CONSOLIDATED EDISON CO OF NEW YORK

Incident Narrative

ON NOVEMBER 14, 2012 AT 13:12 HRS. GAS CONSTRUCTION REPORTED A POSSIBLE LEAK ON THE 24"" STEEL TRANSMISSION MAIN AT 23 MAPLE STREET, EASTCHESTER, NY TO THE GAS EMERGENCY RESPONSE CENTER (GERC). TWO REPAIRS WERE PREVIOUSLY MADE ON A PARALLEL 4"" HIGH PRESSURE 1932 STEEL DISTRIBUTION MAIN AND THE GAS READINGS INDICATED A POSSIBLE LEAK ON THE TRANSMISSION MAIN. A CODE MURRE (MULTIPLE RESOURCE RESPONSE EVENT) WAS INITIATED AND THE GERC DISPATCHED GAS DISTRIBUTION SERVICES (GDS), THE EMERGENCY RESPONSE GROUP (ERG) AND SUPERVISION.GAS ENGINEERING, PRESSURE CONTROL AND GAS CONTROL WERE NOTIFIED. GERC AND GAS CONTROL IDENTIFIED ROV 25934 AND MV 25968 TO ISOLATE THE AREA PER CONTINGENCY CASE 34A. GAS CONTROL CONFIRMED COMMUNICATION WITH ROV 25934 AND GDS INSPECTED AND CONFIRMED ACCESSIBILITY AND POSITION OF MV 27235 (OPEN) AND MV # 36697 (CLOSED). THESE VALVES ARE STRADDLE CONNECTIONS TO REGULATOR STATION GR-425 (TRANSMISSION-HIGH PRESSURE) AND WERE NEEDED FOR MAIN DEPRESSURIZATION AND ISOLATION AS REQUIRED. THE LEAK WAS STAFFED OVERNIGHT AND AN OPERATIONAL PLAN WAS DEVELOPED. AT 09:53 ON NOVEMBER 15, 2012 THE ISOLATION OF THIS SEGMENT OF TRANSMISSION MAIN WAS CONFIRMED. PRESSURE CONTROL WAS ON LOCATION AND THE SEGMENT WAS DEPRESSURIZED VIA GR-425 AND EXCAVATION COMMENCED TO EXPOSE THE SOURCE OF THE LEAK. GAS CONTROL DECLARED A CONDITION YELLOW AND ISSUED A LIMITED WORK ORDER ON THE 245 PSI TRANSMISSION SYSTEM TO ENSURE SYSTEM SUPPLY. CORROSION CONTROL PERFORMED A PATROL OVER THIS SYSTEM TO ENSURE NO UNREGISTERED ACTIVITY IS ONGOING THAT WOULD JEOPARDIZE THE GAS TRANSMISSION SYSTEM. AROUND-THE-CLOCK OPERATIONS CONTINUED AND ON FRIDAY, NOVEMBER 15, 2012 AT 19:15 HRS A CONFIRMED VISUAL LEAK ON A 24"" COUPLING APPROXIMATELY 20' SOUTH OF THE SERVICE SUPPLYING # 20 MAPLE ST (TE). A WELDED REPAIR SLEEVE WAS INSTALLED, AND THE ASSOCIATED TESTING WAS SUCCESSFUL. THE AFFECTED SEGMENT OF MAIN WAS RE-ENERGIZED AND DURING THE INCREMENTAL PRESSURE INCREASE AND ASSOCIATED LEAK SURVEILLANCE, A SECOND LEAK WAS DETECTED OVER A COUPLING APPROXIMATELY 40' SOUTH OF THE ORIGINAL REPAIR. THE MAIN WAS DEPRESSURIZED AND A WELDED REPAIR SLEEVE WAS SUCCESSFULLY INSTALLED AND TESTED. THE MAIN WAS RE-ENERGIZED AND NO OTHER LEAKS FOUND. BRONX CONSTRUCTION-CAPITAL, WESTCHESTER GAS OPERATIONS, PRESSURE CONTROL AND TRANSMISSION ENGINEERING-MAJOR PROJECTS WERE ON LOCATION. THE TRANSMISSION SYSTEM WAS RETURNED TO NORMAL OPERATING CONDITIONS ON SUNDAY NOVEMBER 18, 2012 AT 11:12 HRS. THE US DOT, NYS PSC AND TEFD WERE NOTIFIED. THE TEFD AND PSC VISITED THE LOCATION AND WERE KEPT APPRISED. MEDIA RELATIONS WAS UPDATED DUE TO AN INQUIRY FROM BLOOMBERG NEWS. THERE WERE NO EVACUATIONS OR INJURIES ATTRIBUTED TO THIS INCIDENT.THIS WAS A SERIOUS LEVEL INCIDENT.