BLACK HILLS ENERGY

Incident Narrative

ON SUNDAY, JANUARY 8, 2012, AT APPROXIMATELY 9:00 AM THERE WAS A HOUSE EXPLOSION AND SUBSEQUENT FIRE LOCATED AT 104 WOOTEN STREET IN SUBLETTE, KS. TWO LOCAL COMPANY EMPLOYEES HEARD THE EXPLOSION FROM THEIR HOMES AND REPORTED TO THE SITE IMMEDIATELY. UPON ARRIVAL, BHE EMPLOYEES REQUESTED THE ASSISTANCE FROM LOCAL EMERGENCY MANAGEMENT PERSONNEL TO TREAT INJURIES AND ASSIST WITH EVACUATING THE SURROUNDING AREA. SEVEN PEOPLE WERE HOME AT THE TIME OF THE EXPLOSION AND FOUR WERE TAKEN TO THE HOSPITAL. BAR-HOLE TESTING WAS COMPLETED IN THE ALLEY ADJACENT TO THE INCIDENT SITE AND NATURAL GAS WAS DETECTED. BHE PERSONNEL TOOK PRECAUTIONARY MEASURES AND SHUT OFF THE EAST SIDE OF TOWN IN ORDER TO ISOLATE THE SECTION OF LINE. SERVICE WAS SHUT OFF TO APPROXIMATELY 250 CUSTOMERS. BHE PERSONNEL CONTINUED TO TEST FOR GAS READINGS IN THE ALLEY WHILE OTHER WORK WAS BEING PERFORMED. BHE PERSONNEL RESTORED GAS TO THE EASTERN PART OF THE SYSTEM AND BEGAN THE RE-LIGHTING PROCESS THAT EVENING. BHE PERSONNEL EXPOSED THE 2' COATED STEEL MAIN AT EACH END OF THE ALLEY AND CAPPED IT OFF. A PRESSURE TEST WAS THEN CONDUCTED ON THE MAIN AT UTILIZATION PRESSURE (9 PSI) AND THE LINE WOULD NOT PRESSURE UP. EXCAVATIONS BEGAN IN THE ALLEY NEAR THE SERVICE LINE AND TAP TO THE INCIDENT SITE AND THEN CONTINUED EAST ALONG THE MAIN. THE 2' MAIN WAS UNCOVERED AND DAMAGE WAS FOUND ON THE LINE APPROXIMATELY 15' FROM THE AFOREMENTIONED TAP. IT APPEARS THAT THE LINE HAD BEEN PREVIOUSLY DAMAGED BY A BACKHOE BUCKET. DAMAGE TO THE STEEL LINE WAS SEEN UNDER AND ALONG THE SIDES OF THE STEEL PIPE AND WHAT APPEARED TO BE A STRESS CRACK WAS NOTED ACROSS THE ENTIRE BOTTOM CIRCUMFERENCE OF THE PIPE. UPON FURTHER EXCAVATION WE DISCOVERED A SANITARY SEWER LATERAL CROSSING OUR LINE DIRECTLY UNDER THE DAMAGED AREA. THE DAMAGED SECTION OF PIPE WAS SECURED AND THEN REMOVED FROM THE SITE. THERE WERE NO SIGNS OF RECENT EXCAVATION IN THE AREA.