Courtesy: Suncor
Quick Facts

Q&A: Are exhaust plumes from the oil sands toxic?

It looks like smoke, but actually it’s mostly something both common and harmless: steam.


Andrew from Calgary asked, “Are exhaust plumes from oil sands facilities toxic smoke?”


We see it all the time — on television news, online, even social media: thick white exhaust plumes coming from stacks at oil sands facilities. People are often concerned about what’s in those plumes and assume it’s something toxic.

At oil sands facilities, exhaust comes from a variety of sources including power generation fueled by natural gas or petroleum coke, and flue gas desulfurization (FGD) units.

Petroleum coke is a by-product of the upgrading process. It is similar to coal but produces less ash and has higher energy content per ton. Burning coke produces sulfur dioxide (SO2), which is sent to the flue gas desulphurization process that removes 95 per cent of the SO2. The resulting exhaust from the FGD is mostly steam.

While oil sands facilities do emit greenhouse gases (GHGs), primarily carbon dioxide, in fact steam makes up the vast majority of visible exhaust. Water condensing from the steam in the exhaust streams appears white. The colder the air temperature, the more visible the steam exhaust becomes – just like you can see your breath on a very cold day.

Oil sands facilities and processes are designed and operated to reduce emissions. Emissions must meet regulatory standards, and are measured and reported to ensure compliance. There is also an extensive regional air quality monitoring network throughout the oil sands region.

In addition, oil sand facilities generate 30 per cent of the electricity produced in Alberta, using natural gas as the fuel. Operators are continuously working to reduce emissions. For example, one operator announced plans to replace coke-fired boilers with natural gas-fired cogeneration units that will reduce GHG emissions by approximately 25 per cent. The cogeneration units will eliminate the need for FGD, thus reducing the facility’s overall emissions of SO2 by about 45 per cent.

Oil sands production has been characterized as ‘dirty oil,’ but oil sands operators are committed and working to reduce all emissions. It’s noteworthy that emissions intensity across the industry has continued to decline. According to IHS Markit, oil sands emissions intensity has declined by 21 per cent since 2009. ‘Emissions intensity’ refers to the volume of GHGs emitted per barrel of oil produced.