There is no more risk of an oil spill in coastal waters in BC than there is of a spill by the 2 tankers carrying Alberta crude oil from Montreal to Quebec on a daily basis. 
Quebec mayors have no objection to the 2 tankers because they are owned by a Quebec company, and the crews are Quebecers.
The risk of a crude oil spill in BC waters is less than the risk of a bunker oil spill from all the cargo ships and tugs in the same waters.