE CONTRACTOR ON MAY 1. THE CONTRACTOR MADE FINAL PREPARATIONS FOR MOBILIZATION. MOBILIZATION WAS TARGETED FOR MAY 7, PENDING FAVORABLE WEATHER CONDITIONS. BECAUSE OF WEATHER DELAYS AND OTHER CONSTRUCTION AND FABRICATION DIFFICULTIES, THE REPAIR OF THE LINE WAS NOT COMPLETED UNTIL JULY 6, 2012.

PHMSA trend classification: significant incident, not serious.

PHMSA standardized cause: CORROSION — EXTERNAL.

PHMSA indexed costs: $247,000 reported total cost, $142,430.705 in 1984 dollars, $309,514.499 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.