COLUMBIA GAS TRANSMISSION, LLC

Incident Narrative

ON SEPTEMBER 26TH, 2018 AT 08:21, COLUMBIA GAS TRANSMISSION, LLC (COLUMBIA) REPORTED AN UNINTENDED RELEASE OF NATURAL GAS TO THE NATIONAL REPORTING CENTER (NRC). THIS INCIDENT WAS THE RESULT OF LAND MOVEMENT (SLIP) OCCURRING ALONG THE RIGHT-OF-WAY, DUE TO SEVERAL DAYS OF HEAVY RAINS. THE ABOVE GROUND PIPELINE NUMBER 8012 SUFFERED BUCKLING DUE TO THE FORCE OF THE LAND MOVEMENT. FRACTURES RESULTED IN THESE BUCKLED AREAS WHICH WAS THE CAUSE OF THE UNINTENDED RELEASE OF NATURAL GAS. NO RUPTURE OR DISCONTINUITY OF THE PIPE OCCURRED. COLUMBIA GAS TRANSMISSION, LLC. OPERATOR ID 2616 OPERATES AND MAINTAINS LINE 8012. THE PIPELINE MATERIAL IS BARE STEEL WITH 8.625-INCH DIAMETER AND 0.277-INCH WALL THICKNESS. THIS PIPELINE HAS A MAXIMUM ALLOWABLE OPERATING PRESSURE OF 70 PSIG. UPON RESPONSE TO THE INCIDENT SITE, COLUMBIA OPERATIONS PERSONNEL SECURED THE SITE AND MADE IT SAFE TO THE PUBLIC. THE NATURAL GAS LEAK OCCURRED APPROXIMATELY 30 FEET FROM A RAILWAY. THE RAILROAD OPERATOR WAS CONTACTED BY COLUMBIA. THIS PIPELINE IS A SINGLE-FEED PIPELINE TO THE TOWN OF WESTERNPORT, MARYLAND. THE TOWN IS SERVED BY A LOCAL DISTRIBUTION COMPANY (LDC) AND HAD 800 TO 1,200 NATURAL GAS CUSTOMERS AT THE TIME OF THE INCIDENT. THE LDC GAVE COLUMBIA THE APPROVAL TO REDUCE THE PRESSURE TO 25 PSIG UNTIL THE REPAIRS COULD BE MADE. TEMPORARY PLASTIC PIPELINE WAS LAID ON TOP OF THE GROUND TO PROVIDE SERVICE TO THE TOWN OF WESTERNPORT, MD. A GEOTECHNICAL ENGINEERING FIRM WAS CONTRACTED TO DEVELOP A SITE REMEDIATION PLAN. THIS PLAN CONSISTED OF THE FOLLOWING COMPONENTS; TRENCH DRAINS TO DEWATER THE SITE, SOIL STABILIZATION, SLOPE BREAKERS, DIVERSION BERMS WITH A DISCHARGE TRENCH DRAIN AT THE TOE OF THE SLOPE. THESE MEASURES WERE PUT INTO PLACE TO REDUCE FUTURE REOCCURRENCE. THIS SLOPE MANAGEMENT PLAN WAS PERFORMED CONCURRENTLY WITH THE INSTALLATION OF APPROXIMATELY 924 FEET OF 8-INCH PLASTIC PIPELINE (SDR 11 PE 3408). IN TWO ADDITIONAL PHASES OF THIS PROJECT, THE ADJOINING RAIL ROAD AND NORTH BRANCH POTOMAC RIVER CROSSINGS WERE REPLACED, AND TWO METER LOCATIONS WERE RELOCATED. AN INITIAL NRC REPORT WAS FILED WITH THE NRC 1225754 ON SEPTEMBER 26, 2018 AND A 48-HOUR UPDATE WAS PROVIDED NRC 1225907 ON SEPTEMBER 27, 2018.