BLACK HILLS ENERGY — Gas transmission and gathering — incident on 2017-12-08

Gas transmission and gathering incident in OZARK, FRANKLIN County, AR. Reported cause: CORROSION FAILURE. Reported consequences: 0 fatalities, 0 injuries, 33774 NATURAL GAS released, $1,415,284 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: 20180006.

Operator ID: 15359.

Reported incident date: 12/8/2017 6:25.

Location detail: UNKNOWN

Cause detail: EXTERNAL CORROSION

Cause detail: AT APPROXIMATELY 6:25 AM, THE 12" DISCHARGE PIPE FROM UNIT #13 & UNIT 14 BLEW OUT ON THE NORTHWEST CORNER OF THE COMPRESSOR BUILDING, FOLLOWED BY A LOUDER "BOOM" AND THEN A HUGE FIREBALL FOLLOWED. THERE WERE TWO COMPRESSOR OPERATOR WORKING (SCOTTY MAYFIELD AND TYLER DAHLEM), THAT WERE LOCATED JUST EAST OF THE BLOW OUT. THEY WERE NOT INJURED BUT WERE CLOSE ENOUGH TO FEEL THE PERCUSSION FROM THE BLAST. THEY IMMEDIATELY RAN TO THE MAIN ENTRY GATE OF THE STATION WHERE ONE OF THE THREE ESD ACTIVATION SITES ARE LOCATED AND ACTIVATED THE ESD FOR THE WHOLE STATION (6:33 A.M. ACCORDING TO THE HISTORY ON SCADA) SINCE IT WAS STILL UNCLEAR WHAT ALL WAS ON FIRE. THIS ONLY TOOK A COUPLE OF MINUTES. AFTER THE ESD WAS ACTIVATED THE BLOWING GAS AND FIRE IMMEDIATELY BEGAN TO DECREASE. THE OPERATORS DID NOT HAVE A CELL PHONE WITH THEM, SO SCOTTY, THE SENIOR OPERATOR INSTRUCTED TYLER, THE TRAINEE COMPRESSOR OPERATOR I, TO RUN OVER TO THE NEIGHBOR'S HOUSE AND CALL 911. SCOTTY WENT AROUND THE SOUTH FENCE OUT OF THE "HOT ZONE" TO GET BACK TO THE OFFICE AND THEN CALLED HIS SUPERVISOR, JUNIOR BOWEN AND JAMES DAHLEM. (JAMES DAHLEM AND TIM REYNOLDS WAS ALREADY AT THE OZARK OPERATIONS CENTER AND WENT IMMEDIATELY TO DRAKE STATION TO HELP. JUNIOR BOWEN WAS STILL AT HOME AND IMMEDIATELY HEADED THAT WAY WHILE CONTACTING 911, AMY YORK, KEITH MASINGALE, BJ WILLSON, GARY ENGLISH AND BRENT SAMPLEY) SCOTTY THEN CALLED GAS CONTROL AND RELAYED WHAT WAS HAPPENING AND ASKED THEM TO SHUT OFF THE WOOLSEY AND STOCKTON STORAGE. BY THIS TIME JAMES DAHLEM AND TIM REYNOLDS ARRIVED AND PARKED AT THE ENTRANCE AND STARTED MONITORING THE AIR FOR GAS LEL TO MAKE SURE IT WAS SAFE TO ENTER. THEY STARTED HELPING SCOTTY AND TYLER FIGURE OUT WHAT HAD ACTUALLY HAPPENED, HAD TO SHUT THE GAS OFF OF THE DUMP LINE AT UNIT #15 BECAUSE THE BLOWN OUT 12" LINE HAD BROKEN THE PLASTIC DUMP LINE AND IT WAS ON FIRE. BJ WILLSON, FIRE DEPARTMENT AND STATE POLICE ARRIVED RIGHT BEHIND JAMES DAHLEM AND WE ASKED THE POLICE AND FIRE DEPT. TO KEEP NON-BLACK HILLS PEOPLE AWAY. WE ALSO ASKED THE FIRE DEPARTMENT TO STAND-BY UNTIL WE HAD SECURED ALL BLOWING GAS. BRENT SAMPLEY ARRIVED AND THEN JUNIOR BOWEN ARRIVED. I (JUNIOR BOWEN) STARTED ACCESSING WHERE THE DAMAGE WAS AND BECAME THE ON-SEEN INCIDENT COMMANDER. I WAS COMMUTING VIA PHONE WITH GAS CONTROL AND THE ERL PHONE CALL TO COORDINATE GETTING GAS BACK INTO SERVICE AND GETTING CONSTRUCTION CREWS ON THE WAY TO HELP REPAIR THE BROKEN GAS LINE. AFTER WE WERE SURE ALL BLOWING GAS HAD BEEN SECURED I HAD THE COMPRESSOR OPERATORS START RETURNING UNITS BACK TO SERVICE. ACCORDING TO THE HISTORICAL DATA ON THE SCADA THE COMPRESSORS STARTED BACK IN SERVICE AT 8:14 AM. WE THEN ASKED THE FIRE DEPARTMENT TO COME INTO THE COMPRESSOR STATION AND PUT OUT THE SMALL FIRE (NONE GAS) ON THE #14 COMP. THE FIRE DEPARTMENT THEN WENT TO THE NORTH SIDE OF THE STATION OUTSIDE OUR PROPERTY AND PUT OUT A SMALL BRUSH FIRE. WITH THE DAMAGED PIPE ISOLATED THIS TOOK 5 COMPRESSORS OUT OF SERVICE. THE CONSTRUCTION CREWS REMOVED THE DAMAGED SECTION OF PIPE AND PIPELINE INTEGRITY GROUP ASSESSED THE REMAINING PIPE WE ABLE TO PUT THREE COMPRESSORS BACK INTO SERVICE. UNITS #13 AND #14 WERE NOT ABLE TO RETURN TO SERVICE BECAUSE OF EXTENSIVE DAMAGE. PHMSA/APSC REPORTING (PRESTON WALKER) O FIRST NOTIFICATION OF THIS INCIDENT TO MR. BOBBY HENRY (APSC) VIA E-MAIL @ 8:20 AM ON 12/08/2017. UPON APPROVAL I NOTIFIED THE NRC@ 8:55 AM AND TALKED TO BRENT AND GAVE A BRIEF DESCRIPTION OF THE INCIDENT. HE PROVIDED ME WITH A REPORT NUMBER# 1199139. I SENT ANOTHER E-MAIL TO MR. BOBBY HENRY @ 8:55 AM INFORMING HIM THAT THE NRC WAS NOTIFIED OF THIS INCIDENT. I RECEIVED A CALL FROM CHRIS RULE WITH THE NRC @ 9:50 AM AND HE WAS INQUIRING ABOUT AN UPDATE ON THE INCIDENT. I PROVIDED HIM WITH AN UPDATE AND HE STATED THAT HE WAS GOING TO CLOSE HIS REPORT.

PHMSA trend classification: significant incident, not serious.

PHMSA standardized cause: CORROSION — EXTERNAL.

PHMSA indexed costs: $1,529,448 reported total cost, $793,989.442 in 1984 dollars, $1,837,338.677 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.