EL PASO NATURAL GAS CO

Incident Narrative

AT 9:28 AM (MST) EL PASO NATURAL GAS COMPANY, LLC (EPNG) NAVAJO COMPRESSOR STATION C PLANT EXPERIENCED AN EMERGENCY SHUTDOWN (ESD). EPNG GAS CONTROL DISPATCHED A TECHNICIAN TO THE NAVAJO COMPRESSOR STATION WHO ARRIVED AT 10:30 AM (MST). UPON ARRIVAL THE TECHNICIAN DISCOVERED GAS VENTING THROUGH A VENT VALVE. AT 10:32 AM (MST) THE TECHNICIAN PROCEEDED TO MANUALLY CLOSE THE DISCHARGE VALVE WHICH STOPPED THE UNINTENTIONAL RELEASE OF GAS. THE ACTIVATION OF THE ESD WAS DUE TO A FIRE EYE MALFUNCTION. UPON ACTIVATION OF THE ESD THE INLET AND DISCHARGE VALVES ARE DESIGNED TO TURN TO THE CLOSED POSITION AND THE GAS REMAINING IN THE PLANT IS VENTED TO ATMOSPHERE, HOWEVER IN THIS EVENT THE DISCHARGE VALVE DID NOT CLOSE. THE DISCHARGE VALVE IN THIS SYSTEM HAD UNDERGONE AN ESD MAINTENANCE TEST ON MARCH 6TH, 2019 AND THE VALVE HAD CLOSED AS DESIGNED. THE DISCHARGE VALVE IS ACTUATED WITH POWER GAS BUT DURING THE INVESTIGATION IT WAS FOUND THAT THE ASSOCIATED POWER GAS SUPPLY VALVE WAS IN THE CLOSED POSITION. CONSEQUENTLY, WHEN THE ESD SYSTEM WAS ACTIVATED THERE WAS NO POWER GAS FEEDING THE DISCHARGE VALVE ENABLING IT TO TURN TO THE CLOSED POSITION. THIS RESULTED IN THE DISCHARGE VALVE REMAINING OPEN ALLOWING GAS FROM THE DISCHARGE SIDE OF THE PLANT TO CONTINUE TO VENT. THE DISCHARGE VALVE REMAINED OPEN UNTIL IT WAS MANUALLY SHUT BY THE TECHNICIAN. THE 48-HR NRC INCIDENT REPORT NUMBER IS 1249752. THE CONFIRMED DISCOVERY TIME OF THE INCIDENT WAS 10:30 AM (MST).