Toxic emissions from the Canadian tar sands – already one of the dirtiest fossil fuels – have been dramatically underestimated, according to a study. Research published in the journal Science found that air pollution from the vast Athabasca oil sands in Canada exceed industry-reported emissions across the studied facilities by a staggering 1,900% to over 6,300%. Academics said this means that damaging reactive pollutants from the oil sands are equivalent to those from all other human-made sources across Canada with severe health implications. Keith Stewart, a senior energy strategist for Greenpeace Canada, said: “In quantifying the astonishing and largely unreported levels of health-damaging air pollution coming out of oil sands operations, these scientists have validated what downwind Indigenous communities have been saying for decades. This is making people sick, so our governments can and should require these companies to use some of their record-breaking profits to clean up the mess they’ve made.” Canadian tar sands, also called oil sands, are a massive site of oil extraction in the state of Alberta. They cover an area larger than England, are one of the biggest industrial projects on the planet, and have seen record production levels this year. The type of oil in the tar sands is called “bitumen”. It is extremely heavy and difficult to extract. Getting it from deep in the ground to the surface can use up massive amounts of water – enough to rival what a small city may use on a daily basis. Even more water and energy is needed to refine it for commercial use and the amount of climate-polluting greenhouse gases emitted per barrel of tar sands oil can be 30% higher than conventional oil. The study, published on Thursday, reveals the scale of air pollution caused by the process. Using aircraft to measure pollutants, it found that there are many organic compounds being released during the process that are missed by traditional ways of measuring air pollutants – with devastating health consequences. For decades Indigenous communities in the region have complained about the health impact of toxic air caused by the oil sands operations. Jesse Cardinal, from the indigenous led group Keepers of the Water, said the report confirmed what many communities had been experiencing for years. “We are told this is all within the limits and OK but this report backs up what the communities living in these areas experience – it is so bad they cannot open their windows because it hurts their lungs to breathe – especially at night.” The researchers examined emissions from surface mining operations as well as extraction from deeper deposits of bitumen. They noted the importance of post-extraction waste management practices, such as “tailings processing” where toxic sludge is left to dry. John Liggio, one of the research authors, said: “The study featured new measurements of total reactive organic chemicals onboard a research aircraft that reveal underestimated emissions by a factor of 1900% to over 6300% ... These emission underestimates were not just observed at the more well-known surface mining operations, but also from in situ extraction facilities that represent over 50% of production with projected increases.” The Canadian Environment and Climate Change ministry has been contacted for comment.