Enbridge (TSX:ENB) officials confirm the spill response plan they have filed with the federal review panel studying the pipeline proposal deals with conventional crude, not specifically the diluted bitumen the pipeline will carry.
But Enbridge says the two react the same way once spilled.
However, documents obtained under access to information show a scientist at the Department of Fisheries and Oceans argued vigorously for a chance to do more research.
Kenneth Lee submitted a research proposal last December saying the matter requires further study because Enbridge's plan had "strong limitations due to inaccurate inputs."
"The Northern Gateway pipeline proposal lacks key information on the chemical composition of the reference oils used in the hypothetical spill models," wrote Lee, head of DFO's Centre for Offshore Oil Gas and Energy Research, or COOGER.
Lee sought approval to conduct a series of studies through to 2015, when final tests on the "toxic effects of reference oils to marine species" would be completed.
That deadline suggests the results would come too late for the Northern Gateway review panel as it reviews the environmental impact of the pipeline. Its hearings end next April and the panel reports back to government by the end of next year.
Lee noted his research would also be used by the Canadian Coast Guard, the agency that would be in charge of overseeing a spill into Canada's waters.
He wrote the Coast Guard is "uncertain" whether traditional methods to contain an oil spill and clear contaminated water would be effective if deployed in a Northern Gateway spill.
The Fisheries Department did not respond to questions about whether Lee's group was given the go-ahead to do the research.
Lee was informed this spring that his job and the research centre he runs is at risk of being eliminated as a result of federal budget cuts.
Reached by phone, Lee said he was not authorized to comment on the proposal but confirmed that he and his staff have been notified their positions are on a list of positions that could be cut.
"We were on an affected (position) list at one point. And we're still on that affected list, but COOGER will still exist."
Lee is an internationally renowned expert on oil spills and was tapped last year to join a U.S. scientific committee studying the aftermath of the 2010 Gulf of Mexico oil spill.
Northern Gateway's twin pipelines would carry natural gas condensate to Alberta and diluted oilsands bitumen to Kitimat, B.C., where it would be transferred to tankers for export.
Opinions differ on whether a spill of diluted bitumen would react so dramatically differently from spills of other crudes.
Bitumen is oil extracted from oil sands. It's thick and heavy like molasses, though a diluted version is what would be moved through the Enbridge pipeline if the $6-billion project gets approved.
That's about all everyone — including Calgary-based Enbridge, the B.C. government, pipeline engineers, spill response experts and environmentalists — can agree on.
What they cannot agree on is whether characteristics believed to be associated with diluted bitumen — also known as dilbit — lead to higher risks of pipeline fractures and consequently, oil spills.
There is also no agreement on whether diluted bitumen behaves differently in water than conventional crude oil once it is spilled.
Ray Doering, manager of engineering with the Northern Gateway project, and Elliott Taylor, one of the company's oil spill experts, said a combination of factors, over time, will prompt diluted bitumen to get denser.
For example, when the lighter properties evaporate, the heavier stuff remains, so it may sink. Or turbulent water or wave action could cause it to sink. Or if the oil gets mixed with sand or sediment — like it probably would in a river or a stream, or close to a shoreline — then it would sink.
But both say that's true of all crude.
"The toolbox that is going to be put together for this project will start with the same type of equipment that you use for any type of oil spill because we know that initially, that behaviour is going to be just like any other crude oil," said Taylor, a marine geologist and oil spill response expert with Polaris Applied Sciences.
"If it gets into water it’s going to float, so you would use the same techniques as long as those techniques are effective and address the behaviour of the oil at that stage.
"If it does get heavier, as it weathers and picks up some of those sediments, whether that’s at the shoreline or in the river, we would still go after that."
But the Natural Resource Defence Council, a U.S environmental group, argues dilbit has a higher acid concentration than conventional crude oil.
It also maintains that even when diluted, dilbit is still more viscous than conventional crude. To keep the crude fluid, the pipeline transporting the product will then have to operate at a higher temperature, said policy analyst Anthony Swift.
"In general, higher temperatures increase the rate of chemical reactions," he said in an interview. "In addition to internal corrosion, a pipeline operating at higher temperature is also going to increase the rate of external corrosion."
Swift points to the July 2010 spill where an Enbridge pipeline rupture caused millions of litres of crude to spill into the Kalamazoo River in Michigan. The U.S. National Transportation Safety Board concluded the rupture was caused by cracks in the pipeline due to corrosion that wore away the pipeline's protective coating.
But what exactly caused the corrosion still needs to be thoroughly examined and until it is known, due diligence is needed, Swift said.
"The real question is — and it's a question that hasn't been clearly evaluated by regulators — does the combination of higher acid content and higher pipeline operating temperature pose a long-term risk to pipelines due to internal corrosion?" he said.
Enbridge refutes all of the Natural Resource Defence Council's claims.
"We know from our own data that there are no higher levels of internal corrosion associated with diluted bitumen than there would be for any other type of conventional oil that we move," said Doering.
"There are no differences to external corrosion either because those conditions don't change."
Doering added that all products that move through a pipeline must be of a certain viscosity in order for it to be "pipelineable."
As a result, the temperature set for transporting diluted bitumen would be the same as for moving all other types of crude.
"It operates at normal temperatures because it has been diluted with condensate or diluant (light hydrocarbon product), so it has the same properties as conventional oil," he said.
"It doesn't need to operate at higher temperature and higher pressures."
A study done for Alberta Innovates Energy and Environment Solutions, a government-funded research and development agency, in 2011 appears to support Enbridge's claims.
Jenny Been, a corrosion engineer, compared data for four types of dilbit crude with heavy, medium and light conventional Alberta crude oils.
Still, the B.C. government maintains that if a marine spill were to happen along the West Coast, diluted bitumen is more likely to sink than conventional crude oil.
"A greater degree of difficulty is involved in recovering bitumen and more remediation is required should an unintended release occur, particularly once bitumen sinks into the water column or into soils," a technical analysis released by the government last month says.
The National Transportation Safety Board's report on the 2010 Michigan spill also found that two days after the spill, the denser oil fractions had sunk to the bottom of the river bed, prompting Enbridge to clean it up by gathering up the bottom sediments and disposing them.
In the spring of 2011, a reassessment still found a "moderate-to-heavy contamination of 200 acres (80 hectares) of the river bottom," the report said.
Enbridge acknowledged that some properties in spilled diluted bitumen could eventually sink.
"Initially, it will have the same behaviour as conventional crude oil," Doering said.
"Over time, the condensate — the diluant used to blend — can begin to evaporate and the property of the diluted bitumen becomes denser."
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