Energy giant Enbridge’s plan to reverse the flow and increase the capacity of a pipeline – has won the approval of the National Energy Board.

Line 9 has been running between southern Ontario and Montreal for years.

Opponents have argued the Line 9 plan – which involves transporting a heavier form of crude – puts communities at risk, threatens water supplies and could endanger vulnerable species in ecologically sensitive areas.

The decision on the controversial pipeline comes some four months after the federal regulator held public hearings on the Calgary-based company’s proposal.

The board says its decision enables Enbridge to react to market forces and provide benefits to Canadians, while simultaneously implementing the project in a “safe and environmentally sensitive manner.”

Line 9 originally shuttled oil from Sarnia, Ontario to Montreal, but was reversed in the late ’90s – in response to market conditions to pump imported crude westward.

The NEB decision is subject to certain conditions and requirements.