DOMINION ENERGY OHIO

Incident Narrative

ON 11-15-19 DOMINION WAS NOTIFIED BY THE LOCAL FIRE DEPARTMENT AT 1:01 AM OF A FIRE ON OR NEAR THE OPERATORS PIPELINE. DEO CONFIRMED THAT THE FIRE WAS OCCURRING ON ITS FACILITIES AT APPROXIMATELY 1:45 AM BASED ON COMMUNICATIONS WITH FIELD OPERATIONS AND GAS CONTROL. THE LINE WAS ISOLATED AND FIRE EXTINGUISHED AT 3:30AM. THERE WERE NO INJURIES, FATALITIES, OR STRUCTURE DAMAGES. THE 30 INCH STEEL MAIN HAD BEEN RECENTLY INSTALLED, AND THE LOCATION OF THE RELEASE WAS AT A ROAD CROSSING AUGURED UNDER THE ROAD INSTALLED AT APPROXIMATELY 14.5FT. DEEP ON THE SOUTH END TO APPROXIMATELY 21FT. DEEP ON THE NORTH END. ON 11-24-19 THE FAILED SECTION WAS REMOVED AND CONFIRMED THAT THE RELEASE OF GAS HAD OCCURRED AT A GIRTH WELD FAILURE. IN COOPERATION WITH THE PUCO, THE FAILED SECTION OF THE PIPELINE (ALONG WITH ADDITIONAL SECTIONS IMMEDIATELY UPSTREAM AND DOWNSTREAM OF THE SECTION CONTAINING ADDITIONAL WELDS FOR TESTING) WERE EXTRACTED AND RETAINED BY DNV FOR METALLURGICAL ANALYSIS. THE PROTOCOLS FOR THE ANALYSIS WERE REVIEWED AND APPROVED BY DEO AND THE PUCO. DNV ISSUED ITS FINAL METALLURGICAL ANALYSIS REPORT ON 5-18-20, AND DEO HAS CONCLUDED ITS REVIEW OF THE INCIDENT. ANALYSIS OF THE INCIDENT INDICATES THAT THE FAILURE OCCURRED AS A RESULT OF AXIAL BENDING STRESSES ON THE PIPE STRING, LIKELY DUE TO THE PRESENCE OF A CAVERN OR VOID IN THE ROCK FORMATION THROUGH WHICH THE AUGER PASSED, WHICH CAUSED THE AUGER TO VEER OFF COURSE. THE BENDING STRESS CAUSED THE FIELD GIRTH WELD LOCATED AT THE EDGE OF THE CAVERN TO FAIL, PRIMARILY IN DUCTILE OVERLOAD. THIS ANALYSIS ALSO DETERMINED THAT A PRE-EXISTING HYDROGEN CRACK (FORMED PRIOR TO THE FINAL FAILURE) AND WELDING DEFICIENCIES CONTRIBUTED TO THE ELEVATED STRESS STATE ON THE GIRTH WELD.