TARGA DOWNSTREAM LLC

Incident Narrative

AT APPROXIMATELY 15:10 TARGA WAS CONTACTED BY 3RD PARTY OF A POSSIBLE PIPELINE LEAK. PERSONNEL WERE DISPATCHED TO SITE AND PIPELINE CONTROL ROOM WAS NOTIFIED OF POSSIBLE LEAK. TARGA PERSONNEL ARRIVED ON-SITE AND FOUND VAPORS SLOWLY LEAKING OUT OF GROUND WITH AN ICE SHEET ALONG THE PIPELINE RIGHT-OF-WAY. LINE WAS VERIFIED TO BE TARGA'S GATEWAY LATERAL USING MAPS, LINE LOCATOR & ICE SHEET MATCHED PROPERTIES OF PRODUCT BEING TRANSPORTED (HVL). ON-SITE PERSONNEL BEGAN MONITORING AREA FOR ANY UNSAFE CONDITIONS AND BASED ON RURAL LOCATION AND WEATHER CONDITIONS AT TIME OF LEAK THERE WERE NO THREATS TO PUBLIC SAFETY. OPERATIONS THEN BEGAN PROCESS OF SHUTTING DOWN PIPELINE TO STOP LEAK. DUE TO THE OPERATIONAL COMPLEXITY OF THE SYSTEM VARIOUS PROCESSES HAD TO TAKE PLACE TO TAKE THE PIPELINE OUT OF SERVICE SAFELY. DURING THIS TIME ON-SITE PERSONNEL CONTINUOUSLY MONITORED LEAK ENSURING AREA WAS KEPT SAFE. PIPELINE WAS SHUT IN AND EVACUATED OF PRODUCT USING NITROGEN AND PIGGING FOR REPAIR AND REMEDIATION PROCESSES TO BEGIN. DEFORMATION AND METAL LOSS INTEGRITY ASSESSED BY ILI WAS CONDUCTED ON 4/7/2022. FINAL ILI REPORT WAS ISSUED TO TARGA ON 6/6/22, 5 DAYS BEFORE LEAK OCCURRED, AND CONTAINED NO IMMEDIATE REPAIR CONDITIONS OR SRC'S. THERE WERE 60-DAY AND 180-DAY REPAIR CONDITIONS IDENTIFIED IN ILI REPORT. THE FEATURES IDENTIFIED WERE EXTERNAL & INTERNAL METAL LOSS ATTRIBUTABLE TO MANUFACTURING RELATED DEFECTS. ALL FEATURES FOUND BY ILI WERE WITHIN A 300-FOOT SECTION OF PIPELINE, THEREFORE TARGA ELECTED TO REPLACE AN ENTIRE 300-FOOT SECTION OF PIPE TO REPAIR ALL FEATURES AND TO PREVENT RECURRENCE OF POSSIBLE LEAK. ADDITIONALLY, TARGA HAS INITIATED 3RD PARTY INVESTIGATIONS REGARDING INTERNAL & EXTERNAL METAL LOSS FEATURES PLUS AN ADDITIONAL ILI RUN TO VERIFY ORIGINAL ILI RESULTS. AFTER INVESTIGATION, TARGA HAS CONCLUDED THROUGH PROCESS OF ELIMINATION THAT THE LEAK WAS CAUSED BY EXTERNAL CORROSION DUE TO DC INTERFERENCE. NO INTERNAL CORROSION WAS FOUND DURING METALLURGICAL ANALYSIS. DURING ROUTINE CATHODIC SURVEYS ON PIPELINE A 3RD PARTY PRODUCTION COMPANY RECTIFIER WAS FOUND INSTALLED WITH WIRING REVERSED CAUSING PIPELINE TO BECOME ANODIC AND THIS WAS CORRECTED PROMPTLY. AFTER PIPE WAS REMOVED FOR REPAIRS HOLIDAYS IN COATING WERE DISCOVERED WHICH EVENTUALLY LED TO LEAK IN PIPELINE. TO MITIGATE THIS FROM RECURRING TARGA HAS INSTALLED REMOTE MONITORING UNITS ON SECTION OF REPLACED PIPELINE TO MONITOR CATHODIC PROTECTION IN REAL TIME. WE HAVE ALSO INSTALLED 3 MAGNESIUM ANODES ON EACH SIDE OF REPLACED SECTION OF PIPELINE TO PREVENT CORROSION ON PIPELINE. ANOTHER MITIGATION COMPONENT IS THAT WE CONDUCTED A CLOSE INTERVAL SURVEY AND HAD A NEW AC INTERFERENCE STUDY COMPLETED ON PIPELINE TO VERIFY NO ADDITIONAL THREATS EXISTED. ADDITIONAL ILI RESULTS VERIFIED NO THREATS ON PIPELINE EXIST AFTER REPLACEMENT PIPE WAS INSTALLED BASED ON IMP PARAMETERS. HOWEVER, TO FURTHER MITIGATE POSSIBILITY OF PIPELINE CORROSION, TARGA HAS ELECTED TO DIG, VERIFY, AND REPAIR ALL ANOMALIES IDENTIFIED BY 2ND ILI RUN.