"It's a technical question. Normally, when you have a credible environmental regulation system, this kind of thing can be observed, but there is no system of environmental regulation in Canada, with Stephen Harper. So, people have to say 'no' to this, because you absolutely cannot trust them to produce a result that is safe for the environment." Mulcair said in an interview.

Enbridge has applied to the National Energy Board to change Line 9's flow direction, so it can carry western oil eastward. It also wants to boost the flow to 300,000 barrels a day of either conventional crude or diluted bitumen (called dilbit) from the Alberta oilsands.

Environmentalists have decried the federal government's scaling back of environmental regulation. Environmental Defence and Greenpeace Canada argue that "the application is very difficult to find online" and "the basis on which participants will be rejected or accepted is unclear."