CONSUMERS ENERGY CO

Incident Narrative

ON DECEMBER 30, 2023, AT APPROXIMATELY 05:04 HOURS A CONSUMERS ENERGY WHITE PIGEON COMPRESSOR STATION EMPLOYEE RESIDING NEAR THE STATION REPORTED HEARING WHAT SEEMED TO BE VENTING GAS. THE WHITE PIGEON COMPRESSOR STATION IS IN WHITE PIGEON, MICHIGAN (ST. JOSEPH COUNTY). THE EMPLOYEE ARRIVED AT THE SITE AT APPROXIMATELY 05:15 HOURS AND DISCOVERED GAS VENTING FROM A BLOWDOWN VALVE (VALVE 623) AND PROMPTLY ACTIVATE THE PLANT 2 FIREGATE SYSTEM, CLOSING THE BLOCK VALVE AND SUCCESSFULLY STOPPED GAS FROM VENTING. AT THE TIME OF THE INCIDENT, PLANT 2 WAS AVAILABLE FOR SERVICE, BUT THE UNITS WERE OFFLINE AND THERE WAS NO GAS FLOW IN THE PIPE SEGMENT. IN RESPONSE TO THE INCIDENT THE PLANT WAS TAKEN OUT OF SERVICE FOR A THOROUGH EVALUATION. ON JANUARY 2, 2024, DURING FURTHER INVESTIGATION, IT WAS DETERMINED THE PNEUMATIC PRESSURE SWITCH'S PILOT VALVE DEDICATED TO VALVE 623, O-RING WAS DAMAGED, CAUSING THE BLOWDOWN VALVE 623 TO ACTUATE. BECAUSE OF THE INDIVIDUAL COMPONENT FAILURE, THERE WAS NO DECREASE IN THE OVERALL PLANT 2 PILOT SYSTEM PRESSURE. BECAUSE THERE WAS NO LOSS IN PILOT SYSTEM PRESSURE, THE FIREGATE SYSTEM DID NOT ACTIVATE WHICH ALLOWED GAS TO CONTINUOUSLY VENT UNTIL THE STATION MECHANIC MANUALLY INITIATED IT. SCADA INFORMATION WAS UTILIZED TO CONFIRM THE FAILURE. HOWEVER, THERE ARE NO ALARMS THAT WOULD BE RECEIVED BY CONSUMERS ENERGY GAS CONTROL TO INDICATE THIS SPECIFIC FAILURE HAD OCCURRED. THE ROOT CAUSE WAS DETERMINED TO BE INADEQUATE MAINTENANCE. OUR INSPECTION PLAN DID NOT INCLUDE DISASSEMBLING THE EQUIPMENT AND REPLACING THE SOFT GOODS (O-RING) EVERY TWO YEARS AS SUGGESTED BY THE MANUFACTURER. TO PREVENT REOCCURRENCE, THE SOFT GOODS OF THE PNEUMATIC SWITCH WERE REPLACED, AND THE SWITCH WAS REASSEMBLED AND TESTED. THREE OTHER PNEUMATIC SWITCHES WITHIN THE PLANT WERE ALSO DISASSEMBLED, INSPECTED AND THE SOFT GOODS REPLACED AND TESTED BEFORE RETURNING THE EQUIPMENT TO NORMAL OPERATIONS ON JANUARY 2, 2024, AT APPROXIMATELY 14:30 HOURS. ADDITIONALLY, MAINTENANCE PLANS WILL BE CREATED TO INSPECT FOR DAMAGE AND REPLACE THE SOFT GOOD AT A SPECIFIED FREQUENCY AS SUGGESTED BY THE MANUFACTURER.