The study by Tom Gunton, director of the resource and environmental planning program, said the risk analysis submitted by the company to a federal review panel has many deficiencies, including using data that under reports tanker incidents.
"Enbridge makes no attempt to adjust for this underreporting and consequently underestimates the probability of tanker spills," Gunton said in a statement with the release of the report.
Gunton's analysis found the likelihood of a tanker spill ranges from one every 23 years to one every 196 years — higher than the one every 250 years estimated by Enbridge (TSX:ENB).
It said a significant oil spill at the tanker terminal that would be built in Kitimat, B.C., as part of the project is possible once every 15 to 41 years, compared to the company estimate of once every 62 years.
And there are likely to be 15 to 16 pipeline spills a year on land, compared to Enbridge's estimate of one every two years, said the study released Thursday.
John Carruthers, president of Northern Gateway Pipelines, said the report is misleading.
He pointed out that Gunton appeared as a witness at federal review panel hearings for Coastal First Nations, a group that opposes the pipeline, but did not submit the report for review by the panel.
"All of Northern Gateway's conclusions have been subject to peer review, information requests and questioning by interveners and the Joint Review Panel," Carruthers said in an email.
The study was released days before the questioning phase of the hearings comes to an end and too late to be submitted, he said.
"Given the timing, we can only conclude this study was purposely kept off the evidence record to avoid being tested in the hearing process," he said.
The spill numbers are inflated, Carruthers said, and the study does not reflect the new technology proposed for Northern Gateway.
"Their study results are not borne out by real world tanker spill statistics. Based on Gunton’s estimates we should expect 21 to 77 large spills every year worldwide while in reality after 2000 it has been below 3, and in 2012 was zero," Carruthers said.
The report by Gunton, a former deputy minister of environment for a provincial NDP government, and Sean Broadbent, acknowledged that estimating risk is challenging because of the uncertainties involved, however, it concluded that Northern Gateway's assessment is not accurate.
"The risk assessment in this report also concludes that the (Enbridge Northern Gateway Pipeline) has a very high likelihood of a spill that may have significant adverse environmental effects," it said.
The review panel weighing the pipeline is expected to wrap up the questioning phase of hearings in Prince Rupert this weekend, and final arguments will begin in Terrace in June.
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