SUSQUEHANNA GATHERING COMPANY I, LLC

Incident Narrative

CDP 5, A MULTI-UNIT COMPRESSOR STATION IN GATHERING SERVICE, SUFFERED AN UNINTENTIONAL RELEASE OF NATURAL GAS ON THE MORNING OF MAY 18TH, 2018. THIS RELEASE WAS A RESULT OF A FAILURE OF A MECHANICAL RELIEF VALVE BETWEEN THE 2ND STAGE COMPRESSION AND THE COOLER ON UNIT #10. THE RELIEF VALVE FAILED SAFE AT A PRESSURE BELOW THE MAOP AND CONTINUED TO VENT GAS UNTIL THE UNIT WAS TAKEN OFF-LINE AND THE FLOW OF GAS WAS SECURED. THE EVENT BEGAN AT 03:03 HOURS AND LASTED UNTIL 06:51 HOURS. A LOCAL LAND OWNER REPORTED A NOISE COMPLAINT TO ANOTHER OPERATOR IN THE SHARED PIPELINE CORRIDOR, WHO IN TURN NOTIFIED DTE GAS CONTROL AT 06:03 HOURS. THE ON-CALL TECHNICIAN WAS DISPATCHED TO INVESTIGATE. UPON ARRIVAL, HE FOUND GAS BLOWING FROM A RELIEF VALVE ON UNIT #10, A SKID-MOUNTED RECIPROCATING COMPRESSOR. THE BLOWING GAS WAS SECURED BY SECURING THE INLET AND OUTLET VALVES ON THE UNIT. FOLLOW UP INVESTIGATIONS DETERMINED THAT THE RELIEF VALVE OPERATED BELOW IT'S SET POINT AND FAILED TO RESET. THE INCIDENT AND INVESTIGATION HAVE ALSO BEEN REPORTED TO THE PA PUBLIC UTILITIES COMMISSION. SECOND (48 HOUR) NRC REPORT NUMBER IS 1212719.