EQUITRANS MIDSTREAM CORPORATION

Incident Narrative

AT 22:54 ON 7/4/2024, COMPLIANCE RECEIVED A CALL INDICATING THAT GAS WAS LEAKING PAST A CHECK VALVE ON THE DISCHARGE SIDE OF THE COMPRESSOR, WHICH CAUSED A RELIEF VALVE TO GO OFF, AND GAS TO MIGRATE TO A UNIT THAT HAD SHUT DOWN EARLIER IN THE DAY. THAT UNIT WAS SHUT DOWN FOR A DIFFERENT REASON UNRELATED TO THE CAUSE OF THIS INCIDENT. THE SHUT DOWN UNIT HAS A SAFETY FEATURE THAT VENTS ALL GAS THROUGH THE BLOWDOWN STACK. THE VENTING STARTED TO OCCUR AT APPROXIMATELY 4:30 AND STOPPED AT APPROXIMATELY 10:35, RESULTING IN AN APPROXIMATE LOSS OF 7,771 MCF OF GAS LOST (UPDATED FROM 7,500 MCF ON THE NRC REPORTS). WHEN OPERATIONS ARRIVED ON SITE, A BALL VALVE WAS SHUT UPSTREAM OF THE UNIT TO BLOCK ANY MORE GAS FROM BEING VENTED. ON MONDAY, 7/8, OPERATIONS INSPECTED THE CHECK VALVE AND FOUND A TEFLON BOLT STUCK IN THE VALVE. ONCE THE BOLT WAS REMOVED, THE VALVE WAS ABLE TO OPERATE NORMALLY. THE TEFLON BOLT HOLDS THE COMPRESSOR VALVE CAGES IN THE CYLINDER OF THE COMPRESSOR. THESE BOLTS ARE KEPT IN THE COMPRESSOR PER THE COMPRESSOR MANUFACTURER'S DESIGN. THE BOLTS ARE NOT MEANT TO BE REMOVED UNDER ANY CIRCUMSTANCE. GOING FORWARD, THE TECHNICIANS WILL INSPECT THE BOLTS DURING COMPRESSOR MAINTENANCE FOR SECURE FIT, WEAR, AND DAMAGE. THEY WILL BE REPLACED AS NEEDED. THE COMPANY WILL REVIEW ITS PROCEDURES TO DETERMINE IF ANY CHANGES ARE NECESSARY.