ONEOK WESTEX TRANSMISSION, LLC — Gas transmission and gathering — incident on 2016-12-26

Gas transmission and gathering incident in Not Within a Municipality, PECOS County, TX. Reported cause: EQUIPMENT FAILURE. Reported consequences: 0 fatalities, 0 injuries, 92600 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: 20170040.

Operator ID: 31531.

Reported incident date: 12/26/2016 12:05.

Location detail: ROADRUNNER CS

Cause detail: MALFUNCTION OF CONTROL/RELIEF EQUIPMENT

Cause detail: DURING AN IN-DEPTH GAS VOLUME REVIEW IN APRIL OF 2017 FOR THE ONEOK WESTEX PIPELINE SYSTEM, WESTEX IDENTIFIED A RELEASE (DESCRIBED BELOW) THAT OCCURRED IN DECEMBER 2016 AT THE ROADRUNNER COMPRESSOR STATION THAT WESTEX OPERATES. THIS WAS NOT INITIALLY RECOGNIZED AND REPORTED BY OPERATIONS AS AN EVENT THAT EXCEEDED 3MMCF, AND THEREFORE NEITHER A CALL TO NRC NOR A 30-DAY REPORT WAS MADE. BECAUSE THE DISCOVERY IN APRIL 2017 WAS FOR AN EVENT THAT OCCURRED IN DECEMBER 2016, AN NRC REPORT ALSO WAS NOT MADE IN APRIL 2017. ON 12/26/2016, AN O-RING IN A DISCHARGE PRESSURE RELIEF VALVE (PRV) ON COMPRESSOR UNIT 200 FAILED. THE FAILED O-RING DID NOT ALLOW THE VALVE TO SEAL PROPERLY AND CAUSED THE PRV TO ACTUATE. THE OPENED VALVE VENTED TO ATMOSPHERE UNTIL AN EMPLOYEE ARRIVED ON LOCATION ON 12/27/2016. THE RELIEF VALVE WAS CLOSED, THE O-RING WAS REPAIRED, AND IT WAS RETURNED TO SERVICE ON 12/28/2106.

PHMSA trend classification: significant incident, not serious.

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

PHMSA indexed costs: $237,514 reported total cost, $252,878.787 in 1984 dollars, $310,496.739 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.