ENOGEX LLC — Gas transmission and gathering — incident on 2012-04-04

Gas transmission and gathering incident in PERRY, NOBLE County, OK. Reported cause: OTHER INCIDENT CAUSE. Reported consequences: 0 fatalities, 0 injuries, 3368 NATURAL GAS released, $0 reported property damage. Operator-reported incident data submitted to PHMSA, generally within 30 days. Records may be supplemented or corrected and do not represent final agency causal findings.

Report number: 20120045.

Operator ID: 26330.

Reported incident date: 4/4/2012 2:00.

Cause detail: MISCELLANEOUS

Cause detail: ON THE MORNING OF APRIL 3, 2012 A DISRUPTION OF PURCHASED POWER SERVING THE PERRY COMPRESSOR STATION AUTOMATICALLY ACTIVATED THE COMPRESSOR STATION EMERGENCY SHUTDOWN (ESD) SYSTEM, WHICH IS DESIGNED IN ACCORDANCE WITH 49 CFR PART 192.167. THE ESD SYSTEM IS DESIGNED TO ISOLATE THE COMPRESSOR STATION FORM THE INCOMING AND OUTGOING PIPELINES AND VENT ALL GAS INSIDE THE STATION TO A SAFE LOCATION. THE STATION INLET ESD VALVE FAILED TO CLOSE DUE TO A BLOCKAGE IN THE ESD VALVE ACTUATOR EXHAUST TUBING. THE BLOCKAGE, WHICH WAS IDENTIFIED AS POLLEN DEPOSITED BY INSECTS INSIDE THE TUBING, PREVENTED THE OPERATING PRESSURE INSIDE THE SPRING OPERATED VALVE ACTUATOR FROM VENTING TO ATMOSPHERE, THUS PREVENTING THE VALVE FROM OPERATING PROPERLY. THE ESD SYSTEM VENT VALVES DID OPERATE PROPERLY, THEREBY VENTING 3,368 MCF OF NATURAL GAS TO THE ATMOSPHERE UNINTENTIONALLY. GAS CONTROL DISPATCHED COMPANY PERSONNEL TO THE COMRPESSOR STATION. THE COMPRESSOR STATION WAS ISOLATED FORM THE PIPELINE VIA A MANUAL ISOLATION VALVE. THE NATURAL GAS REMAINING INSIDE THE STATION ESD VENT PIPING WAS THEN QUICKLY VENTED TO THE ATMOSPHERE. THE BLOCKAGE WAS REMOVED FROM THE ACTUATOR EXHAUST PORT TUBING AND THE STATION INLET ESD VALVE WAS RETURNED TO NORMAL OPERATION. THERE WAS NO DAMAGE TO THE ACTUATOR OR ESD VALVE. UPDATE MARCH 5, 2013: COMPLETED SECTION E.5.F.

PHMSA trend classification: not significant, not serious.

PHMSA standardized cause: ALL OTHER CAUSES — MISCELLANEOUS.

PHMSA indexed costs: $6,230 reported total cost, $5,202.643 in 1984 dollars, $6,388.055 in current-year dollars.

PHMSA trend flags, standardized causes, and indexed costs are analytical fields added to operator-reported incident data. They do not represent final agency causal findings.