A U.S. government report indicating Canadian pipeline company Enbridge Inc. knew about cracks that led to a 2010 leak of more than three million litres of oil into a Michigan river is fuelling opposition in B.C.

The report by the National Transportation Safety Board found oil gushed from the rupture for more than 17 hours before the leak was discovered, and that Enbridge staff twice pumped more oil into the ruptured pipeline despite alarms and pressure differentials.

The report is raising alarm bells in B.C. and Alberta where an Enbridge proposal to build a $5.5-billion, 1,177-kilometre pipeline from the oilsands to the West Coast is being opposed by environmentalists concerned about the danger of oil spills.

NDP Leader Adrian Dix says the report is more evidence the province should block the Northern Gateway pipeline.

"The Kalamazoo pipeline rupture report showed that Enbridge was unprepared, its systems were inadequate, and proper procedures were not in place despite the various inspections and controls that are supposed to prevent these episodes and to contain them with minimal impacts if they do occur," said Dix.

'Makes me nervous'

Dix also criticized Premier Christy Clark for failing to take a clear stand on the issues.

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The oil began spilling into Talmadge Creek and spread throughout roughly 56 kilometres of the Kalamazoo River. (Rebecca Cook/Reuters)

"Premier Clark and the Liberal government have failed to fully participate in the National Energy Board hearings into the pipeline, missing the deadline to submit evidence and represent the interests of British Columbians," said Dix.

After the U.S. report was released, B.C. Environment Minister Terry Lake did say its conclusions don't sound good.

"We understand how British Columbians feel about the environment and the need to minimize, absolutely minimize, any potential risks and have contingency plans in place for any types of adverse events," he said.

"So when I hear stories like that of course it makes me nervous, as I'm sure it does all British Columbians."

But so far, Clark has refused to take position for or against the Northern Gateway pipeline, saying she wants to weigh the evidence presented to the federal joint review panel, which is currently conducting hearings on the pipeline proposal.

Taking responsibility

The three-member panel will release an environmental assessment of the contentious Northern Gateway pipeline project in the fall of 2013, several months after the May provincial election.

Enbridge spokesperson Paul Stanway says it's in the best interest of the company to avoid spills like the one in Michigan.

"The situation in Kalamazoo is getting close to being finalized and the clean-up is almost complete. Enbridge takes full responsibility for these incidents," he said.

The clean-up is already the most expensive onshore clean-up in U.S. history.

The oil spread into roughly 56 kilometres of the Kalamazoo River, fouling wildlife habitat and resulting in the closure of a large swath of the river to boaters and anglers. All but a few hundred metres of the river have since reopened.

"The bill for that will be somewhere north of three-quarters of a billion dollars, so this is obviously not something that any company would take lightly," Stanway said.

Security concerns

Meanwhile, the federal joint review panel has moved upcoming hearings to Smithers, B.C., because of what it describes as security concerns.

"They chose to go through Smithers instead of Hazelton," said spokesperson Annie Roy. "There's a limited number of people. The panel wanted to make sure they can come to the panel session in a secure environment and provide their views without having any issues with security."

In April, the same panel delayed hearings in Bella Bella after protests at the airport.

But Stikine MLA Doug Donaldson doesn't understand why the Hazelton hearings were deemed unsafe, and is calling on the National Energy Board to re-instate hearings in Hazelton.

"I must say that this is quite disappointing and a bit of an insult," said Donaldson.