A recent string of leaks from tailings ponds at oil sands operations upstream has once again drawn attention to the profound transformation Canada’s largest industry has had on the region – and the distrust that comes with it. In May, Calgary-based Imperial Oil notified Alberta’s energy regulator it had discovered discoloured water near its Kearl oil sands project. The regulator soon concluded the water had come from tailings ponds where the company stored the toxic sludge-like byproducts of bitumen mining. Environmental samples showed high levels of several toxic contaminants, including arsenic, iron, sulphate and hydrocarbon – all of which exceeded provincial guidelines.

The Alberta government waited a month before calling an emergency response to one of the biggest releases of oilsands tailings in the province's history, a leaked document shows. The document, obtained by The Canadian Press, shows the province didn't initiate an emergency response until after First Nations chiefs in the area went public about how they were informed of the releases from Imperial Oil's Kearl mine, about 70 kilometres north of Fort McMurray, Alta.