An oil tanker fed by Enbridge's oil sands pipeline will almost certainly spill sometime over the project's life, concludes a new Simon Fraser University report contesting the company's own risk projections.

"The problem with the Enbridge risk assessment," co-author Dr. Thomas Gunton, director of SFU's Resource and Environmental Planning Program, said in a release, "is that it does not accurately or clearly report the degree of risk involved with the Northern Gateway project."

Gunton relied on the United States Oil Spill Risk Analysis, a respected modeling system. His study predicted that "the probability of a marine tanker oil spill" is somewhere "between 95.3% and 99.9%" during the project's operation.

Enbridge, Gunton said, has calculated the probability of an oil tanker spill at 18 per cent.

The SFU researcher also takes issue with Enbridges estimate of a tanker spill once every 250 years -- Gunton said a coastal spill each decade is more likely.

Gunton claims that Enbridge's risk assessment contains 28 "deficiencies", including underreported tanker incidents, lack of bigger picture analysis and key assumptions based on unclear data.

His conclusion: "Enbridge understates the risk of spills from [Northern Gateway]."

The Calgary-based pipeline firm has not yet issued a public response to Gunton's report, which also authored by PhD candidate Sean Broadbent.

A tanker safety video on the Northern Gateway website, however, describes Douglas Channel as "a safe well-traveled passage from Kitimat to the Pacific Ocean that tankers have been using for decades."

It adds: "Only modern ships fitted with state-of-the-art navigation, communication and environmental monitoring equipment will be allowed at the new terminal."

Predicting oil spills is an inherently imprecise task. The SFU study notes that, "estimating risk is challenging due to the many uncertainties involved and that different assumptions and methodologies will produce different assessments of risk."

Geoff Dembicki reports for The Tyee.