CONSOLIDATED EDISON CO OF NEW YORK

Incident Narrative

ON APRIL 18, 2011 A WESTCHESTER GAS DISTRIBUTION SERVICES (GDS) MECHANIC PERFORMED A TRANSMISSION DRIP INSPECTION SURVEY AND DETECTED 35% GAS-IN-AIR READING IN THE REGULATOR MANHOLE OF STATION GR-498 LOCATED AT LINCOLN AVENUE AND BROOKSIDE WAY, HARRISON. THE GAS EMERGENCY RESPONSE CENTER (GERC) DISPACTHED GAS CONSTRUCTION CREWS AND SUPERVISORS TO THE LOCATION. THE LEAK WAS INVESTIGATED AND A 1"" LUBRICATING VALVE ON A DRIP RISER WAS DETERMINED TO BE THE SOURCE OF THE LEAK. THE VALVE WAS SERVICED AND THE LEAK SECURED. THE AREA OF WORK WAS LEFT PLATED AND SECURED OVERNIGHT. ON APRIL 19, 2011, THE LOCATION WAS SURVEILLED DURING AN INSPECTION OF THE PIPING AND A LEAK CONDITION WAS FOUND. AN OPERATIONAL PLAN WHICH WAS PREVIOUSLY DEVELOPED WAS IMPLEMENTED AFTER A LEAK ON A 1"" DRIP RISER COMPRESSION COUPLING AT THE INLET OF THIS REGULATOR STATION WAS DETECTED. THE PLAN CALLED FOR ISOLATION OF THE FIRST STAGE OF GR-498 (212 PSI INLET) WHICH SUPPLIES A 60 PSI HIGH PRESSURE DISTRIBUTION SYSTEM. THE EFFECTED SECTION OF TRANSMISSION PRESSURE PIPE WAS ISOLATED, DEPRESSURIZED AND THE LEAK CONDITION ELIMINATED. THERE WAS NO REDUCTION IN PRESSURE OF THE HIGH PRESSURE SYSTEM, OR LOSS OF CUSTOMERS, AS A RESULT OF THESE ACTIONS. GAS CONSTRUCTION, GDS, PRESSURE CONTROL AND TRANSMISSION ENGINEERING REMAINED ON LOCATION UNTIL WORK WAS COMPLETED FOR THE REMOVAL OF THE STANDPIPE AND COUPLING AND THE INSTALLATION OF A WELDED HIGH-HAT. GR-498-L1 WAS PLACED BACK IN NORMAL SERVICE UPON COMPLETION OF ALL WORK AT 23:49 HRS ON APRIL 19, 2011. THE US DOT AND NYS PSC WERE NOTIFIED. THIS IS A SERIOUS LEVEL EVENT. NOTE--THIS GAS DISTRIBUTION INCIDENT REPORT IS GENERATED TO REPLACE RESCINDED GAS TRANSMISSION INCIDENT REPORT 20110048-15869