CENTRAL HUDSON GAS & ELECTRIC CORP

Incident Narrative

ON TUESDAY SEPTEMBER 3, 2024, TWO CENTRAL HUDSON GAS MECHANICS WERE PERFORMING A MONTHLY REGULATOR STATION INSPECTION AT THE HOPEWELL GAS REGULATOR STATION NEAR 6 CREST CT. HOPEWELL JUNCTION NY. THE REGULATOR STATION IS CONSTRUCTED WITH TWO REGULATOR RUNS IN PARALLEL WITH ONE RELIEF VALVE SERVING AS THE OVERPRESSURE PROTECTION DEVICE. THE REGULATOR STATION REDUCES PRESSURE FROM THE MP TRANSMISSION PIPELINE (MAOP 750 PSIG) TO 120 PSIG TO SERVE THE HH GAS DISTRIBUTION SYSTEM. THE TRANSMISSION PIPELINE WAS OPERATING AT APPROXIMATELY 425 PSIG AND THE DISTRIBUTION SYSTEM AT APPROXIMATELY 114 PSIG AT THE TIME OF THE INCIDENT. THE REGULATOR STATION IS LOCATED IN CLOSE PROXIMITY TO OVERHEAD TRANSMISSION ELECTRIC LINES. DURING THE MONTHLY INSPECTION, A LEAK ON A FITTING AT THE VORTEX HEATER WAS DISCOVERED. THE GAS MECHANIC DECIDED TO ISOLATE THE VORTEX HEATER TO MAKE THE NECESSARY REPAIRS. DURING THE ATTEMPT TO ISOLATE THE HEATER, THE GAS MECHANIC CLOSED A SERIES OF VALVES ON THE PILOT SUPPLY LINE OF THE REGULATOR WHICH CAUSED THE REGULATOR TO GO WIDE OPEN. AS A RESULT, THE PRESSURE DOWNSTREAM OF THE REGULATOR INCREASED AND EXCEEDED THE SET PRESSURE OF THE RELIEF VALVE. THE RELIEF VALVE OPERATED AND BEGAN TO VENT NATURAL GAS TO ATMOSPHERE. SHORTLY AFTER THE GAS STARTED VENTING, THE RELEASED GAS FROM RELIEF VALVE STACK IGNITED. THE INTENSITY OF THE PRESSURE AND HEAT FROM THE FLAME POSED AN IMMEDIATE DANGER TO BOTH GAS MECHANICS ON SITE. THE EMPLOYEES WERE ABLE TO SAFELY EXIT THE STATION AND ALERT SURROUNDING RESIDENCES AND EMERGENCY SERVICES, AND EVACUATE PEOPLE FROM THEIR HOMES. ONE GAS MECHANIC WENT TO THE HOSPITAL FOR EVALUATION AS A PRECAUTION. THE NUMBER OF EVACUATIONS PROVIDED IN THIS REPORT IS ESTIMATED AND IS BASED ON THE NUMBER OF BUILDINGS ON CREST CT. SHORTLY AFTER THE NATURAL GAS IGNITION, THE OVERHEAD ELECTRIC BURNT AND FELL TO THE GROUND ADJACENT TO THE REGULATOR STATION. THE ELECTRIC DEPARTMENT WAS CONTACTED AND RESPONDED TO REMEDIATE THE HAZARD. TO EXTINGUISH THE FIRE, THE REGULATOR STATION WAS ISOLATED FROM ALL SOURCES OF GAS BY CLOSING TRANSMISSION LINE VALVES ON THE MP PIPELINE AND CLOSING A DISTRIBUTION LINE VALVE ON THE HH LINE. THE FIRE EXTINGUISHED ITSELF ONCE THE GAS SUPPLY RAN OUT. NATURAL GAS CUSTOMERS SERVED FROM THE HH PIPELINE WERE NOT INTERRUPTED AS THIS PIPELINE IS SERVED BY ADDITIONAL NATURAL GAS REGULATOR STATIONS. THE 491 CUSTOMERS THAT WERE INTERRUPTED WERE FED FROM DIFFERENT REGULATOR STATIONS FED FROM THE MP LINE WITHIN THE ISOLATION ZONE THAT WAS BLOWN DOWN. THE MAJORITY WERE RESTORED THE NEXT DAY.