SUMMIT MIDSTREAM PARTNERS, LLC

Incident Narrative

ON MARCH 20, 2021 A LEAK WAS DISCOVERED BY OPERATIONS PERSONNEL AT SUMMIT'S DIVIDE STATION. THE LEAK OCCURRED DUE TO A CRACK IN THE FLANGE ON A 12"" VALVE THAT IS ATTACHED TO A 55,000 BBL TANK (TANK 1904). THE VALVE IS PART OF THE LINE UTILIZED FOR THE TRUCK UNLOADING SKID WITHIN THE STATION. APPROXIMATELY 525 BBLS OF CRUDE OIL WERE RELEASED BEFORE THE VALVE COULD BE ISOLATED. THE PRODUCT WAS CONFINED WITHIN SECONDARY CONTAINMENT AND DID NOT LEAVE SUMMIT'S PROPERTY OR IMPACT ANY BODY OF WATER. APPROXIMATELY 400 BBLS WERE RECOVERED. THE IMPACTED SOIL WAS REMEDIATED AND SENT TO A DISPOSAL FACILITY. SUMMIT IS STILL AWAITING FINAL SOIL SAMPLE RESULTS. THE VALVE WAS REPLACED WITH A LIKE-IN-KIND VALVE. THE FAILED VALVE WAS SENT FOR FAILURE ANALYSIS AND THE RESULTS ARE STILL PENDING. FINAL COST RELATED TO EMERGENCY RESPONSE, REMEDIATION, CLEAN-UP AND FINAL REPAIR HAVE NOT BEEN FINALIZED. A SUPPLEMENTAL REPORT WILL BE SUBMITTED TO REPORT FINAL COST AND FAILURE ANALYSIS RESULTS. DIVIDE STATION IS BACK TO NORMAL OPERATION BUT TANK 1904 REMAINS ISOLATED AND HAS NOT RETURNED TO SERVICE. ON 5/21/21, A SUPPLEMENTAL REPORT WAS SUBMITTED TO UPDATE THE ESTIMATED COSTS ASSOCIATED WITH THE ACCIDENT. FAILURE ANALYSIS IS STILL ONGOING. AN ADDITIONAL SUPPLEMENTAL/FINAL REPORT WILL BE SUBMITTED WHEN FAILURE ANALYSIS AND TOTAL COSTS ARE FINALIZED. A SUPPLEMENTAL/FINAL REPORT WAS SUBMITTED ON 7/30/21 TO CORRECT APPARENT CAUSE AND PROVIDE A NARRATIVE OF ACCIDENT INVESTIGATION FINDINGS . FAILURE ANALYSIS OF THE VALVE INDICATED NO METALLURGICAL ISSUES AND ANALYSIS OF LIQUID SAMPLES DID NOT SHOW A CORROSIVE PRODUCT, SO FURTHER INVESTIGATION WAS INITIATED. TWO CORROSION CONTROL SERVICE COMPANIES WERE CONTRACTED TO INDEPENDENTLY EVALUATE THE CP SYSTEMS AT DIVIDE STATION TO DETERMINE IF THE FAILURE WAS CORROSION RELATED. DIVIDE STATION HAS A 20,000 BBL BREAKOUT TANK, 55,000 BBL BREAKOUT TANK AND ASSOCIATED PUMPS AND STATION PIPING. EACH BREAKOUT TANK HAS AN INDEPENDENT CP SYSTEM CONSISTING OF TI RIBBON ANODES, REFERENCE CELLS AND A RECTIFIER TO PROTECT THE TANK BOTTOM. THE STATION PIPING IS PROTECTED BY A SEPARATE CP SYSTEM CONSISTING OF A DEEP ANODE GROUND BED AND RECTIFIER. THE FAILURE OCCURRED AT THE FLANGED CONNECTION OF THE 12"" VALVE AND A SHORT PIECE OF PIPING THAT IS ATTACHED TO THE TANK NOZZLE AT THE OTHER END. THIS FLANGED CONNECTION IS ALSO AN ELECTRICAL ISOLATION POINT BETWEEN THE TANK AND THE STATION CP SYSTEMS. THE PUP OF PIPING AND THE NOZZLE ARE INTERNALLY COATED. THE VALVE HAS NO INTERNAL COATING. THERE WAS A SLUDGE OF PRODUCT THAT HAD COLLECTED AT THE BOTTOM OF THE VALVE AND TANK PIPING CONNECTION THAT WAS COMPRISED OF AN OIL AND WATER MIXTURE. THE WATER COMPONENT TO THE PRODUCT ACTED AS A LOW RESISTIVITY ELECTROLYTE AND ALLOWED STRAY CURRENT TO BYPASS THE ISOLATION KIT THROUGH THE PRODUCT AND CAUSE INTERNAL CORROSION OF THE VALVE FLANGE AT THE FLANGED CONNECTION. BOTH THIRD PARTY CORROSION SERVICE COMPANIES REACHED THE SAME CONCLUSION THAT THE FAILURE WAS CAUSED BY WHAT WAS DEEMED INTERNAL CURRENT TRANSFER. CORRECTIVE ACTION WAS TAKEN TO INTEGRATE THE THREE SEPARATE CP SYSTEMS INTO ONE CP SYSTEM. LESSONS LEARNED AND CORRECTIVE ACTIONS WERE IMPLEMENTED AT SUMMIT'S OTHER FACILITY, EPPING STATION, IN THE POLAR DIVIDE SYSTEM WHERE A SIMILAR CP SYSTEM DESIGN WAS IN PLACE WITH A 20,000 BBL TANK, PUMPS AND STATION PIPING.