Spill blamed on failure to locate buried pipeline

Failure to properly assess the location of a buried Enbridge pipeline led to a construction mishap that released 1,000 cubic metres of crude oil condensate last year in Strathcona County, the Transportation Safety Board of Canada said Monday.

The spill on Feb. 17, 2017, occurred as crews from construction contractor Ledcor were working in the area of a pipeline crossing just west of Anthony Henday Drive and north of 92 Avenue. In installing TransCanada’s new Grand Rapids Pipeline, the crews punctured Enbridge’s Line 2.

In its investigation report, the Transportation Safety Board found that the drilling of a path for the new pipeline had occurred without properly confirming the location and depth of the Enbridge line. An access ramp for heavy vehicles had been installed over the crossing, and it was not removed to allow crews to take field measurements of Line 2, the report said.

Instead, measurements from an adjacent pipeline were used to assume the depth of the Enbridge line.

The TSB report noted that these depth assumptions had been highlighted in colour on project documents to signal that field verification had not taken place. However, this was not part of Ledcor’s established communications process.

“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,” the agency said in a news release. “As a result, there were missed opportunities to further assess the drill path.”