CENTERPOINT ENERGY GAS TRANSMISSION — Gas transmission and gathering — incident on 2011-08-16

Gas transmission and gathering incident in AMBER, GRADY County, OK. Reported cause: EQUIPMENT FAILURE. Reported consequences: 0 fatalities, 0 injuries, 47000 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: 20110345.

Operator ID: 602.

Reported incident date: 8/16/2011 21:19.

Location detail: VALVE STATION

Cause detail: MALFUNCTION OF CONTROL/RELIEF EQUIPMENT

Cause detail: ON AUGUST 16, 2011 AT 20:45 A CEGT WESTERN REGION EMPLOYEE REPORTED TO CEGT SYSTEM CONTROL THAT A THIRD PARTY CONTACTED HIM ABOUT BLOWING GAS AT AMBER STATION. CEGT SYSTEM CONTROL CONTACTED AMBER FIELD PERSONNEL TO GO TO THE AMBER STATION AND CHECK OUT THE REPORT. AT 21:19 AN AMBER TEAM EMPLOYEE ADVISED CEGT SYSTEM CONTROL THAT THEY DO HAVE GAS BLOWING AT AMBER STATION AND THAT HE IS CURRENTLY UNSURE WHAT THE CAUSE IS. AMBER EMPLOYEES ADVISED THAT EMERGENCY PERSONNEL (FIRE AND POLICE) ARE ON SCENE. AT 21:30 AMBER EMPLOYEES CONTACTED THE CEGT SYSTEM CONTROL MANAGER AND INFORMED HIM OF THE SITUATION AT AMBER AND REQUESTED ASSISTANCE ON REPORTING THE INCIDENT. AT 21:40 AN AMBER EMPLOYEE CONTACTED SYSTEM CONTROL AND ADVISED THAT WHEN HE ARRIVED AT 21:15 GAS WAS STILL BLOWING. HE INFORMED SYSTEM CONTROL THAT HE MANIPULATED VALVES TO STOP THE RELEASE AT 21:29. HE ADVISED FIRE AND POLICE HAVE CLOSED THE ROAD OUTSIDE OF THE STATION. AT 22:41 CEGT SYSTEM CONTROL MANAGER CONTACTED PERSONNEL ON LOCATION AND CONFIRMED THAT THE ROAD CLOSURE WAS COUNTY ROAD 1280. THE ROAD WAS REOPENED WHEN THE STATION WAS SECURED AND FIRE AND POLICE WERE RELEASED. AMBER EMPLOYEES, ON THE SCENE, REPORTED THAT THE STATION ESD'ED AND WAS BLOWING GAS FROM THE SUCTION AND DISCHARGE LINES. EMPLOYEES OPERATED THE MAINLINE VALVE TO GET THE STATION BACK UNDER CONTROL. EMPLOYEES BEGAN GOING THROUGH THE YARD CHECKING THE SYSTEMS. THEY REPORTED THAT POWER AND COMMUNICATIONS WILL BE RESTORED WHEN THE STATION IS TAKEN OUT OF ESD MODE. A LIGHTENING STORM CAUSED AN ELECTRICAL SUPPLY PROBLEM THAT IN TURN CAUSED THE STATION TO ESD. THE STATION BACKUP GENERATOR DID NOT START. A POWER GAS VALVE FAILED AND DID NOT ISOLATE THE SUCTION AND DISCHARGE LINES, RESULTING IN GAS CONTINUING TO BLOW FROM THE MAINLINE TO THE STATION BLOW DOWN. ON AUGUST 17, 2011 AT 01:45 AMBER TEAM EMPLOYEES HAD THE REPAIRS MADE, RESUMED NORMAL OPERATIONS AT THE STATION AND LEFT THE LOCATION.

PHMSA trend classification: significant incident, not serious.

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

PHMSA indexed costs: $196,200 reported total cost, $136,298.639 in 1984 dollars, $172,785 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.