ONEOK GAS TRANSPORTATION, LLC

Incident Narrative

A LANDOWNER CALLED ONEOK GAS TRANSPORTATION GAS CONTROL TO REPORT A NATURAL GAS LEAK ON THE 24 INCH A-1300 NATURAL GAS PIPELINE NEAR THE LITTLE RIVER IN CLEVELAND COUNTY OKLAHOMA AT APPROXIMATELY 2330 HOURS ON THURSDAY JULY 15, 2010. ONEOK GAS TRANSPORTATION FIELD PERSONNEL WERE CONTACTED AND WERE ON THE SCENE BY 2355 HOURS. THERE WAS NO EXPLOSION, NO FIRE, NO INJURIES, AND NO DEATHS. THE LOCAL FIRE DEPARTMENT DID COME OUT TO THE SITE BUT DID NOT REMAIN ON SCENE. THE OKLAHOMA CORPORATION COMMISSION WAS NOTIFIED VIA TELEPHONE AT 0155 HOURS ON FRIDAY JULY 16, 2010. THE NATIONAL RESPONSE CENTER WAS CONTACTED AT 0257 HOURS ON FRIDAY JULY 16, 2010. THE NRC INCIDENT NUMBER IS 947893. THE A-1300 SEGMENT WHERE THE LEAK WAS LOCATED WAS ISOLATED BY CLOSING THE HIGHWAY 102 BLOCK VALVE AND THE LEXINGTON TAKE OFF VALVE. THE 13.3 MILES OF PIPELINE AROUND THE LEAK WAS ISOLATED BY 0227 HOURS ON FRIDAY JULY 16, 2010. THE LINE WAS ALLOWED TO BLOW DOWN AND THE SITE SECURED BY 0630 HOURS. THREE TV STATION CREWS WERE IN THE AREA FOR A SHORT PERIOD OF TIME AND THEY WERE BRIEFED ON THE SITUATION. APPROXIMATELY 10 FARM TAP CUSTOMERS WERE IMPACTED AND SERVICE TO THE TOWN OF LITTLE AXE, OKLAHOMA WAS PUT ON A CASCADE SYSTEM BY OKLAHOMA NATURAL GAS. CLOSER EXAMINATION OF THE INCIDENT SITE REVEALED A 30 FOOT DIAMETER CRATER WHERE A DRIP WAS LOCATED. REPAIR CONSISTED OF REPLACING 63 FEET OF A-1300 PIPELINE INCLUDING REMOVAL OF THE DRIP WITH 24 INCH 0.375 WALL THICKNESS X-60 GRADE PRETESTED PIPE. THE PIPELINE WAS PUT BACK INTO NORMAL SERVICE AT 1530 HOURS ON SATURDAY JULY 17, 2010. FIELD ASSESSMENT INDICATES A MATERIAL FAILURE OF THE 2 INCH BALON VALVE(S) LOCATED ON THE DRIP AS THE CAUSE OF THE INCIDENT. THESE VALVES WERE IN SERVICE IN A DAMP AND / OR WET ENVIRONMENT. IT APPEARS VALVE BODY AND / OR BOLT HAD CORROSION ISSUES WHICH LEAD TO VALVE FAILURE. THERE WAS ADEQUATE CATHODIC PROTECTION ON THE PIPELINE AND DRIP.