TEXAS EASTERN TRANSMISSION, LP

Incident Narrative

ON JANUARY 21, 2024, AT APPROXIMATELY 10:30 A.M. ET, ENBRIDGE WAS NOTIFIED BY THE LOCAL SHERIFF DEPARTMENT THAT A STRANGE NOISE WAS ORIGINATING FROM THE REGULATOR STATION. THE RESPONDING TECHNICIAN DISCOVERED THAT A 3-INCH RELIEF VALVE WAS VENTING, EVEN THOUGH STATION PRESSURES WERE WITHIN NORMAL OPERATING RANGE BELOW THE MAXIMUM ALLOWABLE OPERATING PRESSURE (MAOP). AT APPROXIMATELY 10:45 A.M. THE RELIEF VALVE WAS ISOLATED ELIMINATING THE GAS FROM VENTING TO ATMOSPHERE. THE INITIAL INVESTIGATION DETERMINED THE RELIEF VALVE LIKELY BEGAN VENTING AROUND 4:30 A.M. ET. THE STATION IS LOCATED OFF A RURAL COUNTY ROAD WITH LIMITED TRAFFIC. THE NEAREST DWELLING WAS APPROXIMATELY 1/2 MILE FROM THE STATION. THE PRELIMINARY GAS LOSS CALCULATIONS WERE COMPLETED AT APPROXIMATELY 1:10 P.M. ET CONFIRMING THAT THE VOLUME WOULD LIKELY EXCEED THE REPORTING THRESHOLD. THE NRC WAS SUBSEQUENTLY NOTIFIED AT 1:55 P.M. ET. THE RESPONDING TECHNICIAN DETERMINED THAT THE RELIEF VALVE MALFUNCTIONED AS THE RESULT OF A BLOCKED PILOT LINE (I.E. FROZEN). THE TECHNICIAN REPAIRED THE PILOT AND PLACED THE RELIEF VALVE BACK IN SERVICE.