GAS TRANSMISSION NORTHWEST CORPORATION (GTN) — Gas transmission and gathering — incident on 2012-06-01

Current as of 2012-06-01 Government source

Pipeline and Hazardous Materials Safety AdministrationOfficial agency material

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Gas transmission and gathering incident in EASTPORT, BOUNDARY County, ID. Reported cause: INCORRECT OPERATION. Reported consequences: 0 fatalities, 0 injuries, 20500 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: 20120068.

Operator ID: 15014.

Reported incident date: 6/1/2012 11:00.

Location detail: 2.5

Cause detail: VALVE LEFT OR PLACED IN WRONG POSITION, BUT NOT RESULTING IN AN OVERPRESSURE

Cause detail: ON JUNE 1ST AT APPROXIMATELY 0930 PDT, A COMMUNICATIONS FAILURE WITHIN THE STATION 3 PROGRAMMABLE LOGIC CONTROLLER (PLC) CAUSED A STATION EMERGENCY SHUTDOWN (ESD). THE STATION VALVES IMMEDIATELY ATTEMPTED TO GO TO THEIR FAIL-SAFE POSITIONS. THE STATION B LINE SUCTION VALVE (VALVE 15) FAILED TO CLOSE AND ALLOWED GAS TO VENT THROUGH THE STATION BLOWDOWN SILENCER FOR APPROXIMATELY 90 MINUTES. GAS CONTROL FIRST NOTED AN ESD AT THE STATION AND THEN OBSERVED INDICATIONS THAT THE STATION MAY NOT HAVE BLOWN DOWN PROPERLY AND THAT IT WAS POSSIBLE THAT GAS WAS CONTINUING TO VENT. GAS CONTROL NOTIFIED LOCAL PERSONNEL AT THE SANDPOINT OFFICE AND TWO TECHNICIANS WERE DISPATCHED TO INVESTIGATE. THE TECHNICIANS ARRIVED AT STATION 3 AT APPROXIMATELY 1100 PDT. THEY DETERMINED THAT GAS WAS VENTING OUT THE BLOWDOWN SILENCER AND THAT VALVE 15 HAD NOT CLOSED. POWER GAS WAS RESTORED TO VALVE 15 WHICH ALLOWED THE VALVE TO TRAVEL CLOSED AND STOP THE VENTING OF GAS.

PHMSA trend classification: not significant, not serious.

PHMSA standardized cause: INCORRECT OPERATION — INCORRECT VALVE POSITION.

PHMSA indexed costs: $46,126 reported total cost, $38,242.043 in 1984 dollars, $47,540.773 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.

This material provides agency context. It does not replace binding regulatory text, and its legal effect depends on the underlying authority and facts.