CONSOLIDATED EDISON CO OF NEW YORK

Incident Narrative

ON WEDNESDAY, MARCH 20, 2013 LEAK SURVEY DETECTED 35% AT THE CURB LINE AND 25% IN A BAR-HOLE IN THE VICINITY OF A GAS TRANSMISSION MAIN TO THE GAS EMERGENCY RESPONSE CENTER (GERC). GAS DISTRIBUTION SYSTEM (GDS), GAS CONSTRUCTION AND SUPERVISION WERE NOTIFIED AND RESPONDED. GAS CONSTRUCTION CONDUCTED A LEAK INVESTIGATION SURVEY OVER THE ROUTE OF THE 1948 12"" STEEL TRANSMISSION MAIN (245 PSI SYSTEM) AND THE 16"" MEDIUM PRESSURE CAST IRON (MPCI) MAIN IN THE AREA. ALL SUBSURFACE STRUCTURES IN THE AREA WERE CHECKED AND FOUND CLEAR; THERE WERE NO BUILDINGS IN THE AREA. GAS CONTROL WAS NOTIFIED AND CONTINGENCY CASE 39-A WAS INITIATED. ISOLATION VALVES 25977 AND 25976 WERE STAFFED AND GAS CONTROL CONFIRMED COMMUNICATION WITH REMOTE OPERATED VALVE (ROV) 32717. GAS CREWS CONTINUED TO AERATE, PINPOINT AND MONITOR THE AREA. ON THURSDAY, MARCH 21, 2013 AT 08:41 THE INVESTIGATION IDENTIFIED A PROBABLE TRANSMISSION MAIN LEAK APPROXIMATELY 175' SOUTH OF THE TRANSCONTINENTAL GAS PIPELINE (TGPL) WHITE PLAINS GATE STATION LOCATED AT BRONX STREET AND MOTT STREET (WP).TRANSMISSION ENGINEERING, DISTRIBUTION ENGINEERING, GAS CONTROL, MAJOR PROJECTS, TECHNICAL OPERATIONS, GERC AND WESTCHESTER GAS OPERATIONS PARTICIPATED IN OPERATIONAL PLANNING TO IDENTIFY THE ACTIONS REQUIRED TO MAINTAIN SUPPLY TO THE DISTRIBUTION SYSTEM AS WELL AS THE ACTIONS REQUIRED TO REPAIR THE SUSPECTED 12"" COUPLING BELIEVED TO BE THE SOURCE OF THE LEAK. REPAIR PROCEDURE MPC-13-09 WAS INITIATED AND ON FRIDAY, MARCH 22, 2013 AT 10:16 THE SEGMENT OF TRANSMISSION MAIN WAS ISOLATED AND PRESSURE REDUCED FROM 214 PSI TO 62 PSI. REPAIR OPERATIONS CONTINUED AROUND-THE-CLOCK AND A VISIBLE LEAK WAS CONFIRMED ON A 12"" COMPRESSION COUPLING. A WELDED REPAIR SLEEVE WAS INSTALLED TO SECURE THE LEAK. A SECOND WELDED REPAIR SLEEVE WAS INSTALLED ON A COUPLING NOT LEAKING BUT IN CLOSE PROXIMITY AS A PRECAUTION. ON SATURDAY, MARCH 23, 2013 A PRELIMINARY MOBILE LEAK SURVEY WAS PERFORMED IN ADVANCE OF PRESSURE RESTORATION AND (2) LEAKS WERE FOUND ALONG THE ROUTE OF THE TRANSMISSION MAIN. THE LEAKS WERE INVESTIGATED AND IT WAS DETERMINED THE TRANSMISSION MAIN WAS NOT THE SOURCE OF THE READINGS DETECTED. A THIRD T-1 WAS DETECTED DURING PRESSURE RESTORATION AND A 16"" MPCI HUB WAS FOUND TO BE THE SOURCE OF THAT LEAK. ON MONDAY, MARCH 25, 2013 AT 02:00 THE ISOLATED SEGMENT WAS RETURNED TO NORMAL OPERATING PRESSURE. GAS CONTROL AND PRESSURE CONTROL ARE RETURNING THE REGULATOR STATIONS INVOLVED IN THIS PROCEDURE TO NORMAL SETTINGS. THERE WERE NO OUTAGES AS A RESULT OF THIS OPERATIONAL PLAN. NO EVACUATIONS, INJURIES OR MEDIA ATTENTION WERE REPORTED AS A RESULT OF THIS EVENT. THE WHITE PLAINS FIRE DEPARTMENT (WPFD) WAS NOTIFIED AND THE WPFD RESPONDED PER THE TRANSMISSION LEAK NOTIFICATION PROTOCOL AND REPAIR OPERATIONS WERE REVIEWED. THE US DOT AND NYS PSC WERE NOTIFIED AND THE PSC RESPONDED TO LOCATION. THIS WAS A SERIOUS LEVEL INCIDENT.