CONSUMERS ENERGY CO

Incident Narrative

A FAILURE OCCURRED ON 6"" PLASTIC DISTRIBUTION GAS MAIN IN THE CITY OF GLADWIN, MICHIGAN, RESULTING IN A LEAK THAT REQUIRED EVACUATION OF SEVERAL SURROUNDING STRUCTURES. AS PART OF THE INCIDENT RESPONSE, A GAS SERVICE WORKER CHECKED THE HOME ACROSS THE STREET FROM THE FAILURE POINT, AND PERFORMED ADDITIONAL BAR TESTS WITHIN THE SOIL NEAR THE FAILURE. NONE OF THESE TESTS FOUND ANY GAS MIGRATION. ALL THE GAS WAS VENTING TO ATMOSPHERE DIRECTLY ABOVE THE POINT OF FAILURE. THE POINT OF FAILURE ON THE MAIN WAS UNDER A COUNTY DRAIN DITCH, APPROXIMATELY 20' BELOW THE ROAD GRADE AND UNDER 14' OF SOIL. THE MAIN WAS CAPPED ON EACH SIDE OF THE FAILURE UPON SHUTOFF. THE FAILURE POINT WAS LATER EXTRACTED AND ANALYZED, REVEALING A FAILED BUTT FUSE JOINT. INADEQUATE FUSE BEAD ROLLOVER WAS OBSERVED ON ONE SIDE OF THE FUSE, INDICATING POSSIBLE INCOMPLETE FACING PRIOR TO UTILIZING THE HYDRAULIC BUTT FUSE MACHINE. THE NON-FUSED ZONE WAS CHARACTERIZED BY A GENERALLY SMOOTH FLAT SURFACE APPEARANCE, AS WELL AS PARALLEL CUT MARKS WHICH LIKELY INDICATE THAT THE SURFACE HAD NOT BEEN HEATED TO THE MELTING POINT DURING THE JOINT FUSION OPERATION. INITIAL ESTIMATES INDICATED THAT MORE THAN 3 MMCF OF GAS MAY HAVE BEEN RELEASED DURING THE LEAK, BUT REVISED FINDINGS (BASED ON OBSERVATIONS OF THE FAILED FUSE; SEE ATTACHED), INDICATE A GAS RELEASE OF LESS THAN 1 MMCF. A SUPPLEMENTAL PHMSA INCIDENT REPORT IS BEING SUBMITTED HEREWITH TO REFLECT THIS, AND ALSO REFLECT THE COSTS INCURRED DURING REPLACEMENT AND INVESTIGATION OF THE FAILED MAIN.