Gas is about to get more expensive in Denver thanks to northern Colorado’s bad air. But by how much?

Severe ozone pollution in metro Denver and the northern Front Range will lead to more expensive gas prices this summer as stations switch to a specialized fuel blend that will burn cleaner and release fewer toxic emissions into Colorado’s air.

But exactly how much prices will increase remains a source of debate, with estimates ranging from less than a nickel to 60 cents per gallon — which would push gas above $4 a gallon for the first time in two years.

Gas stations in a nine-county region must sell reformulated gasoline from June 1 to Sept. 15 as part of a federal Clean Air Act requirement for areas designated as being in “severe non-attainment” of National Ambient Air Quality Standards.

Denver and the northern Front Range received that designation from the Environmental Protection Agency in 2022, and the region was given two years to prepare for the mandate.

The requirement to use reformulated gasoline comes at the beginning of the summer driving season, when gas prices typically spike because fuel is in higher demand as families hit the road for vacations.

Gov. Jared Polis and other political leaders unsuccessfully fought the requirement, saying the cost for consumers outweighs any environmental benefits. They also fear Adams County, which already suffers from poor air quality, will be burdened by more pollution as petroleum companies build extra storage tanks to hold the reformulated gas and as more tanker trucks drive into the area to deliver it.

When northern Colorado was listed as a severe non-attainment zone in 2022, gasoline suppliers started preparing to manufacture and store the reformulated gas. Suncor Energy, which operates Colorado’s only oil refinery in Commerce City, told The Denver Post in an email that it spent $45 million at its facility so it could create the special blend.

Reformulated gas burns cleaner and is more efficient than the gasoline motorists typically pour into their cars’ tanks. Exhaust from cars and trucks running on reformulated gas releases fewer chemicals that combine on hot summer days to create ground-level ozone pollution, which exacerbates global warming and causes respiratory problems in humans.

The EPA started requiring reformulated gas in severe non-attainment zones in 1990 to reduce summer smog, but it’s not mandated year-round because ground-level ozone isn’t as big of a problem when the weather cools. Seventeen states, including California, and Washington, D.C., sell the gasoline, according to the EPA.

The EPA estimates that 210 tons of volatile organic compounds and 50 tons of nitrogen oxides will be eliminated by using reformulated gasoline in Colorado over the summer. At the same time, the EPA’s economic analysis predicted gas prices will only increase by three to five cents per gallon, said Richard Mylott, an agency spokesman.

Colorado is behind in meeting two national air quality standards, and every step moves the state closer to compliance, he said.

“That means every ton reduced and every part per billion in air quality improved matters,” Mylott said. “Reformulated gasoline is one of those measures. Every part per billion has a health consequence and we need to remember that.”

“Nobody wants to sell reformulated gas”

Representatives from the petroleum industry say reformulated gas will cost more because it is more expensive to make since it is more refined than conventional gasoline and contains oxygenate to improve combustion.

The Suncor refinery provides about one-third of the gasoline used in Colorado. Other petroleum companies will send reformulated gas to the region via pipelines, mostly from Texas.

Because those companies are spending money to make reformulated gas and move it to Colorado, they will increase the price of gas for retailers. So gas stations will raise prices at their pumps.

Studies in California have shown reformulated gas causes the cost of a gallon of gas to rise by 35 cents, said Grier Bailey, executive director of the Colorado Wyoming Petroleum Marketers Association, which represents retailers and trucking companies.

“The reality is that going to a more stringent fuel blend makes the logistics and the supply situation much more delicate,” Bailey said.

Most gas stations will delay selling reformulated gas as long as possible, but it will start being delivered later this week.

“Nobody wants to sell reformulated gas because it’s way more expensive so they’re holding off until they have to,” he said.

Polis in April sent a letter to the EPA to ask for a waiver on the reformulated gas requirement. U.S. Rep. Yadira Caraveo, D-Adams County, also sent a letter in April to President Joe Biden to request a waiver.

The governor’s office commissioned an independent study on reformulated gas that determined prices could increase as much as 60 cents per gallon in the nine-county region, according to the letter.

The governor also argued that Colorado has taken more significant steps to clean its air, including a push for more electric vehicles on the roads and incentives for people to use public transportation in the summer, and that reformulated gas would do little to contribute to significant improvement.

“The bold actions Colorado has taken, and continues to take, to reduce emissions from the transportation sector and move away from the use of fossil fuels have negated any potential emissions or environmental benefit from the costly and harmful (reformulated gas) mandate,” the governor wrote.

Bailey also criticized the reformulated gas requirement as outdated, saying fuel efficiency in cars has improved over the past 30 years.

But the EPA said it would not grant the waiver because federal law does not give the agency that flexibility.

Instead, the EPA is holding the waiver open in case an emergency causes a fuel supply shortage, said Adrienne Sandoval, air program director for the agency’s Region 8. For now, a fuel supply shortage is not anticipated, but something catastrophic such as a hurricane along the Texas Gulf Coast could cause one, she said.

In that case, the EPA would be able to invoke the waiver within 24 hours, she said.

“Continued volatility at the pump”

The EPA maintains that reformulated gas can be manufactured, stored and transported in the same refineries, tanks, pipelines and trucks that handle regular gasoline. However, three petroleum companies  — Suncor, Magellan-Dupon and Holly Energy Partners — have cited the requirement in applications to expand their facilities in Adams County.