ALYESKA PIPELINE SERVICE CO

Incident Narrative

ON MAY 29, 2015, AN EXCAVATION CREW IDENTIFIED A WEEP IN A BELOW-GROUND ISOLATION FITTING INSTALLED ON THE TAPS 48-INCH MAINLINE AT PS10, ADJACENT TO BL2. (THIS WAS IN A SEPARATE, ADJACENT LOCATION FROM WHERE THE EXCAVATION WORK WAS LOCATED; WORK ON THE DIG WAS SUSPENDED WHEN THE WEEP WAS SIGHTED.) THE PURPOSE OF THE ISOLATION FITTING WAS TO ELECTRICALLY ISOLATE THE MAINLINE AND FACILITY PIPING CATHODIC PROTECTION SYSTEMS TO PROVIDE OPTIMAL CORROSION PROTECTION. THIS FITTING WAS INSTALLED DURING INITIAL CONSTRUCTION. CURRENTLY, THE ISOLATION FITTING IS NOT NEEDED DUE TO UPGRADES TO THE CATHODIC PROTECTION SYSTEMS, AND IT HAS BEEN ELECTRICALLY BYPASSED. PS10 HAS BEEN OUT OF SERVICE SINCE 1998 AND WAS STRAIGHT PIPED IN 2013. INITIAL REPORTS CONCERNING THE WEEP WERE THAT THE SUBSTANCE WAS POTENTIALLY CRUDE AND A SPILL REPORT WAS FILED. HOWEVER, DUE TO THE ABSENCE OF LOWER EXPLOSIVE LIMIT (LEL) GAS MEASUREMENTS AND OTHER CHARACTERISTICS INCLUDING THE PRESENCE OF TAR-BASED PACKING MATERIAL IN THE ISOLATION FITTING, THE PRECISE NATURE OF THE SUBSTANCE WAS INITIALLY UNCLEAR. THUS ALYESKA SENT A SAMPLE OF THE SUBSTANCE FROM PS10 AND A SAMPLE OF NORTH SLOPE CRUDE OUT FOR A LABORATORY ANALYSIS. TEST RESULTS RECEIVED JUNE 4, 2015, INDICATE THE WEEPING MOISTURE ON THE ISOLATION FLANGE AT PS10 IS WEATHERED CRUDE OIL. INITIALLY, THE WEEP RATE WAS ABOUT ONE DRIP PER SECOND, APPARENTLY DUE TO THE ACCUMULATION OF CRUDE WITHIN THE TAR MEMBRANE/PACKING MATERIAL WITHIN THE FITTING. THE ORIGINAL WEEP LATER STOPPED ON ITS OWN, BUT THERE IS NOW ADDITIONAL MINOR WEEPING. ALYESKA HAS EXCAVATED APPROXIMATELY 5 YARDS OF CONTAMINATED SOIL. ALL EXCAVATION HAS BEEN DONE BY HAND THUS FAR. THERE IS NO INDICATION HOW LONG THE WEEP HAS BEEN ACTIVE AND THE TOTAL VOLUME EXTRUDED IS UNCERTAIN. TECHNICAL SOLUTIONS FOR REPAIR AND REMEDIATION ARE BEING EVALUATED. CONTINGENCY SPILL MEASURES HAVE BEEN PUT IN PLACE, INCLUDING 24-HOUR SITE MONITORING; SECONDARY CONTAINMENT (PIPE CAP); STAGING OF A CREW WITH A VAC TRUCK; AND PLACEMENT OF AN RB-100 (ACTUATOR) AND GENERATOR ON-SITE FOR CONTINGENCY CLOSURE OF THE VALVE. PROTOCOLS ARE ALSO BEING DEVELOPED FOR ASSESSMENT OF OTHER ISOLATION FITTINGS (21) LOCATED ALONG THE TAPS SYSTEM. UPDATE: ON JULY 13, 2015, A 60-INCH CONTAINMENT SLEEVE WITH GROUT INJECTION AND SEAL WELDING OF PLUGS WAS COMPLETED. THE WEEP IS REPAIRED THOUGH ALYESKA HAS FINAL INSTALLATION OF CONICAL ENDS FOR THE SLEEVE SCHEDULED FOR THE END OF SEPTEMBER 2015. ALYESKA HAS CONTRACTED STRESS ENGINEERING TO CONDUCT A CAUSE ANALYSIS FOR THIS EVENT. ALYESKA CONTINUES INVESTIGATIONS OF OTHER ISOLATION FITTINGS ON TAPS TO ENSURE NO OTHER FAILURES HAVE OCCURRED. TO DATE, SEPTEMBER 10, 2015, NO ADDITIONAL LEAKS HAVE BEEN IDENTIFIED. UPDATE: THE CONICAL ENDS INSTALLATION WAS COMPLETED IN OCTOBER 2015. UPDATE: THE ROOT CAUSE INVESTIGATION FOR THIS INCIDENT WAS COMPLETE ON MARCH 1, 2016. THE CAUSE OF THIS INCIDENT WAS DETERMINED TO BE ATTRIBUTED TO BOTH POST CONSTRUCTION SETTLING CAUSING THE PIPE TO BEND, COUPLED WITH A 7.9 EARTHQUAKE IN 2002 CENTERED 3 MILES FROM THE PIPELINE. ALYESKA HAS DETERMINED THAT IT IS HIGHLY UNLIKELY THAT OTHER ISOLATION FITTINGS ON TAPS HAVE BEEN SUBJECT TO THESE CONDITIONS AND IN GENERAL THESE ISOLATION FITTING ARE ROBUST.