TC OIL PIPELINE OPERATIONS INC

Incident Narrative

ON 2 APRIL, 2016, A RELEASE OF OIL WAS REPORTED, AND CONFIRMED, AT MP 411, OR FREEMAN PS+4. A CONTRIBUTING FACTOR TO THE LEAK APPEARS TO BE CONSTRUCTION RELATED, ASSOCIATED WITH A FAILED PIPELINE GIRTH WELD. APPROXIMATELY 220 BARRELS OF CRUDE HAS BEEN SPILLED; REMEDIATION IS CONTINUING AT THE TIME OF THIS INITIAL REPORT. PRELIMINARY AND FINAL METALLURGICAL ANALYSIS HAVE BEEN PERFORMED. INTEGRITY VERIFICATION WORK HAS BEEN CONDUCTED AND COMPLETED. RCFA: A METALLURGICAL FAILURE ANALYSIS OF THE WELD WAS PERFORMED FOR TRANSCANADA BY AN INDEPENDENT THIRD PARTY APPROVED BY PHMSA . THE FAILURE ANALYSIS IDENTIFIED THAT THE CRACK INITIATION AND PROPAGATION MECHANISMS OCCURRED AT ELEVATED TEMPERATURE IMPLYING THAT THE CRACK FORMED DURING THE WELDING PROCESS. EVIDENCE TO SUPPORT THIS STATEMENT INCLUDES HIGH-TEMPERATURE OXIDES FOUND ON THE FRACTURE SURFACE AND METALLOGRAPHIC IMAGES APPEARING TO SHOW HOT TEARING IN THE VICINITY OF THE MAIN CRACK. THE CRACK INITIATED AT AN ISOLATED WELD DEFECT AT THE TOE OF THE ROOT OF THE WELD AT THE 6 O'CLOCK POSITION ALONG THE INNER DIAMETER (ID) OF THE GIRTH WELD AND PROPAGATED THROUGH WALL DURING THE WELDING PROCESS. OVERALL, THE LEAK WAS CAUSED BY A THROUGH-WALL CRACK 3-11/16 INCH LONG AT THE OUTER DIAMETER (OD) BY 6.2 INCH LONG AT THE ID. FRACTURE SURFACE EROSION MARKINGS REVEALED TWO LEAK PATHS CORRESPONDING TO THE LOCATION OF THE LEAKS OBSERVED IN THE FIELD AND DURING LABORATORY TESTING. THE LENGTH OF THE LEAK WAS SMALL, MEASURING APPROXIMATELY 17% OF THE OVERALL CRACK LENGTH AT THE OD. IT WAS POSTULATED THAT THE NON-LEAKING AREA OF THE THROUGH-WALL CRACK MAY HAVE BEEN TOO NARROW FOR OIL OR WATER TO FLOW. 20160823 UPDATE: CORRECTED LAT/LONG COORDINATES TO PROPER FORMAT. 20161207 UPDATE: DEPTH OF COVER UPDATED, PIPE SEAM TYPE DEFINED, COSTS REPORTED, AND RCFA UPDATED (ABOVE). 20,428.52 TONS OF SOLID MATERIALS WERE REMOVED FROM THE SITE, AND 1,174.25 TONS OF LIQUID WASTES WERE DISPOSED OF. 20170125 UPDATE: CHANGED VOLUME TO 400 BARRELS TO MATCH AMOUNT REPORTED TO NRC AND OTHER GOVERNMENT AGENCIES.