News release

In its investigation report (P17H0011) released today, the Transportation Safety Board of Canada (TSB) determined that a lack of field measurements to confirm the exact location of buried pipelines along a new horizontal bore hole path contributed to the striking and puncture of an Enbridge pipeline in Sherwood Park, Alberta. There were no injuries.

On 17 February 2017, a 20-inch Grand Rapids Pipeline GP Ltd. (GRP Ltd.) pipeline was being installed using a horizontal directional boring technique in an area where other pipelines were already in place. During its installation, the 24-inch Line 2 pipeline operated by Enbridge Pipelines Inc. (Enbridge) was struck and punctured during the boring operation. Approximately 1000 m3 of petroleum crude oil condensate was released. Most of the released product was recovered. The National Energy Board continues to monitor remedial actions on site, and to provide environmental oversight.

The investigation determined that the horizontal directional boring took place without a field-measured confirmation of the exact location and depth of cover for the Line 2 pipeline at the crossing with the GRP Ltd. pipeline. Measurements taken from an adjacent pipeline were used instead, which were highlighted within the project documentation to indicate that a field verification had not been completed. However, this was not an established process for communicating a deviation at Ledcor Pipeline Limited (Ledcor), the construction contractor. In addition, a ground disturbance checklist completed at the start of the shift incorrectly indicated that visual depth confirmation had been performed for all pipelines to be crossed. As a result, there were missed opportunities to further assess the drill path.

Following the occurrence, Enbridge initiated a review of internal communications, including clarifying and harmonizing technical terminology related to pipeline crossings. GRP Ltd. enhanced ground disturbance and pipeline crossing procedures and checklists, and issued further guidance to employees. Ledcor enhanced its procedures related to line crossings.