ANR PIPELINE CO

Incident Narrative

ON FEBRUARY 4, 2023, AN UNINTENTIONAL RELEASE OF 6.7 MILLION CUBIC FEET OF NATURAL GAS OCCURRED WHEN A 2-INCH 2-PIECE, THREADED VALVE PULLED APART, ON THE HIGH-PRESSURE DUMP LINE ON THE WELL HEAD SEPARATOR. A TECHNICIAN WAS NEARBY AT THE TIME OF THE RELEASE. NO INJURIES, NO FATALITIES AND NO DAMAGES WERE REPORTED. THE ISOLATION PLAN GENERATED FOR THE SECTION REQUIRED LATERAL VALVES TO BE CLOSED AND THE RELEASE WAS ISOLATED WITHIN 78 MINUTES. AFTER THE NATURAL GAS RELEASE, THERE WAS A SMALL RELEASE OF CRUDE OIL THAT IS A BYPRODUCT OF THE STORAGE WELL SYSTEM. A PRIMARY CAUSE OF THE EQUIPMENT FAILURE HAS YET TO BE DETERMINED AS THE INCIDENT IS CURRENTLY UNDER INVESTIGATION. A SUPPLEMENT REPORT WILL BE FILED UPON THE COMPLETION OF THE INVESTIGATION. UPDATE 7/3/2023 FAILURE INVESTIGATION FINAL SUMMARY REPORT THE RESULTS OF THE ANALYSIS INDICATE THAT THE BALL VALVE AND THREADED CONNECTION FAILED DUE TO EXPANSION OF THE FEMALE THREADED SECTION ON THE BALL VALVE, MOST LIKELY AS A RESULT OF WATER FREEZING INSIDE THE VALVE. THE EXPANSION LED TO PARTIAL DISENGAGEMENT OF THE MALE THREADS ON THE THREADED CONNECTION AND THE FEMALE THREADS ON THE VALVE BODY. AN AXIL TENSILE STRESS, LIKELY FROM THE FREEZING WATER ACTING ON THE VALVE AND THREADED CONNECTION RESULTED IN DEFORMATION OF THE OF MALE THREADS FROM THE THREADED CONNECTIONS. WHICH SEPARATED THE VALVE BODY FROM THE MALE THREADED CONNECTION.