ENBRIDGE GAS OHIO

Incident Narrative

"A TRANSMISSION LINE LEAK WAS IDENTIFIED IN EGO'S GAS STORAGE SYSTEM (GROUP 8) AT APPROXIMATELY 16:15 EDT ON 10/18/2024 NEAR 9232 MUDBROOK ST NW IN JACKSON, OH AFTER A MEMBER OF THE PUBLIC CALLED IN AN ODOR COMPLAINT. LOCAL PERSONNEL UTILIZED VALVES TO SHUT IN THE LEAKING LINE AROUND 18:00 EDT THAT SAME DAY. AN ORIGINAL ASSESSMENT OF THE COSTS TO REPLACE THE LINE WERE UNDER THE $145,400 OPERATOR LOSS THRESHOLD FOR AN INCIDENT PER 191.3. ON 11/5/2024 AT APPROXIMATELY 9:20 EST, THE ENBRIDGE GAS OHIO PROJECT MANAGER FOR THE REPLACEMENT OF THE SECTION OF PIPE WITH THE LEAK INFORMED PIPELINE SAFETY THAT COSTS WERE NOW LIKELY TO EVENTUALLY EXCEED THE $145,400 THRESHOLD DUE TO HIGHER THAN EXPECTED ENVIRONMENTAL AND CONTRACTOR COSTS. THE LEAK WAS CALLED IN AS AN INCIDENT AT THAT TIME TO THE OHIO PUBLIC UTILITY COMMISSION AND THE NATIONAL RESPONSE CENTER. THE SECTION OF PIPE WITH THE LEAK HAS BEEN REMOVED AND SENT TO A 3RD PARTY FOR ANALYSIS. A NEW SECTION OF PIPE HAS BEEN INSTALLED TO REPLACE THE OLD LINE BUT IS NOT YET IN SERVICE. A SUPPLEMENTAL REPORT WILL BE PROVIDED WITH THE IN-SERVICE DATE AND RESULTS OF THE 3RD PARTY LAB ANALYSIS. 4/25/25 SUPPLEMENTAL UPDATE: LABORATORY ANALYSIS HAS BEEN COMPLETED. THE RESULTS OF THE METALLURGICAL ANALYSIS INDICATE THAT THE LEAK OCCURRED AT AN AREA OF DISCRETE PITTING FROM INTERNAL CORROSION AT THE BOTTOM OF THE PIPE (6:17 ORIENTATION). THE LEAK WAS LIKELY CAUSED BY THE PRESENCE OF AN ACIDIC BRINE (PH 2.92, MEASURED AT AMBIENT PRESSURE) WITH HIGH SALINITY. THE LOCALIZED CORROSION LIKELY OCCURRED AT BREAKS IN AN OTHERWISE THICK PROTECTIVE SCALE OR AT AREAS UNDER DEPOSITS AT THE BOTTOM OF THE PIPE. IT IS POSSIBLE THAT THERE WAS A GAS PHASE CONTRIBUTION (I.E., FROM CO2, H2S, AND/OR 02 CORROSION), HOWEVER, THE GAS PHASE CONTRIBUTION WAS LIKELY SECONDARY TO THE PRESENCE OF THE ACIDIC BRINE. THE CAUSE OF THE BRINE ACIDITY AT THIS LOCATION IS UNKNOWN, BUT A PH VALUE OF 2.92, MEASURED AT AMBIENT PRESSURE, IS IN EXCESS OF WHAT IS POSSIBLE FROM CO2 GAS DISSOLVED IN THE PROCESS STREAM. ENBRIDGE GAS OHIO HAS PLACED PERMANENT UT GAUGES ON THE LINE FOR FUTURE INTERNAL CORROSION MONITORING. PIPELINE WAS PLACED BACK INTO SERVICE ON 1/7/25. 5/12/2025 UPDATED FINAL REPORT: A14 WAS CHANGED TO ""ONSHORE PIPELINE"" TO REFLECT THAT PIPE WAS CONSIDERED A TRANSMISSION ASSET FOR REGULATORY PURPOSES. 5/20/2025: FINALIZING SUPPLEMENTAL REPORT WITH CHANGES TO A14. 1/12/2026: UPDATED FINAL REPORT: C1 WAS CHANGED FROM ""INTERSTATE"" TO ""INTRASTATE""."