The biggest impacts of the tar sands developments are felt by the Canadian First Nation aborigine people.
They are losing their rights to hunt and fish in their homelands, because animals and fish alike are dying.
Cancer rates amongst the people that live downstream of the tailing ponds are reported to be far higher than 'normal', and there are a disproportionately large number of different types of cancer.(1)
In the USA, there has been local opposition to refining plants that will process the bitumen after it has been transported there through pipelines, due to concerns about air pollution and health impacts.(2)