ONEOK GAS STORAGE, LLC — Gas transmission and gathering — incident on 2011-05-24

Gas transmission and gathering incident in EDMOND, LOGAN County, OK. Reported cause: NATURAL FORCE DAMAGE. Reported consequences: 0 fatalities, 0 injuries, 42887.4 NATURAL GAS released, $126,321 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: 20110199.

Operator ID: 31532.

Reported incident date: 5/24/2011 16:55.

Cause detail: OTHER NATURAL FORCE DAMAGE

Cause detail: AN EF-5 TORNADO CAME THROUGH THE ONEOK GAS STORAGE'S EDMOND STORAGE FACILITY LOCATED NORTH OF EDMOND, OKLAHOMA, AT APPROXIMATELY 1655 HOURS ON 24MAY2011. A ONEOK EMPLOYEE WHO LIVED NEAR THE INCIDENT SITE NOTIFIED THE EDMOND STORAGE SUPERVISOR AFTER THE TORNADO STRUCK THAT THERE WAS LEAKING GAS. ONEOK PERSONNEL WERE DISPATCHED AND VERIFIED A LEAK CAUSED BY A MISSING VENT STACK ON THE F-352 PIG LAUNCHER LOCATED APPROXIMATELY 1.5 MILES WEST OF THE EDMOND STORAGE COMPRESSOR STATION (DAMAGE INCLUDED MISSING VENT STACK AND FENCING). FURTHER FIELD INVESTIGATION REVEALED OTHER DAMAGE (MEASUREMENT, CATHODIC PROTECTION, FENCING, PIPE GUARDS, CORROSION COUPON HOLDERS, ELECTRIC SERVICE) AT FOUR STORAGE WELLS (BRIDAL H-1, BRIDAL H-2, MESSENBAUGH S-1, MESSENBAUGH S-2). THE LINES TO THE LAUNCHER AND ALL FOUR WELLS WERE SHUT IN AND BLOWN DOWN BY 1905 HOURS. THE OKLAHOMA CORPORATION COMMISSION WAS NOTIFIED OF THE DAMAGE AT 2130 HOURS ON MAY 24, 2011. REPAIRS HAVE BEEN COMPLETED ON THE LAUNCHER AND THE PIPELINE HAS BEEN RESTORED TO SERVICE. ALL WELLS ARE BACK IN SERVICE BUT FACILITY REPAIRS ARE ONGOING. PHMSA WAS NOTIFIED AT 1545 HOURS ON JUNE 6, 2011 AFTER THE VOLUME OF UNINTENTIONAL GAS LOST WAS DETERMINED TO BE GREATER THAN 3 MCF. UPDATE: ALL FACILITY REPAIRS ARE COMPLETED AND ALL INCIDENT GAS VOLUMES AND COSTS UPDATED APPROPRIATELY. FINAL UPDATE: ONLY CHANGE WAS TO MAKE THIS THE FINAL INCIDENT REPORT.

PHMSA trend classification: significant incident, not serious.

PHMSA standardized cause: NATURAL FORCE DAMAGE — OTHER NATURAL FORCE DAMAGE.

PHMSA indexed costs: $307,011 reported total cost, $194,355.293 in 1984 dollars, $322,981.824 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.