COLUMBIA GAS OF OHIO INC

Incident Narrative

ON FEBRUARY 25, 2018, RICHLAND COUNTY 911 REPORTED A FIRE AND POSSIBLE EXPLOSION AT 613 FLEMING FALLS ROAD IN MANSFIELD, OHIO AT 12:33 AM TO COLUMBIA GAS OF OHIO, INC (""COLUMBIA""). COLUMBIA'S SERVICE TECHNICIAN WAS DISPATCHED AT 12:42 AM AND ARRIVED ON SITE AT 01:15 AM AND FOUND THAT GAS HAD BEEN SHUT OFF AT THE METER VALVE BY THE FIRE DEPARTMENT. ADDITIONAL COLUMBIA RESOURCES ARRIVED ON SITE AT 1:50 AM TO ASSIST IN THE RESPONSE TO THE INCIDENT. COLUMBIA EMPLOYEES SET UP A PERIMETER AND EVACUATED THE NEIGHBORING HOME AT 605 FLEMING FALLS WHERE NATURAL GAS READINGS WERE DISCOVERED IN THE BASEMENT. COLUMBIA VERIFIED THAT THE SYSTEM PRESSURE WAS WITHIN THE MAOP ESTABLISHED FOR THAT SYSTEM AND THAT ODORANT WAS COMPLIANT WITH STATE AND FEDERAL REQUIREMENTS. ELECTRIC METERS WERE REMOVED TO ELIMINATE SOURCES OF IGNITION AND COLUMBIA BEGAN TO SEARCH FOR LEAKAGE AND ENSURE SAFETY. THE NIGHT OF THE INCIDENT THERE WAS A TREMENDOUS AMOUNT OF RAIN THAT CAUSED THE SANITARY LIFT PUMPS TO FAIL AND MAY HAVE POTENTIALLY PUSHED A SLUG OF SEWER GAS INTO THE BASEMENT VIA FLOOR DRAINS THAT WERE FOUND TO BE TIED DIRECTLY TO THE SANITARY SEWER FOR 605 AND 613 FLEMING FALLS RD. THE EXPLOSION THAT OCCURRED APPEARS TO BE A LOW LEVEL EXPLOSION. COLUMBIA LOCATED AND REPAIRED A TOTAL OF FOUR LEAKS OF WHICH WE BELIEVE TO BE NON-CAUSAL. THE CLOSEST BEING APPROXIMATELY 290' AWAY AND THE FURTHEST BEING APPROXIMATELY 1300' AWAY FROM THE INCIDENT. THE SURFACE LEVEL OF THE SOUTH SIDE OF THE STREET IS APPROXIMATELY 12' LOWER THAN THE SURFACE LEVEL OF THE STREET IN FRONT OF THE INCIDENT SITE. COLUMBIA CREATED A TEMPORARY BYPASS TO KEEP CUSTOMERS IN SERVICE, ABANDONING APPROXIMATELY 775' OF BARE STEEL HIGH PRESSURE MAINLINE ON THE SOUTH SIDE OF THE STREET. COLUMBIA PRESSURE TESTED THE BARE STEEL MAIN ON THE SOUTH SIDE OF THE STREET ALONG WITH THE SERVICES (WITH NO DROP IN PRESSURE AT 76 PSIG) AND RAN A CAMERA INSIDE THEM TO ENSURE ALL SERVICE TEES WERE ACCOUNTED FOR AND TO LOOK FOR ANOMALIES. COLUMBIA TESTED APPROXIMATELY 448' OF HIGH DENSITY POLY ETHYLENE (HDPE) MAIN LINE AND 6 SERVICES ON THE NORTH SIDE OF THE STREET AND IT SUCCESSFULLY PASSED SEVERAL PRESSURE TESTS AT 76 PSIG (OPERATING PRESSURE), 15 INCHES WATER COLUMN AND 150 PSIG. IN ADDITION COLUMBIA TESTED APPROXIMATELY 1,175' OF HDPE MAIN LINE AND SERVICE ON THE STREET BEHIND INCIDENT SITE. AT 613 FLEMING FALLS RD., COLUMBIA PRESSURE TESTED THE SERVICE LINE AND CHECKED THE SERVICE REGULATOR FOR LOCK UP AND FLOW WITHOUT ISSUE AND NO LEAKAGE DETECTED. THE SERVICE LINE AT THE NEIGHBORING HOME (637 FLEMING FALLS RD) WAS ALSO TESTED AND FOUND TO BE LEAK FREE. COLUMBIA DID EXPLORATORY EXCAVATION AROUND THE AREA TO ENSURE CONDUITS DID NOT EXIST THAT COULD CONVEY MIGRATING GAS. COLUMBIA ALSO RAN A CAMERA IN THE SANITARY MAIN AND SEWER LATERALS TO ENSURE THAT A CROSS BORE DID NOT EXIST. UN-COLLAPSED STORM SEWERS WERE VIDEOED AS WELL TO ENSURE A CROSS BORE DID NOT EXIST. COLUMBIA WORKED WITH THE PUCO, STATE FIRE MARSHALL, A THIRD-PARTY CAUSE AND ORIGIN SPECIALIST, AND A GEOLOGIST TO DETERMINE A CAUSE. LABORATORY GAS ANALYSES AND OUR GEOLOGIST'S INTERPRETATION INDICATE THAT THE STRAY GAS SAMPLES HAD A COMPARABLE ISOTOPIC COMPOSITION AND MOLECULAR PROFILE, AND IS SIMILAR IN ORIGIN TO COLUMBIA'S PIPELINE GAS, HOWEVER, NATURALLY OCCURRING METHANE CONTAINING SIMILAR MOLECULAR AND ISOTOPIC PROFILE CANNOT BE COMPLETELY RULED OUT AS A POTENTIAL SOURCE. THE GEOLOGIST THEORIZES THAT GROUND WATER, IN COMBINATION WITH THE ABUNDANCE OF RAIN WATER, LIKELY CREATED CONDITIONS FAVORABLE FOR GAS MIGRATION TOWARD THE STRUCTURES AT 605 AND 613 FLEMING FALLS RD. COLUMBIA HAS DETERMINED THAT THE CAUSE OF THIS INCIDENT CANNOT BE FULLY ASCERTAINED. PLEASE CONSIDER THIS REPORT A FINAL REPORT. NOTE: UPDATED LATITUDE AND LONGITUDE 9-21-18