DOMINION ENERGY OHIO

Incident Narrative

ON 8-3-21, AT APPROX. 1:00 PM, AN EXPLOSION AND FIRE OCCURRED AT A RESIDENTIAL PROPERTY AT 3645 E.57TH ST, CLEVELAND, OHIO. TWO ADULT INDIVIDUALS WERE INSIDE THE STRUCTURE AT THE TIME OF THE INCIDENT AND SUBSEQUENTLY HOSPITALIZED. THE INCIDENT SEVERELY DAMAGED THE STRUCTURE AT 3645 E.57TH ST, WHICH WAS RAZED ON THE EVENING OF 8-3-21 BY CITY OF CLEVELAND CONTRACTORS. TWO NEIGHBORING STRUCTURES (3643 AND 3649 E.57TH ST) ALSO SUSTAINED DAMAGES. ON 8-3-21, AT APPROX. 2:00 PM, DOMINION ENERGY OHIO (DEO) RECEIVED A CALL FROM THE CITY OF CLEVELAND FIRE DEPARTMENT REPORTING THE INCIDENT. DEO FIRST RESPONDER ARRIVED AT APPROX. 2:12 PM AND STOPPED THE FLOW OF GAS TO 3645 E.57TH BY CLOSING THE SERVICE LINE CURB VALVE AT APPROX. 2:35 PM. DEO ALSO SHUT OFF THE FLOW OF GAS TO NEIGHBORING STRUCTURES (3643 AND 3649 E.57TH) BY CLOSING THE SERVICE LINE CURB VALVES. DEO BAR-HOLED ALONG THE MAINS ON BOTH SIDES OF E.57TH AND ALONG THE CUSTOMER SERVICE LINES AT 3633, 3639, 3642, 3643, 3644, 3645, 3646, 3649, 3653, AND 3659 E.57TH, AND 0% READINGS WERE FOUND. DEO LEAK SURVEYED ALONG E.57TH AS WELL AS E.54TH, E.55TH, AND E.59TH. NO LEAKS WERE DETECTED, WITH THE EXCEPTION OF A GRADE-TWO LEAK AT 3683 E.55TH. DEO PERFORMED ODORANT TESTING AT 3653 E.57TH, AND THE ODORANT WAS READILY DETECTIBLE AT 0.48%. ON 8-3-21, THE GAS METER, MANIFOLD, AND A SECTION OF SERVICE LINE PIPING WERE REMOVED FROM THE BASEMENT AT 3645 E.57TH. DEO PRESSURE TESTED THE REMAINING SERVICE LINE PIPING AT 3645 E.57TH AT 7 OZ (OPERATING PRESSURE) FOR 10 MIN. A PRESSURE DROP OF APPROX. 0.5 OZ WAS OBSERVED, BUT NO LEAKS WERE DISCOVERED. A SECTION CONTAINING THE CURB VALVE AND MAIN-TO-CURB TRANSITION WAS REMOVED, AND THE REMAINING SERVICE LINE WAS RE-TESTED AT 7 OZ FOR 10 MIN. A PRESSURE DROP OF APPROX. 0.5 OZ WAS OBSERVED. CITY CONTRACTORS RAZED THE STRUCTURE AT 3645 E.57TH THAT EVENING. ON 8-4-21, DEO EXCAVATED, EXPOSED, AND RE-TESTED THE REMAINING SERVICE LINE (APPROX. 24 FT) AT 7 OZ FOR 10 MIN. A PRESSURE DROP OF APPROX. 1 OZ WAS OBSERVED, BUT NO IDENTIFIABLE LEAKS WERE DISCOVERED. A CUT WAS MADE APPROX. 8 FT FROM THE END OF THE SERVICE LINE (CLOSEST TO THE MAIN), AND THE 8-FT SECTION WAS RE-TESTED AT 7 OZ FOR 10 MIN. A PRESSURE DROP OF SLIGHTLY LESS THAN 2 OZ WAS OBSERVED, BUT NO IDENTIFIABLE LEAKS WERE DISCOVERED. THE REMAINING 16-FT SECTION WAS RE-TESTED AT 7 OZ FOR 10 MIN, AND NO PRESSURE DROP WAS OBSERVED. THE GAS METER, MANIFOLD, AND SERVICE LINE SECTIONS WERE PRESERVED FOR LABORATORY INSPECTION AND TESTING. THREE APPLIANCES (FURNACE, WATER HEATER, AND STOVE/RANGE) AND MISCELLANEOUS HOUSE LINE PIPING ALSO WERE IDENTIFIED DURING THE CITY'S POST-DEMOLITION DEBRIS REMOVAL ON 8-5-21 AND 8-6-21. THESE ARTIFACTS WERE EXAMINED ON 9-17-21. THE 8-FT SECTION OF SERVICE LINE THAT PREVIOUSLY WAS TESTED ON 8-4-21 WAS FLOW RATE LEAK TESTED AT 7 OZ, AND NO MEASURABLE FLOW RATE WAS OBSERVED. THE SERVICE LINE SECTION FROM THE BASEMENT OF 3645 E.57TH WAS KINKED APPROX. 45 DEGREES BY THE CITY'S CONTRACTORS DURING ITS REMOVAL ON 8-3-21, AND A THROUGH-WALL CRACK WAS OBSERVED AT THE KINK. THE KINKED SERVICE LINE SECTION WAS EXAMINED ON 12-17-21, WHICH INCLUDED COMPUTED TOMOGRAPHY (CT) SCANNING. EVIDENCE OF EXTERNAL CORROSION AND THINNING OF THE PIPING WALL WAS OBSERVED IN THE AREA WHERE THE SERVICE LINE PASSED THROUGH THE FOUNDATION INTO THE BASEMENT, WHICH WOULD HAVE CAUSED IT TO BE LESS RESISTANT TO BENDING FORCES. THE CRACK AT THE KINK WAS VISUALLY EXAMINED, REVEALING THAT THE PIPING WALL WAS COLLAPSED INTO THE INTERIOR OF THE SERVICE LINE. FOR REPORTING PURPOSES, DEO CLASSIFIES THE APPARENT CAUSE OF THIS INCIDENT AS EXTERNAL CORROSION FAILURE (SEE PART G1), BUT THE ROOT CAUSE REMAINS UNKNOWN AND UNDETERMINED. A NATURAL GAS LEAK FROM EXTERNAL CORROSION ON THE SERVICE LINE INSIDE THE BASEMENT CANNOT BE RULED OUT AS A POSSIBLE FUEL SOURCE, BUT THE PHYSICAL EVIDENCE WAS COMPROMISED DURING POST-INCIDENT REMOVAL BY THE CITY'S CONTRACTORS.