SABAL TRAIL TRANSMISSION, LLC (SPECTRA ENERGY PARTNERS, LP)

Incident Narrative

ON OCTOBER 22, 2022, AT APPROXIMATELY 9:12 AM EST, AN EMPLOYEE AT THE REUNION COMPRESSOR STATION IDENTIFIED GAS BLOWING THROUGH THE STATION BLOWDOWN STACK. THIS WAS NOT A PLANNED ACTIVITY AND INDICATED AN ISSUE. HE EXAMINED THE STATION AND IDENTIFIED AN ICE BUILDUP ON THE 2-INCH COMPRESSOR UNIT #1 LOADING VALVE. UNIT #1 WAS NOT IN OPERATION AT THE TIME BUT DID HAVE GAS AT A PRESSURE OF 150 PSIG LEAKING THROUGH THE VALVE INTO THE STATION BLOWDOWN SYSTEM. EARLIER UNDER NORMAL OPERATION UNIT #1 WAS SHUT DOWN TO SWITCH TO UNIT #2. THROUGH THIS PROCESS THE UNIT LOADING VALVE ON UNIT #1 FAILED TO TRAVEL TO THE FULLY CLOSED POSITION BUT DID INDICATE IT WAS CLOSED ON THE SYSTEM CONTROLS DUE TO A FAULTY LIMIT SWITCH. THE VALVE FAILING TO FULLY CLOSE ALLOWED FOR GAS TO VENT THROUGH THE STATION BLOWDOWN SYSTEM OVERNIGHT. THE RESTRICTED FLOW PATH CREATED A RESTRICTION AND PRESSURE DROP THAT CAUSED THE FORMATION OF ICE AT THE VALVE. THE FAULTY LIMIT SWITCH ON THE 2-INCH LOADING VALVE WAS ALSO REPLACED. UNIT #1 REMAINED OFF THROUGHOUT THIS TIME, UNIT #2 REMAINED RUNNING TO MEET ALL NEEDED CAPACITIES. THE FAILED COMPONENTS WERE REPLACED BEFORE RETURNING UNIT #1 TO NORMAL OPERATION. THE GAS LOSS BASED UPON THE RESTRICTION AND DURATION WAS CALCULATED TO BE 7.08 MMSCF. DECEMBER 15, 2022 PART A 4 - UPDATED TO REFLECT THE DATE AND TIME THE RELEASE STARTED PART G - CHANGED SUB-CAUSE FROM ""COMPRESSOR OR COMPRESSOR-RELATED EQUIPMENT"" TO ""NON-THREADED CONNECTION FAILURE - O-RING"" PART H UPDATED NARRATIVE