The number of tanker and pipeline spills from the Northern Gateway project will be much higher than Enbridge has estimated if it goes ahead, say Simon Fraser University researchers in a new study.

The report, released Thursday, looked at three components of the $6.5-billion megaproject: the pipeline through B.C., the marine terminal in Kitimat and tankers.

Using an oil spill risk assessment model employed by the U.S. government, researchers concluded that the chance of a marine tanker spill is between 93 and 99 per cent over the operating life of the project, or 30 to 50 years.

That's higher than the 18 per cent estimated by Enbridge, says the study's lead author Dr. Tom Gunton, director of the School of Resource and Environmental Management at SFU.

The study also found the number of spills along the 1,160 kilometres of pipeline would be dramatically higher, up to 15 pipeline spills per year, compared with Enbridge's estimate of one spill every two years.

That data was based on Enbridge's own pipeline spill record from 2002 to 2010, said Gunton.

"What we found was there were 28 deficiencies in (Enbridge's) risk assessment model. The database Enbridge used under-reports the number of tanker incidents by between 38 and 96 per cent," he said.

"They made no attempt to correct that under-reporting."

The other problem with Enbridge's risk assessment, said Gunton, is that it fails to use the standardized model used by the U.S. government.

The U.S. Oil Spill Risk Analysis model, which was developed in 1975 by the federal government, and is used by companies around the world to evaluate offshore oil-spill risks.

Gunton said this study highlights the need for the Canadian government to follow its American counterpart and conduct its own spill assessment of large oil projects. In Canada, the project developer conducts the risk assessment, which Gunton said raises concerns of bias.

He admits that forecasting future trends is tricky, but he said risk studies need to convey the uncertainty and range of risk involved.

"One of the lessons from all of this is that we need to eliminate the potential bias and have impact assessments done by independent scientists."

John Carruthers, president of Enbridge Northern Gateway Pipelines, dismissed Gunton's report, saying that he did not take into account new technologies such as double-hulled ships, improved ballast coating and better procedures, such as reducing speed and using tugboats. He also said Environment Canada, Transport Canada, the Canadian Coast Guard and the Department of Fisheries all reviewed the methodology used by Enbridge.

"They all agreed that the methodology was acceptable," he said, adding that Enbridge didn't use the U.S. risk assessment model because it doesn't take into account all the technical advancements that mitigate risk.

"We recognized that (spills) would be a key issue," he said. "All of the conclusions that we provided (to the joint review panel) were subject to scrutiny at the hearing."

Gunton said some of the mitigation measures, such as double-hulled ships and tug escorts, are incorporated into the U.S. assessment model.

The review panel weighing the pipeline is expected to wrap up hearings in Prince Rupert this week, and final arguments will begin in June.

ticrawford@vancouversun.com