TENNESSEE GAS PIPELINE COMPANY

Incident Narrative

ON FEBRUARY 20, 2021, AT 16:30-HOURS, AN EMPLOYEE OF HOLLY SPRINGS GAS DEPARTMENT CALLED AN EMPLOYEE OF TENNESSEE GAS PIPELINE (TGP). THE CALLER INFORMED THE TGP EMPLOYEE OF A POTENTIAL INCIDENT WITH ONE OF THE TGP PIPELINES LOCATED IN MARSHALL COUNTY, MISSISSIPPI. THE EMPLOYEE IMMEDIATELY CALLED THE RESPONSIBLE OPERATIONS SUPERVISOR WHO IN TURN CALLED THE AREA MANAGER. THE AREA MANAGER DIRECTED THE OPERATIONS SUPERVISOR TO BEGIN CALLING AND MOBILIZING PERSONNEL TOWARDS THE HOLLY SPRINGS AREA. THE AREA MANAGER THEN CONTACTED TGP'S GAS CONTROL STAFF TO ASCERTAIN IF THEY HAD SEEN ANY PRESSURE CHANGES AND THEY HAD NOT. THE AREA MANAGER THEN CALLED THE HOLLY SPRINGS GAS DEPARTMENT WHO DIRECTED HIM TO THE MARSHALL COUNTY EMERGENCY MANAGEMENT AGENCY (EMA) STAFF. AT 16:56-HOUR, THE AREA MANAGER CONTACTED THE EMA FOR ANY INFORMATION AVAILABLE AND WAS MADE AWARE THAT THE EMA PERSONNEL HAD BLOCKED JACK THOMPSON ROAD AFTER EVACUATING SOME RESIDENCES IN THE AREA. TGP DIVISION STAFF AND THE LOCAL AREA MANGER INITIATED AN EMERGENCY RESPONSE LINE CONFERENCE CALL TO DISCUSS THE PENDING SITUATION AND ACTIONS CURRENTLY TAKEN. OUT OF ABUNDANCE OF CAUTION, TGP DECIDED TO CALL THE NRC AND REPORT THE POTENTIAL INCIDENT SITUATION. AT 18:25, A TGP FIELD EMPLOYEE ARRIVED AT MLV #68 TO INSTALL A MANUAL PRESSURE GAUGE IN ORDER TO IDENTIFY ANY PRESSURE ISSUES ON THE TGP LINE 100-1. SUBSEQUENTLY, AT 18:37, ANOTHER TGP FIELD EMPLOYEE ARRIVED AT MLV #67 TO INSTALL A MANUAL PRESSURE GAUGE TO IDENTIFY ANY PRESSURE ISSUES ON THE PIPELINE AS WELL. THESE RESPONSE TIMES WERE MUCH LONGER THAN NORMAL DUE TO INCLEMENT WEATHER AND VERY ICY ROAD CONDITIONS. AT 19:20-HOUR, FIELD PERSONAL CONFIRMED LINE 100-1 WAS LOSING PRESSURE AND PROCEEDED TO CLOSE BOTH MLV'S. AT 21:40 TGP REPORTED TO THE EMA THAT THE PRESSURE BETWEEN MLV #68 AND #67 WAS ZERO (0) PSIG. CONSEQUENTLY, THE EMA OPENED JACK THOMPSON ROAD, AND THE EVACUATED RESIDENTS RETURNED HOME. TGP STARTED THE REMEDIATION PROCESS FOR LINE 100-1 BY REPLACING THE SEGMENT CONTAINING THE LEAK. ON MARCH 1, 2021, THE REMOVED PIPE SPECIMEN CONTAINING THE LEAK BEGAN TRANSPORTATION BY TRUCK FROM THE HOLLY SPRINGS AREA TO BLADE ENERGY PARTNERS IN HOUSTON TX FOR LABORATORY ANALYSIS. IN ADDITION, THE VALVE SECTION OF LINE 100-1 RETURNED TO SERVICE AT 16:28-HOUR ON THE SAME DAY. THE INVESTIGATION WAS COMPLETED AND THE LABORATORY REPORT WAS LAST ISSUED ON JUNE 30, 2021. THE ANALYSIS RESULTED IN FINDING A LARGE THROUGH-WALL CRACK WITH A MAXIMUM CRACK OPENING OF 0.27 INCH AS FOUND ALONG THE CREST OF THE SECOND WRINKLE FROM THE UPSTREAM. THE LENGTH OF THE CRACK IS 4.1 FEET. THE FRACTURE SURFACE APPEARS TO BE CRYSTALLINE TYPE AND SHINY, WITH NUMEROUS FRESH RUST SPOTS. CHEVRON MARKS ARE OBSERVED WITH THEIR APEXES TOWARDS THE 1.5-FOOT LONG ORIGIN OF THE CRACKING. THE FAILURE APPEARS TO BE BRITTLE, LITTLE PLASTIC DEFORMATION WAS OBSERVED NEAR THE FRACTURE SURFACE. CHEMICAL ANALYSIS OF THE SAMPLE INDICATES THE MATERIAL COMPLIES WITH API REQUIREMENTS OF THE 1940'S. TENSILE TESTS SHOWS THE SAMPLE CONFORMS TO SMYS FOR X45 STEEL. ADDITIONAL ANALYSIS AND HARDNESS MEASUREMENTS FOUND DIFFERENCES, WHICH MAY BE CONTRIBUTED TO RE-HEATING THE PIPE BODY IN THE FIELD FOR THE BENDING DURING INSTALLATION. IT IS NOTED THE TEMPERATURE DROP DURING THE POLAR VORTEX IN THE WEEK OF FEBRUARY 14, 2021, COULD HAVE CONTRIBUTED TO THE FAILURE IN THE WRINKLE BEND AS WELL AS HARD SPOTS FROM RE-HEATING OF THE STEEL, WHICH INCREASED BRITTLENESS. CLEAVAGE CRACKING OCCURRED WHEN THE TEMPERATURE OF THE PIPE DROPPED NEAR OR BELOW FREEZING TEMPERATURE AND PROPAGATED RAPIDLY THROUGH THE WALL IN BRITTLE MANNER.