ETC TIGER PIPELINE, LLC

Incident Narrative

14:20 CST, MAY 20TH WHILE WORKING TO UPGRADE COMMUNICATIONS (SWITCHES) FOR BOTH SCADA AND LOCAL COMMUNICATIONS, THE ESD WAS ACTIVATED. DURING THE ESD TWO 42IN ESD (HEADER) VALVES REMAINED OPEN FOR 10 MINUTES ALLOWING LINE PRESSURE TO VENT THROUGH TWO 8IN VALVES. 14:30 CST, MAY 20TH ESD BLOW-OFF VALVES WERE MANUALLY CLOSED AND STATION WAS BY-PASSED. 15:30 CST, MAY 20TH LOCAL LAW ENFORCEMENT WAS NOTIFIED REPORT # 21-02113. 19:32 CST, MAY 20TH NRC NOTIFICATION WAS MADE NRC #1305609 ROUGH CALCULATION OF GAS VOLUME LOSS WAS COMPLETED BY REGULATORY. THIS NOTIFICATION WAS MADE ONCE THE GAS VOLUME WAS CALCULATED. MAY 21ST, DURING THE INVESTIGATION, IT WAS DISCOVERED THAT THE ACTUATOR ON THE FUEL GAS VALVE HAD MALFUNCTIONED INTERNALLY LEAVING THE VALVE IN THE CLOSED POSITION CAUSING THE PLC TO LOSE POWER THERE BY FORCING VALVES TO RETURN TO THEIR FAIL SAFE POSITION. SINCE THE VALVE CLOSED THERE WAS A REDUCTION IN POWER GAS TO ASSIST IN CLOSING THE ESD VALVES ON THE SUCTION AND DISCHARGE HEADERS. TO PREVENT THIS ISSUE FROM HAPPENING AGAIN, PERSONNEL HAVE SINCE TESTED AND ARE REPLACING ALL SOFT PARTS ON ALL OTHER ACTUATORS ON THE FUEL GAS VALVE ON FUEL SKIDS AT ALL COMPRESSOR STATIONS ON TIGER PIPELINE. 14:57 CST, MAY 21ST PHMSA 48 HOUR NRC NOTIFICATION WAS MADE NRC # 1305672, UPDATED THE GAS VOLUME, PHYSICAL ADDRESS, AND COORDINATES.