LINCOLN — The heavy Canadian oil that would flow in the proposed Keystone XL pipeline doesn't cause more leaks than lighter crudes, the National Academy of Sciences has determined.
A committee of 12 experts assembled by the National Academy released a report Tuesday that found diluted bitumen, the category of oil shipped from Alberta's tar-sands region, has no greater likelihood of causing pipeline failure than other oils. The committee reviewed pipeline incident statistics, reports, investigations and data on the chemical and physical properties of diluted bitumen.
The heavy tar-sands oil has been imported from western Canada for more than 30 years and transported in numerous pipelines in the United States, the report stated.
“There's nothing extraordinary about pipeline shipments of diluted bitumen to make them more likely than other crude oils to cause releases,” said Mark Barteau, a chemical engineering professor at the University of Michigan who chaired the report committee.
The study's conclusion was welcomed by supporters of the controversial Keystone XL project. But those who say the pipeline represents an unacceptable environmental risk criticized the study as too narrow in scope.
The Keystone XL pipeline would transport 830,000 barrels of tar-sands oil daily from western Canada to refineries on the Texas Gulf Coast. The 1,700-mile project, which would run through about 275 miles of Nebraska, is awaiting a decision by the State Department to determine whether it can be built.
Jane Kleeb, director of pipeline opponent Bold Nebraska, said the academy committee failed to assess whether the chemicals blended with the heavy oil to make it flow pose a greater threat to water supplies and human health if they leak.
She brought up pipeline ruptures that released thousands of barrels of diluted bitumen in Michigan and Arkansas since 2010.
“Moms in Michigan and Arkansas want this basic question answered: When a diluted bitumen pipeline spills, what are the health and economic risks to our families, land and water,” Kleeb said.
The Pipeline and Hazardous Materials Safety Administration, which sponsored the study, did not ask the committee to investigate whether diluted bitumen spills are more damaging or costly to clean up, Barteau said.
“The report was focused strictly on the likelihood of a release and not on the consequence of a release,” he said.
The heavy tar-sands oil has been imported from western Canada for more than 30 years and transported in numerous pipelines in the United States, the report says.
But most pipelines ship a variety of crudes and other petroleum products, which makes it hard to do a comparison between a pipeline that carries exclusively heavy oil with one that ships lighter crude, Barteau said.
Environmentalists had suggested that diluted bitumen oils contain higher concentrations of sediment and chemical agents that make them more corrosive to the interior steel walls of a pipeline. Pipelines that ship diluted bitumen also operate at higher temperatures than other pipelines, and some suspected that that could contribute to failures.
The study looked at acid levels, water content and amount of sediment in diluted bitumens and found no correlation with higher rates of internal or external corrosion. Nor are pipelines that carry diluted bitumen more vulnerable to external erosion, cracking or damage from mechanical forces, the study found.
Michael Whatley is executive vice president of the Consumer Energy Alliance, a strong proponent of the Keystone XL project. He said the report should put to rest any questions that diluted bitumen is inherently more dangerous to ship by pipeline than other oils.
“We are glad to have the backing of the National Academy of Science to knock down that argument,” he said Tuesday.
Those who criticize the study are trying to shift attention away from the fact that pipelines represent the safest way to transport oil, said John Stoody with the Association of Oil Pipelines.
“Now they're switching to the next argument,” he said.
Environmentalists, however, said federal pipeline regulators missed an opportunity to have the National Academy of Sciences measure the extent of damage to water, land and personal property from diluted bitumen spills. The examples in Arkansas and Michigan have been most troubling, said Anthony Swift, an attorney for the Natural Resources Defense Council.
“Unfortunately, the National Academy of Sciences findings shed no light on that question,” he said.