The leak of what the port believes is bunker fuel was reported on Sunday when staff noticed a rainbow sheen near the tide line.
The port authority says the pipe passes under property it owns and ends next to the marine berth at the Westview Wood Pellet Terminal.
It says workers have excavated an area so they can flush and cap the pipe.
The port says it has engaged the Western Canada Marine Response Corporation to contain the fuel that reached the foreshore and the group is working to clean the shoreline and immediate area.
Officials have also called in an environmental consultant in to assess the potential impacts of the leak, although they believe there is "minimal risk to marine life and vegetation" and say only a "small quantity" escaped.