COLUMBIA GAS TRANSMISSION, LLC

Incident Narrative

PIPELINE 1656 IS A TRANSMISSION PIPELINE THAT IS OPERATED AND MAINTAINED BY COLUMBIA GAS TRANSMISSION, LLC (COLUMBIA) WITH AN OPERATOR ID 2616. COLUMBIA HAS IDENTIFIED A LEAK ON PIPELINE 1656 UNDER A TOWNSHIP ROADWAY NEAR THE TOWN OF GREENCASTLE, FRANKLIN COUNTY, PENNSYLVANIA. PIPELINE 1656 IS A 6-INCH DIAMETER, CARBON STEEL, 0.28-INCH WALL THICKNESS, BARE STEEL PIPELINE, WHICH IS CATHODICALLY PROTECTED IN THE AREA OF THE REPORTED LEAK. LINE 1656 HAS A MAXIMUM ALLOWABLE OPERATING PRESSURE OF 175 PSIG AND ITS OPERATING PRESSURE AT THE TIME OF DISCOVERY WAS APPROXIMATELY 165 PSIG. WHILE PERFORMING SCHEDULED CATHODIC PROTECTION SURVEYS, COLUMBIA OPERATIONS DISCOVERED THE PRESENCE OF NATURAL GAS IN A TEST STATION NEAR THE 100 BLOCK OF PENNSINGER ROAD, GREENCASTLE, PA. GAS MIGRATION STUDIES WERE PERFORMED, AND THE LOCAL DISTRIBUTION COMPANY PERFORMED GAS DETECTION SURVEYS WITHIN THE TWO NEARBY HOMES. NO NATURAL GAS WAS FOUND IN OR AT THE FOUNDATIONS OF EITHER HOME. THE LINE PRESSURE WAS REDUCED TO 100 PSIG TO MAINTAIN LOCAL MARKET. BELL HOLES WERE OPENED ON EITHER SIDE OF PENNSINGER ROAD, AND GAS MIGRATION SURVEYS HAVE BEEN PERFORMED TWICE DAILY SINCE DISCOVERY. AS OF JULY 7, 2022, PIPELINE 1656 HAS BEEN BLOW DOWN TO 0 PSIG AND 19 LDC CUSTOMERS HAVE BEEN PLACED ON TEMPORARY BOTTLED COMPRESSED NATURAL GAS (CNG) SERVICE. IN ADDITION, A CNG TANKER HAS BEEN PLACED TO KEEP THE TOWN OF HAGERSTOWN, MD IN SERVICE AS NEEDED. CURRENTLY HAGERSTOWN IS BEING SUPPLIED BY AN ALTERNATIVE SUPPLY. WORK WAS COMPLETED TO REPLACE 232 FEET OF FBE COATED CARBON STEEL PIPE ON JULY 18, 2022. THE PIPELINE HAS BEEN PURGED AND PLACED BACK INTO SERVICE AT 4:49PM EASTERN TIME ON JULY 18, 2022. THE INCIDENT INVESTIGATION REPORT WAS FINALIZED ON JANUARY 17, 2023. THE CAUSAL AND ROOT CAUSE FACTORS OF THIS PROCESS EQUIPMENT FAILURE INDICATE GENERAL EXTERNAL CORROSION LED TO A THROUGH WALL ANOMALY RESULTING IN THE RELEASE OF NATURAL GAS. THE CORROSION CAN LIKELY BE ATTRIBUTED TO INSUFFICIENT CATHODIC PROTECTION AT THE LEAK LOCATION OVER THE LIFE SPAN OF THE PIPE. FOR APPROXIMATELY THE FIRST 20 YEARS OF SERVICE THIS SECTION OF BARE STEEL PIPE OPERATED WITH NO CATHODIC PROTECTION IN PLACE.