COLUMBIA GULF TRANSMISSION CO

Incident Narrative

ON JANUARY 24, 2013, COLUMBIA GULF TRANSMISSION COMPANY (COLUMBIA) WAS ADVISED THAT SHEEN APPEARED ON THE WATER IN THE AREA OF ITS ABANDONED LINE BW-200. BECAUSE THERE ARE MULTIPLE FOREIGN PIPELINES IN THAT AREA, IT WAS NOT IMMEDIATELY CLEAR TO WHICH LINE THE SHEEN RELATED. NEVERTHELESS, OUT OF CAUTION, COLUMBIA'S ENVIRONMENTAL PERSONNEL REPORTED THE SHEEN TO THE NRC REPORT NO. 1036464 AND CERTAIN LOUISIANA AGENCIES AS APPROPRIATE. COLUMBIA CONTINUED ITS INVESTIGATION TO DETERMINE IF THERE WAS IN FACT A LEAK AND IF SO WHETHER SUCH LEAK WAS IN A COLUMBIA GULF OWNED PIPELINE. ATTENTION FOCUSED ON A SMALL AMOUNT OF BUBBLES REACHING THE SURFACE. FOREIGN PIPELINES WERE BLOWN DOWN BY THEIR RESPECTIVE OPERATORS. FEW BUBBLES REMAINED, ENABLING COLUMBIA TO CONCLUDE THAT ITS ABANDONED LINE BW-200 COULD BE THE SOURCE OF THE BUBBLES. NITROGEN WAS INJECTED INTO THE PIPELINE IN ORDER TO LOCATE PRECISELY IF THERE WAS A LEAK AND WHERE THE LEAK WAS LOCATED. DIVERS WERE MOBILIZED TO EXCAVATE THE PIPELINE, LOCATE THE LEAK ON THE PIPELINE SURFACE AND IMPLEMENT REPAIRS. THIS REPAIR CONSISTED OF INSTALLING A 36-IN PRE-TESTED BOLT-ON CLAMP WHERE COLUMBIA TREATED THIS PIPELINE AS AN ACTIVE LINE RATHER THAN ABANDONED. FOLLOWING THE REPAIR, NO FURTHER BUBBLES WERE PRESENT FROM THIS LOCATION. WHILE TESTING THE REPAIR TO ENSURE ITS EFFECTIVENESS, SOME BUBBLING WAS NOTICED APPROXIMATELY 80 FEET SOUTH OF THE REPAIR LOCATION NEAR BUT NOT NECESSARILY ON THE SAME PIPELINE. THERE WAS NO EVIDENCE OF ANY SUBSTANCE BEING RELEASED WITH THOSE BUBBLES. THIS SECOND AREA WAS EXCAVATED AND NITROGEN INJECTED INTO THE LINE. THE PRESSURE WAS HELD FOR 2 HOURS WITH NO EVIDENCE OF BUBBLING AND NO PRESSURE DROP. THE DIVER DID NOT OBSERVE ANY EVIDENCE OF A LEAK. BOTH EXCAVATION AREAS WERE BACKFILLED. COLUMBIA WILL RE-INSPECT THE AREA AFTER ALLOWING TIME FOR NORMAL SETTLING IN THE EXCAVATED AREAS (AT BOTH SITES) TO ENSURE THERE IS ADEQUATE COVER OVER THE PIPELINE AS WELL AS TO ENSURE THE EFFECTIVENESS OF THE PREVIOUS SHEEN REMOVAL EFFORTS. ORIGINAL PLANS WERE TO PIG THE LINE IN 2013. FOLLOWING ANALYSIS OF THE SITUATION, A DECISION WAS MADE NOT TO PIG AT THAT TIME. THE PIPELINE IS BEING MONITORED TO ENSURE THE CONDITIONS WHICH LED TO THE EMERGENCY RESPONSE ARE NOT REPEATED. IF CONCERNS ARISE BASED ON COLUMBIA GULF INSPECTIONS, PIPELINE OPERATIONS PERSONNEL WILL TAKE NECESSARY ACTIONS TO ADDRESS THE SITUATION, WHICH MAY INCLUDE PIGGING.