SHELL PIPELINE CO., L.P.

Incident Narrative

EVIDENCE OF EXTERNAL CORROSION AT RUPTURE POINT. PIPE IS CURRENTLY AT A THIRD PARTY LABORATORY FOR FULL METALLURGICAL TESTING TO DETERMINE CAUSE AND CONTRIBUTING FACTORS. NOTE: NRC - NOTIFICATION TO THE NRC WAS INITIALLY MADE AT 16:46 11/16/2010. NO INFORMATION OF LOCATION OR VOLUME WAS KNOWN. THE NRC SAID TO CALL BACK WHEN MORE INFORMATION IS KNOWN AND A REPORT NUMBER WILL BE GIVEN. SECOND CALL TO THE NRC WAS DONE AT 18:10 11/16/2010 WITH THE LOCATION OF THE RELEASE AND A WORST CASE SCENARIO VOLUME. THIRD CALL TO THE NRC WAS DONE AT 12:20 11/18/2010 WITH THE RELEASE VOLUME. 3/23/2011 - METALLURGICAL INVESTIGATION OF THE RUPTURED PIPE SHOWED THAT THE LINE SUFFERED FROM LOCAL EXTERNAL CORROSION AND FAILED AT THE EXTRADOS OF A FIELD BEND. FURTHER INSPECTION REVEALED THAT THE LONGITUDINAL CHARACTER OF THE CORROSION FEATURES MADE THE LOCATION SUSCEPTIBLE TO FATIGUE CRACKING AS A RESULT OF OPERATIONAL PRESSURE FLUCTUATIONS, WHICH LED TO THE ULTIMATE FAILURE OF THE PIPE. THE PIPELINE HAS A COAL TAR CORROSION COATING WHICH COULD BE PRONE TO SHIELDING FROM THE CATHODIC PROTECTION SYSTEM IN CASE OF DISBONDMENT FROM THE STEEL PIPE. THE LEVEL OF CORROSION DID SUGGEST SHIELDING WAS HAPPENING AT THIS PARTICULAR LOCATION. 2/28/2013 - REQUESTED BY PHMSA TO RE-SUBMIT WITHOUT THE INTENTIONAL RELEASE VOLUME. REMOVED THE 526 BBLS AND ADJUSTED THE RECOVERED VOLUME FROM 1021 TO 495 BBLS. REQUESTED BY PIYALI TALUKDAR, OPS PHMSA USDOT.