COLORADO INTERSTATE GAS CO — Gas transmission and gathering — incident on 2016-12-18

Gas transmission and gathering incident in Not Within a Municipality, BACA County, CO. Reported cause: NATURAL FORCE DAMAGE. Reported consequences: 0 fatalities, 0 injuries, 4000 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: 20170006.

Operator ID: 2564.

Reported incident date: 12/18/2016 9:15.

Location detail: MP 4, 3993FT.

Cause detail: TEMPERATURE

Cause detail: 12/18/2016, 08:35 HOURS MOUNTAIN, EMPLOYEE ARRIVED ON SITE AND BEGAN MAKING INSPECTIONS AND FOUND A RELIEF VALVE VENTING TO ATMOSPHERE. APPROPRIATE VALVES WERE IMMEDIATELY CLOSED AND COMPRESSOR UNIT WAS SHUT DOWN. VENTING WAS TERMINATED. INVESTIGATION FOUND THE GAS COOLER FOR UNIT CG5, WHICH IS COMPRESSING UNPROCESSED WET GAS, HAD FROZEN DURING THE EXTREME WEATHER TEMPERATURES OF -15 DEGREES CAUSING THE RELIEF VALVE TO OPEN. MAOP WAS NOT EXCEEDED. 12/18/2016, 09:15 HOURS MOUNTAIN, IT WAS DETERMINED THE GAS RELEASE VOLUME WAS A REPORTABLE VOLUME. WITH THE UNIT OFF LINE, A BYPASS LINE WAS OPENED TO ALLOW THE GAS COOLER TO THAW. PIPING AND EQUIPMENT WAS COVERED TO PROVIDE WINTER WEATHER PROTECTION TO ASSIST THAWING. THE UNIT CG5 WAS RETURNED TO SERVICE 12/19/2016 AT 12:00 HOURS MOUNTAIN. FURTHER ANALYSIS OF DATA INDICATES VENTING BEGAN 12/17/2016, 17:31 HOURS MOUNTAIN. AT THE TIME OF THIS EVENT AND PRIOR TO THE EVENT, THIS PORTION OF THE FACILITY WAS NOT CONTROL ROOM MONITORED. FOLLOWING THIS EVENT, CIG HAS INSTALLED MONITORING ON THE VENT OF THE RELIEF VALVE AND RELATED CONTROL ROOM ALARMS HAVE BEEN INSTALLED; ALL TO ALERT OPERATIONS PERSONNEL OF ANY FUTURE VENTING EVENT.

PHMSA trend classification: not significant, not serious.

PHMSA standardized cause: NATURAL FORCE DAMAGE — TEMPERATURE.

PHMSA indexed costs: $10,250 reported total cost, $10,771.286 in 1984 dollars, $13,379.101 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.