"MONROE GAS STORAGE COMPANY, LLC"

Incident Narrative

"ON FRIDAY AFTERNOON 9/20/24 AT 13:21 CT, A TECHNICIAN AT THE MONROE GAS STORAGE COMPRESSOR STATION OBSERVED SMALL BUBBLES RISING WITHIN A PUDDLE OF WATER WHILE DOING REGULAR INSPECTION ROUNDS WITHIN THE FENCED FACILITY. AFTER CONFIRMING THE PRESENCE OF NATURAL GAS AT THE LOCATION AND SUSPECTING A PINHOLE LEAK, THE 18"" EASTSIDE GAS TRANSMISSION LINE WAS ISOLATED BY MANUALLY CLOSING THE DOWNSTREAM VALVES. BECAUSE THE LINE WAS NOT FLOWING AT THE TIME, THE UPSTREAM VALVES WERE ALREADY CLOSED. THE EFFECTED LINE SEGMENT WAS ISOLATED BY 14:13 CT. AFTER INITIAL COORDINATION REGARDING POSSIBLE COST OF REPAIR, IT WAS DETERMINED TO CLASSIFY THE EVENT AS AN INCIDENT AND NOTIFY THE NATIONAL RESPONSE CENTER (NRC). THE NRC WAS NOTIFIED BY THE WILLIAMS SECURITY OPERATIONS CENTER AT 15:27 CT. THE PIPELINE WAS SAFELY BLOWN DOWN WITH LOCK OUT / TAG OUT COMPLETED BY 19:20 CT THAT EVENING. DUE TO THE PIPELINE'S 10' DEPTH IN THE AREA, IT TOOK MULTIPLE DAYS FOR CONTRACTORS TO CLEAN THE LINE THROUGH CLEANING PIGS, PURGE WITH NITROGEN AND POTHOLE THROUGH HYDROVACING TO PINPOINT THE LEAK LOCATION. ONCE IDENTIFIED (THROUGH DETECTING THE PRESENCE OF NITROGEN), THE LEAK LOCATION WAS FULLY AND SAFELY EXCAVATED (CONSIDERING THE SIGNIFICANT DEPTH) ON 10/14/24. AS OF 10/15/24, INTERNAL CORROSION WAS FOUND AT THE PINHOLE LEAK LOCATION. THE EFFECTED PIPE IMMEDIATELY NEAR THE LEAK LOCATION WAS CUT-OUT ON 10/17/24 AND SENT TO A LAB FOR ANALYSIS. WILLIAMS OPERATIONS, PIPELINE INTEGRITY AND CONSTRUCTION TEAMS ESTABLISHED A CONSERVATIVE PLAN TO REPLACE NECESSARY PIPE AND RETURN THE LINE TO SERVICE. APPROXIMATELY 350 FEET OF 18-INCH PIPE IN THE LOW AREA OF THE PIPELINE (WITHIN THE FACILITY) WAS REPLACED AND HYDROTESTED. THE LINE WAS RETURNED TO SERVICE ON 11/9/2024. THE CAUSE IS SUSPECTED TO BE SULFATE REDUCING BACTERIA MICROBIOLOGICALLY INFLUENCED CORROSION (SRB-MIC) BASED ON LAB RESULTS. REPRESENTATIVES FROM OPERATIONS, MANAGEMENT AND PIPELINE INTEGRITY HAVE ESTABLISHED AN INTERNAL CORROSION MITIGATION PLAN TO PREVENT REOCCURRENCE. COUPONS HAVE BEEN INSTALLED AT EACH WELL HEAD LOCATION AND OTHER LOCATIONS, BASED ON INTERNAL CORROSION DATA GATHERED, OPERATIONS, MANAGEMENT, COMPLIANCE AND CORROSION DEPARTMENT WILL DEEM IF MORE LOCATIONS ARE NEEDED. A PIGGING PROGRAM THAT INCLUDES ALL 13 LATERALS IS FORTHCOMING, WITH ADDITIONAL FOCUS ON THE 18"" LATERAL."