COLUMBIA GAS TRANSMISSION CORP — Gas transmission and gathering — incident on 2011-02-22

Gas transmission and gathering incident in STRASBURG, SHENANDOAH COUNTY County, VA. Reported cause: EQUIPMENT FAILURE. Reported consequences: 0 fatalities, 0 injuries, 3890 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: 20110031.

Operator ID: 2616.

Reported incident date: 2/22/2011 0:55.

Cause detail: MALFUNCTION OF CONTROL/RELIEF EQUIPMENT

Cause detail: ON FEBRUARY 22, 2011 @ 00:50, THE 4-INCH ESD VENT VALVE ON THE STATION DISCHARGE LINE INADVERTENTLY OPENED. AT THIS TIME THE STATION FIRE VALVES WERE OPEN BUT NEITHER COMPRESSOR UNIT WAS RUNNING. AIR TEMPERATURE WAS ABOUT 25○F. THIS VALVE REMAINED OPEN FOR SEVERAL MINUTES AND CONTINUALLY VENTED GAS AS THE DISCHARGE PRESSURE AT THE STATION DROPPED. A COMPANY EMPLOYEE WHO LIVES NEAR THE STATION HEARD THE GAS BLOWING AND WENT TO FACILITY TO CHECK ON IT. UPON ARRIVAL HE FOUND THE OPEN VALVE AND ACTIVATED THE ESD SYSTEM TO ISOLATE THE STATION FROM THE PIPELINE AND TO ALLOW THE STATION PIPING TO COMPLETELY BLOWDOWN. THE EVIDENCE OF WATER AND OTHER SOLID MATERIAL IN THE ESD TRIGGER AIR SUPPLY PIPING HAD INITIATED (AS A RECOMMENDATION) A CREATION OF A WORK MANAGEMENT PREVENTIVE MAINTENANCE WORK ORDER, TO BLOW ANY DEBRIS FROM THE ESD TRIGGER AIR LINES TO ALL OF THE FIRE VALVES AND VENT VALVES WHEN THE ESD SYSTEM IS LOADED AT THE BEGINNING OF EACH OPERATING SEASON.

PHMSA trend classification: not significant, not serious.

PHMSA standardized cause: EQUIPMENT FAILURE — MALFUNCTION OF CONTROL/RELIEF EQUIPMENT.

PHMSA indexed costs: $1,802 reported total cost, $1,264.281 in 1984 dollars, $1,552.345 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.