Aviation enthusiasts, local officials and community members gathered Friday at Boulder Municipal Airport to celebrate the arrival of unleaded aviation fuel, marking another step in the airport’s transition away from leaded gasoline.

Boulder is the third airport in Colorado to offer UL94, an unleaded aviation fuel compatible with an estimated 70% of piston-engine aircraft. City officials hope the new fuel will reduce airborne lead emissions while encouraging a broader transition as more aircraft become compatible with unleaded alternatives.

Read: Boulder Airport begins transition away from toxic leaded fuel

UL94 can be used by an estimated 70% of piston-engine aircraft. At Boulder Municipal Airport, that includes about 100 fixed-wing aircraft. Of the 187 aircraft based at the airport, many remain unable to use the fuel until newer formulations become available. The fuel is stored in a leased skid-mounted tank that provides full-service fueling and is available to both Boulder-based pilots and visiting aircraft.

A state grant is subsidizing the cost of UL94 so it matches the price of leaded aviation fuel, encouraging pilots to make the switch. Boulder Airport is also offering rent credits for aircraft certified to use unleaded fuel.

โ€œThe progress in the last few months has been very swift,โ€ said Assistant City Manager Pam Davis said, referring both to the pace of the project and advances by manufacturer Swift Fuels. โ€œThis will reduce airborne lead emissions, protecting the lives of those who work here and live around the airport.โ€ 

Andrew McKenna, president of the airport’s fixed-base operator, refuels a Soaring Society of Boulder plane with unleaded aviation fuel on July 10, 2026. Credit: Por Jaijongkit

Andrew McKenna, president of the airport’s fixed-base operator, Journeys Aviation, said he expects an unleaded fuel compatible with all piston-engine aircraft to become available by the end of the year.

โ€œUnfortunately, these things take time but itโ€™s coming,โ€ he said.

McKenna said he also hopes to make airport operations more sustainable by eventually introducing battery-powered aircraft and expanding electric infrastructure.

David Ulane, director of aeronautics for the Colorado Department of Transportation, credited the collaboration among the city, the airport, Journeys Aviation and the state for bringing the fuel to Boulder. He said he expects the price of unleaded fuel to fall as adoption increases.

Community members and local officials gather July 10, 2026, to celebrate the launch of unleaded aviation fuel at Boulder Municipal Airport. Credit: Por Jaijongkit

After remarks from speakers, officials held a ceremonial ribbon-cutting. McKenna then fueled one of Journeys Aviation’s aircraft and a tow plane from the Soaring Society of Boulder.

Several local officials attended, including state Sen. Judy Amabile, Boulder County Commissioner Ashley Stolzmann, and Boulder City Councilmembers Matt Benjamin and Rob Kaplan.

Airport staff said the first sales of the new fuel occurred later that morning. Journeys Aviation and the Soaring Society of Boulder have both committed to using UL94, and Boulder Airport Manager Eric Vences said those aircraft account for roughly half of operations at the airport.

Por Jaijongkit covers climate and environmental issues for Boulder Reporting Lab and was a 2024 Summer Community Reporting Fellow. She recently graduated from CU Boulder with a master's degree in journalism and is interested in writing about the environment and exploring local stories. When not working on some form of writing, Por is either looking for Thai food or petting a cat.

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2 Comments

  1. It’s about time!!! I live under what should NOT be their flight path, by Centennial Middle School, but my weekends are a miserable as everyone elses! Now, perhaps unleaded loud misery. Jane

  2. The EPA and the U.S. Department of Transportation officially ended leaded gas at stations across the country in 1996. Mr. McKenna said that “Unfortunately, these things take time….” Do they, though? When we have not pumped leaded fuel into cars for at least 30 years. Should they really take this much time to remove a known health-hazard from transportation use? We’ve known about anthropogenic climate change since at least the 1980s and, today, parts of Colorado, Canada, and Europe are on fire. It’s a matter of priorities and, as a society, we haven’t gotten ours straightened out just yet. And that makes us culpable.

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