Investigators have pinpointed a common pipeline construction technique as the possible cause of a November spill in TransCanada Corporation’s Keystone pipeline that polluted a section of South Dakota prairie with some 5,000 barrels of diluted bitumen last month.
State regulators ordered the Calgary company to suspend shipment through the seven year-old, 590,000-barrel-per-day line, shortly after the leak was spotted November 16. Last week, TransCanada was allowed to resume pumping dilbit and other petroleum products at 80% of the line’s normal capacity.
That allowance, and the line’s underlying permit, may now be in jeopardy, after the U.S. Pipeline and Hazardous Materials Safety Administration (PHMSA) determined that a failure which “may have been caused by mechanical damage to the pipeline and coating associated with a weight installed on the pipeline [during construction] in 2008…was likely the cause of the spill.”
Weights are commonly installed on buried pipelines that run through areas of seasonally high water tables to keep them from floating to the surface. An unknown number of weights will have been installed along the 3,456-kilometre length of the original Keystone line—and would likely have been contemplated for the much bigger Keystone XL line.
“I’m anxious about the future operation of the pipe and the potential for future leaks,” said Gary Hanson, vice-chair of the South Dakota Public Utilities Commission. “If damage was caused by a weight in one location, similar damage could have been caused elsewhere. [And] if there is a standard installation procedure for installing the weights, that may have created challenges in other locations on the pipe.”
“Groundwater moves into this area and out of this area. Obviously, TransCanada recognizes that, because they put weights on the pipe,” Hanson added. “It concerns me as to future leaks and the potential for damaging groundwater.”
State regulators “reiterated their right to shut the pipeline down” if they remain unsatisfied about its safety, InsideClimate News reports.
TransCanada is currently weighing whether to proceed with the long-troubled Keystone XL—an extra-large pipe that would loosely parallel the original Keystone’s route.
Last month, the Nebraska Public Utilities Commission gave the company crucial permission to build the line through that state—but along a route it had not preferred. Last week, TransCanada CEO Russ Girling said he remained “encouraged” about XL’s completion. But Girling declined to confirm his company was ready to proceed with construction while it digests its latest regulatory setbacks.
Meanwhile, Reuters suggests the PHMSA’s findings will echo far beyond South Dakota, and TransCanada’s troubled Keystone lines.
“The regulator’s finding has implications for the [Keystone] pipeline and others throughout the world,” Reuters observes. “The weights, which tip the scales at 3,175 kilograms or more, are commonly used, but only pipeline operators know where they are located.”
Such damage “could happen on other segments of this pipeline, and other pipelines,” University of Southern California civil and environmental engineer Najmedin Meshkati told the news agency.
“Depending on the results of the full investigation, construction plans for new lines such as the Keystone XL may need modification,” Reuters speculates. “Existing lines may also have to be checked, a difficult and potentially expensive undertaking.”