The leak from Imperial Oil’s tailings pond in Alberta spilled over 5.3 million litres of toxic wastewater into the environment. Oil production in Canada’s tar sands is unsafe and harms biodiversity and downstream Indigenous communities. Tailings ponds are industry-made reservoirs the size of lakes in which the toxic byproduct of oil extraction from tar sands is stored. They have been growing and leaking for decades. This fact sheet highlights key facts regarding tailings size, growth, toxicity, seepage, financial liability and government failures.