TEXAS GAS TRANSMISSION, LLC

Incident Narrative

ON JUNE 18, 2019, TEXAS GAS TRANSMISSION'S GAS CONTROL RECEIVED A CALL ABOUT A POSSIBLE UNDERWATER PIPELINE LEAK IN THE MISSISSIPPI RIVER. AREA PERSONNEL ARRANGED FOR HELICOPTER, FLEW OVER AREA, AND CONFIRMED BUBBLES ON JUNE 19 AT APPROXIMATELY 09:10. NRC NOTIFICATION WAS MADE AND LINE WAS ISOLATED AND PRESSURED DOWN TO 0 PSIG. ON JUNE 21, A SONAR INSPECTION WAS DONE BUT WATER WAS AT A HIGH LEVEL WITH THE EAST BANK RIGHT-OF-WAY FLOODED AND INACCESSIBLE. DUE TO THE WATER MOVEMENT AND FLOODING IT WAS UNSAFE FOR DIVING OPERATIONS; INCIDENT SITE IS APPROXIMATELY 80 FEET BELOW WATER. MULTIPLE SONAR PASSES WERE RECORDED FROM APPROXIMATELY THE MIDDLE OF THE RIVER TOWARD THE WEST BANK WHERE THE SUSPECTED LEAK IS LOCATED. SONAR INDICATES THERE MAY BE A POSSIBLE EXPOSURE ON THE HELENA 12"" #1 LINE (HEL 12-1). IT IS LIKELY THAT THIS SECTION OF THIS LINE WILL BE ABANDONED. 9-6-19 EMAIL RECEIVED FROM PHMSA INDICATED THAT THE LATITUDE AND LONGITUDE INDICATED ON THIS REPORT DOES NOT FALL ON THE REFERENCED MAPPED PIPELINE. THIS PIPELINE IS UNDER THE MISSISSIPPI RIVER AND THE LOCATION PROVIDED IS WHERE BUBBLES WERE FOUND IN THE WATER; THIS IS THE MOST ACCURATE LATITUDE AND LONGITUDE AVAILABLE AT THIS TIME. THE LINE IS STILL SHUT IN. ALTHOUGH IT IS NOT KNOWN WHETHER THE INCIDENT OCCURRED ON THE PIPE OR A WELD, TO ACCOMMODATE PHMSA'S REQUEST FOR PIPE DATA, THE ANSWERS PROVIDED IN PART C HAVE CHANGED FROM ""ITEM INVOLVED IN INCIDENT = UNKNOWN,"" TO ""ITEM INVOLVED IN INCIDENT = PIPE."" REGARDING THE COSTS AND ABANDONMENT, COST HAS BEEN REDUCED FROM $5,000,000 TO $1,400,000 BECAUSE TEXAS GAS ORIGINALLY EXPECTED TO REPAIR THE LINE BUT INSTEAD WILL CHECK THE INTEGRITY OF THE HEL 12-2 (PARALLEL LINE) AND CONSIDER ABANDONING THE HEL 12-1; IF THIS APPROACH IS USED, PIG TRAPS MAY ALSO BE INSTALLED. CAUSE HAS NOT BEEN DETERMINED. THIS LINE IS OUT OF SERVICE AND THE LOCATION IS UNDER THE MISSISSIPPI RIVER. NO ADDITIONAL INVESTIGATION INTO CAUSE IS PLANNED. 11-14-19 UPDATE: TEXAS GAS WILL INVESTIGATE USING A DIVING TEAM. AT THIS TIME, THE CAUSE REMAINS UNKNOWN. ADDITIONALLY, TEXAS GAS PLANS TO PERFORM AN INLINE INSPECTION ON THE PARALLEL LINE. 3-25-2020 DIVERS WERE UNABLE TO IDENTIFY THE CAUSE OF THIS INCIDENT. THE PIPELINE INVOLVED IN THIS INCIDENT HAS NOW BEEN ABANDONED IN PLACE. A SECOND REDUNDANT PIPELINE IN THE SAME RIGHT-OF-WAY WAS MODIFIED AND INLINE INSPECTED TO ENSURE ITS INTEGRITY. INLINE INSPECTION SHOWED THIS PIPELINE IS FIT FOR SERVICE. SUBSEQUENTLY, GAS WAS RE-ROUTED TO THIS PIPELINE TO PROVIDE SERVICE. TO FURTHER INVESTIGATE THE CAUSE OF THIS INCIDENT WOULD REQUIRE PHYSICAL INSPECTION OF THE ABANDONED PIPELINE. DOING SO WOULD REQUIRE DIVERS TO JET OUT APPROXIMATELY 20 FEET OF SILT FROM THE RIVER BOTTOM. THIS ACTION WOULD NOT ONLY POSE SIGNIFICANT RISK TO PERSONNEL BUT COULD POSSIBLY JEOPARDIZE THE INTEGRITY OF THE SECOND PIPELINE NOW IN SERVICE.