Keystone Pipeline Rupture Investigation

Abstract

The National Transportation Safety Board coordinated with the Pipeline and Hazardous Materials Safety Board to investigate the November 16, 2017, rupture of Keystone Mainline number 1 crude oil pipeline operated by TransCanada Oil Pipeline Operations, Incorporated. The rupture resulted from a fatigue crack that initiated from near-surface cracks associated with sliding contact damage at the top of the pipe and propagated to failure within 7.4 years of pipeline operation. The surface damage was characterized by photography, scanning electron microscopy, energy-dispersive x-ray spectroscopy, metallography, and dimensional analyses, and findings indicated the damage was produced by contact with a steel component likely from a vehicle used during the original construction after the pipeline was positioned in the trench.