Fact File: Claims higher ethanol fuel blends damage cars exaggerated, expert says

When the United States allowed the widespread sale of gasoline with increased ethanol content at the pumps as a temporary measure to relieve soaring prices, online posts claimed the blend of ethanol and gasoline known as E15 damages engines and offers poor fuel economy. In Canada, gasoline is required to contain a certain amount of renewable fuels such as ethanol, with the amount varying by province. E15, which contains 15 per cent ethanol, isn’t widely available in Canada. But an expert says the blend is not damaging to vehicles produced after 2001 and claims about poor fuel efficiency lack context.

THE CLAIM

As Iran continues to block tanker traffic through the Strait of Hormuz — a key oil and gas shipping route that has been essentially cut off after the United States and Israel attacked Iran in February — drivers around the world are seeing higher prices at the pumps.

The price surge price led the U.S. Environmental Protection Agency on March 25 to temporarily allow countrywide sales of gasoline blended with 15 per cent ethanol. But that decision sparked several online claims by Canadians and Americans about the addition of E15 fuel to gas pumps and its effect on vehicles.

“Hey Canada, E15 fuel is being added to the gas stations and they want to add higher blends by 2030. This is going to be destroying gas-powered vehicles and making it almost sure that you will be buying an electric car,” says the creator of an April 10 TikTok video.

A March 30 Instagram post with around 35,000 likes claimed E15 can damage vehicles built before 2021 and that the gas, while cheaper, burns faster and “won’t last.”

Posts on TikTok and Threads framed E15 as a gas “thinner” and claimed it has worse fuel economy, meaning drivers have to fuel up sooner.

THE FACTS

Canada’s federal renewable fuel regulations require that fuel producers and importers have an average “renewable content” of at least 4 per cent, “based on the volume of gasoline that they produce or import.”

The government views renewable fuels such as ethanol and biodiesel as beneficial to the environment because they produce fewer greenhouse gas emissions than gasoline or diesel.

E15, however, isn’t yet widely available at Canadian pumps.

Under the country’s Clean Fuel Regulations, importers of liquid fossil fuel to Canada are expected to “gradually reduce the carbon intensity” of gasoline and diesel sold in Canada by a certain amount each year until 2030. Individual provinces have their own requirements for renewable fuels.

Since last year, gasoline sold in Ontario has to include an 11 per cent blend of renewables, which will increase to 13 per cent in 2028 and 15 per cent in 2030.

Alberta’s requirement is five per cent, Saskatchewan’s is 7.5 and Quebec requires 10 per cent, with the goal of increasing to 15 by 2030. Manitoba requires 10 per cent ethanol in gasoline, Saskatchewan requires 7.5 per cent and British Columbia five per cent.

Bradley Saville, a professor in the department of chemical engineering and applied chemistry at the University of Toronto, said in an email that fears E15 could damage vehicles are exaggerated.

“Ethanol blends up to E15 have been approved for use in all vehicles made since 2001,” he said, referring to U.S. Environmental Protection Agency findings. He added that E15 is fully warranted by most automakers.

Mazda had been an exception, with owner’s manuals advising that gasoline containing more than 10 per cent ethanol could damage the vehicle. But in a May 27 email, Mazda Canada’s product communications manager Chuck Reimer said the automaker now considers E15 safe for models going back to 2013. Reimer said the company will be updating its online manuals to specify that if 10 per cent ethanol fuel is not available, “gasoline with ethanol blends up to 15 per cent … is supported and will not damage your vehicle when applicable fuel-quality standards are met.”

While drivers of vehicles made before 2001 might need to worry about damage, it’s typically limited to certain parts of the fuel system and not the engine itself as some posts claimed, Saville said.

E15 can also damage smaller engines such as the ones found in lawn mowers, motorboats and snowmobiles. Bombardier Recreational Products, a Canadian manufacturer of recreational vehicles including Ski-Doos, recommends that customers avoid using E15 because it could damage the engine “of any recreational vehicle.”

Generally, the use of oxygenated fuel such as ethanol “is not a problem,” the company said on its website, “but leaving this fuel in the machine for more than 30 days can create a problem.”

It’s true that fuel containing ethanol has a slightly lower fuel economy because of its lower energy content.

In a report on E10 fuel performance, Natural Resources Canada said that while the blend contains 97 per cent of the energy of pure gasoline, it provides “improved combustion efficiency” that compensates for the difference.

“Overall, use of low-blend increases fuel consumption by an average of 2 per cent compared with pure gasoline. However, this is only a slight difference when compared with other factors that have a larger impact on fuel economy,” the department wrote.

Saville said ethanol-blended fuel has the benefit of a high octane rating. “Adding ethanol to gasoline blendstock increases the octane rating of the fuel and improves combustion efficiency,” he said.

Those fuels can improve performance and fuel economy in certain engines.

“This is because the higher efficiency associated with ethanol as a fuel in a high-compression engine outweighs the lower energy density of ethanol,” Saville said.

This report by The Canadian Press was first published April 23, 2026.

Marissa Birnie, The Canadian Press