COLONIAL PIPELINE CO

Incident Narrative

ON 7/4/2022 AT 10:30PM, THE ALPHARETTA CONTROL CENTER (ACC) WAS CONTACTED BY LOUDON COUNTY (TN 911) AS A RESULT OF RESPONDING TO A HOMEOWNER CALL OF GASOLINE ODOR COMING FROM THE SUGARLIMB TRAP SITE ON LINE 18. LOCAL COLONIAL PERSONNEL WAS DISPATCHED TO THE SITE FOR INVESTIGATION AT 10:35PM, AND THE ACC SHUTDOWN LINE 18 AT 10:45PM BY DOUBLE BLOCKING WEST (UPSTREAM) OF THE FACILITY, DEPRESSURIZING THE SUGARLIMB TRAP SITE, AND CLOSING OUT KNOXVILLE DELIVERY (DOWNSTREAM) ON NO FLOW. LOCAL COLONIAL PERSONNEL ARRIVED ONSITE AT 11:00PM AND CONFIRMED GASOLINE FLOWING FROM A 2 INCH VALVE ON LINE 18 DOWNSTREAM OF THE LAUNCHING TRAP. THE PERSONNEL EXITED THE FACILITY AND SECURED THE PERIMETER MAINTAINING A SAFE DISTANCE UNTIL APPROPRIATE RESOURCES ARRIVED. ADDITIONAL INTERNAL NOTIFICATION WERE MADE TO MOBILIZE RESOURCES TO ADDRESS DISCOVERED CONDITIONS. AT 11:54PM THE LOUDON COUNTY FIRE DEPARTMENT EVACUATED THE NEIGHBORING RESIDENCE OUT OF AN ABUNDANCE OF CAUTION. EXTERNAL NOTIFICATIONS WERE MADE TO TEMA AT 12:52AM. COLONIAL ISSUED AN INTERNAL EMERGENCY NOTIFICATION ON 7/5/2022 AT 08:53AM FOR AWARENESS AND TO MOBILIZE ADDITIONAL RESOURCES. AN INCIDENT COMMAND POST WAS ESTABLISHED TO SUPPORT THE RESPONSE. A DRAIN UP OF LINE 18 WAS COMPLETED ON 7/5/2022 AT 4:04PM REMOVING ALL REMAINING PRODUCT FROM THE ISOLATED SEGMENT OF PIPE. ONCE THE DRAIN UP WAS COMPLETE, THE 2 INCH VALVE WAS REMOVED FROM THE TOR FITTING AND THE FITTING WAS PLUGGED AND CAPPED. THE RELEASE WAS DUE TO THE FAILURE OF A BALL VALVE. THE SCREWS THAT HELD THE STEM ASSEMBLY TO THE VALVES FRACTURED. THE FAILURE OF THE SCREWS WAS THE RESULT OF GRADUAL MECHANICAL OVERLOAD. THIS IS SHOWN BY THE PRESENCE OF ARREST MARKS, MICROVOID DIMPLES, AND MIXED BRITTLE MORPHOLOGY ON THE FRACTURE SURFACES OF BOTH SCREWS. MECHANICAL OVERLOAD OCCURS WHEN THE APPLIED FORCES EXCEED THE STRENGTH OF THE MATERIAL, AND A FACTURE OCCURS. BOTH SCREWS HAD LIKELY PRESENCE OF A QUENCH CRACK. UPDATE: ON 3/8/2023 AN NRC NOTIFICATION WAS MADE WHEN IT WAS DISCOVERED THAT SURFACE WATER ANALYSIS ALONG HUBBARD BRANCH CREEK (SOUTH OF, AND DOWNGRADIENT OF THE RELEASE SITE) RESULTED IN CONCENTRATIONS ABOVE THE TENNESSEE DEPARTMENT OF ENVIRONMENT & CONSERVATION (TDEC) SURFACE WATER DOMESTIC SUPPLY SCREENING LEVEL. SINCE THE 3/8/2023 NRC NOTIFICATION, THERE HAVE BEEN ADDITIONAL EFFORTS TO FURTHER ASSESS GROUNDWATER AND INCREASED SAMPLING FREQUENCY OF THE SURFACE WATERS. THE MOST RECENT SAMPLE RESULTS FROM 3/22/2023 DEMONSTRATED THAT ALL SURFACE WATER SAMPLING LOCATIONS ON HUBBARD BRANCH CREEK WERE BELOW THE TDEC SURFACE WATER DOMESTIC SUPPLY SCREENING LEVEL. EPA WAS CONTACTED ON 3/8/2023 (SAME DAY AS THE NRC NOTIFICATION) AS A COURTESY, AND AGAIN ON 3/27/2023. COLONIAL HAS ALSO VERBALLY COMMUNICATED WITH TDEC, IN ADDITION TO SUBMITTING WEEKLY WRITTEN REPORTS THAT HAVE BEEN OCCURRING SINCE THE INCEPTION OF EVENT IN 2022.