MID-CONTINENT FRACTIONATION AND STORAGE, L.L.C.

Incident Narrative

AT 7:35 PM ON 3/1/2018 THE PIPELINE CONTROLLER RECEIVED A SHUTDOWN ALARM FOR THE MITCHELL STATION NEAR THE METER RUNS. THE SHUTDOWN OCCURRED DUE TO HIGH HAZARDOUS GAS LEVELS. THE CONTROLLER SENT A TECHNICIAN TO THE MITCHELL FACILITY TO INVESTIGATE. THE CONTROLLER IMMEDIATELY BEGAN TO PAN A SECURITY CAMERA TO THE AREA TO SEARCH FOR THE HAZARDOUS GAS SOURCE. DUE TO THE CHARACTERISTICS OF THE ETHANE/PROPANE MIX AND WEATHER CONDITIONS, IT WAS DIFFICULT TO DETERMINE THE SOURCE OF THE LEAK. THE TECHNICIAN ARRIVED ON SCENE AND EVALUATED THE SITUATION AND NOTIFIED THE CONTROLLER THAT THE LEAK WAS LOCATED NEAR THE ENCLOSURE OF VF-11101 (COALESCING FILTER). BASED ON THE LEAK LOCATION INFORMATION, THE CONTROLLER FURTHER ISOLATED THE LEAK BY REMOTELY CLOSING ADJACENT VALVES. THE LEAK WAS FULLY STOPPED BY 10:30 PM AND THE SITE WAS RENDERED SAFE. A SECONDARY FILTER WAS USED TO PLACE THE FACILITY BACK IN SERVICE AT 11:30 PM. THE FILTER WAS BLOWN DOWN AND PURGED WITH NITROGEN. THE SOURCE OF THE LEAK WAS IDENTIFIED AS THE PRESSURE WARNING DEVICE O-RING. THE PRESSURE WARNING DEVICE WAS REMOVED AND THE DEFECTIVE O-RING WAS REPLACED. THE PRESSURE WARNING DEVICE WAS REINSTALLED BUT THE FILTER WAS LEFT OUT OF SERVICE UNTIL THE ROOT CAUSE ANALYSIS WAS PERFORMED. THE RCA CONFIRMED THAT THE O-RING WAS THE ONLY FAILED COMPONENT AND THAT NO OTHER HAZARDS EXISTED; AS A RESULT, THE FILTER WAS PLACED BACK IN SERVICE ON MONDAY (3/5/2018) AT 2:00 PM.