BOARDWALK LOUISIANA MIDSTREAM, LLC

Incident Narrative

AT APPROXIMATELY 10:30 AM ON 7/29/18, THE OPERATOR NOTICED A RELIEF VALVE RELEASING TO THE FLARE. OPERATOR INVESTIGATED WHERE THE RELEASE TO THE FLARE WAS LOCATED. OPERATOR NOTICED THE FLARE BASE HAD IGNITED AND PRESSED THE MASTER SHUTDOWN FOR THE FACILITY AND ISOLATED THE RELIEF VALVE THAT FAILED. CONTACTED THE OFFICE OF EMERGENCY PREPAREDNESS (911) FOR RESPONSE. MADE NOTIFICATIONS TO ALL PERTINENT AGENCIES. IN REGARD TO QUESTION A14, ETHYLENE SERVICE RESTARTED ON 8/7/18 AT APPROXIMATELY 5:00 AM. ETHANE SERVICE WAS READY AT APPROXIMATELY 9 PM ON 8/16/18 BUT DID NOT START FLOWING UNTIL 8/18/18. ETHANE/PROPANE REMAINS OUT OF SERVICE. ESTIMATED IN SERVICE DATE FOR ETHANE/PROPANE IS 8/29/18. 11/29/18 UPDATED TO SUBMIT FINAL REPORT. 12/5/18 UPDATED IN RESPONSE TO PHMSA EMAIL. THE RESPONSES THAT HAVE CHANGED ARE BASED ON KNOWLEDGE GAINED FROM THE ROOT CAUSE ANALYSIS. PRIOR TO THE EVENT, AT AN UNDETERMINED TIME, THE SET PRESSURE OF THE RELIEF HAD BEEN LOWERED FROM THE PROPER SET POINT. FREQUENT LIFTING OF THE RELIEF VALVE OCCURRED AS A RESULT OF THE INCORRECT SET PRESSURE. THE REPETITIVE LIFTING OF THE RELIEF VALVE RESULTED IN DAMAGE TO THE SEATING O-RING IN THE PILOT OF THE VALVE. CONTRIBUTED BY AN IMPROPERLY SIZED O-RING IN THE MAIN VALVE BODY, THESE FACTORS COMBINED TO CAUSE THE RELIEF VALVE TO FAIL IN THE OPEN POSITION. WHEN THE RELIEF VALVE FAILED IN THE OPEN POSITION LIQUID ETHYLENE WAS THEN SENT TO THE FLARE WHICH THEN CAUGHT FIRE. THE RESPONSE TO PART G, 5A NEEDS CLARIFICATION BECAUSE AN APPROPRIATE RESPONSE IS NOT AN OPTION. INSPECTION AND TESTING OF RELIEF DEVICES IS COVERED IN BOARDWALK'S OQ PROGRAM BUT IT IS UNKNOWN WHO OR WHEN THE SET PRESSURE WAS LOWERED FROM THE PROPER SET POINT; THEREFORE, IT IS UNCLEAR WHO THE EMPLOYEE WAS OR IF THEY WERE QUALIFIED ON THIS TASK. 1-6-2020 UPDATED RELEASE VOLUME AND REPAIR COSTS TO SUBMIT FINAL REPORT. PERMANENT FLARE WAS IN-SERVICE ON DECEMBER 20, 2019. 1-10-2020 UPDATE FOLLOWING FURTHER INVESTIGATION. REPETITIVE LIFTING OF VALVE RESULTED IN DAMAGE TO SEATING O-RING IN PILOT OF THE VALVE WHICH CAUSED THE RELIEF VALVE TO DRIFT AND FAIL IN OPEN POSITION. IN ADDITION, THE FLARE KNOCK-OUT DRUM CONTAINED BRINE PREVENTING FULL DRUM CAPACITY AVAILABILITY CAUSING EXCESSIVE VOLUME TO BE SENT TO FLARE. WHEN THE RELIEF VALVE FAILED IN THE OPEN POSITION EXCESSIVE LIQUID ETHYLENE WAS THEN SENT TO THE FLARE WHICH THEN CAUGHT FIRE. CAUSE OF ACCIDENT HAS BEEN UPDATED FROM INCORRECT OPERATIONS TO EQUIPMENT FAILURE FOR THESE REASONS. WHILE INCORRECT OPERATIONS CONTRIBUTED TO THIS ACCIDENT, THE PRIMARY CAUSE WAS EQUIPMENT FAILURE. THE FACILITY WAS PREVIOUSLY UNDER PSM REGULATIONS AND THIS ACCIDENT OCCURRED DURING THE TRANSITION TO PHMSA REGULATIONS; THEREFORE, THIS WORK WAS NOT PERFORMED UNDER OQ.