The Boulder Municipal Airport will offer unleaded fuel starting this week in an effort to address long-standing concerns from the public.
The unleaded fuel will be offered by Journeys Aviation, a flight school that is the airport’s fixed-base operator. A fixed-base operator is a commercial business that acts as an airport’s designated source for services such as fueling and maintenance. The city does not directly purchase fuel.
Boulder estimates that about 100 of the 139 fixed-wing aircraft housed at the airport will be eligible to use the unleaded fuel, which is UL94 aviation gas from the Indiana-based Swift Fuels. The city will host a small celebration and a ceremonial unleaded fueling of an aircraft at 9 a.m. Friday at the airport.
Boulder is providing incentives for airport operators to transition to unleaded fuel. It will also offer rent credits to help airport tenants pay to have their aircraft certified for unleaded fuel. Doing so is a federal requirement for any aircraft using UL94. The city is using $63,000 from a Colorado Department of Transportation grant to fund these incentives, and $7,000 from the airport fund. State grants don’t come with an expectation that the airport must remain open indefinitely, unlike the federal grants that have clouded the long-term future of the airport.
The development is a step toward addressing a major concern over the environmental and public health detriments of leaded aviation fuel that critics of the airport have rallied around.
“For many years, it has been our goal to make aviation in Boulder more environmentally sustainable. Providing unleaded fuel gives UL94-certified aircraft a dependable option while making a big step forward with the core values of the airport, city and community,” Boulder Airport Manager Eric Vences said in a Monday news release. “Several operators have already committed to the switch.”
Leaded fuel has long been a source of concern for environmental and public health advocates. In 2023, after years of outside research, the Environmental Protection Agency issued a final endangerment determination that leaded aviation fuel causes or contributes to air pollution and has harmful impacts on children.
A 2011 study published in the peer-reviewed journal Environmental Health Perspectives found that children living near airports that had aircraft using leaded fuel had higher levels of lead in their blood than those who didn’t.
Lead exposure can impact a child’s brain and nervous system, therefore having a negative impact on their development, intelligence and performance in school, according to the Centers for Disease Control and Prevention.
“Within the next year, we anticipate bringing Swift’s 100R unleaded avgas to Boulder, a fuel that is expected to be approved for all 100% of the piston-powered fleet of aircraft,” Vences said in the news release.
Low-leaded fuel will still be offered at the airport until 2030, the year that the Federal Aviation Administration is targeting to transition to unleaded fuel.
“The FAA requires airports to maintain the low-leaded option until 2030 or until a fleetwide status is granted to an unleaded fuel type,” the city said in a follow-up email to the Daily Camera. The Federal Aviation Administration has a mandated goal for piston-engine aircraft to transition to unleaded fuel by 2030.
The city does not anticipate that this development will impact airport operations. Passerby training flights typically don’t refuel at the airport because they’re based at other airports, the city said.
Smaller, older piston-engine aircraft tend to use leaded fuel. Larger commercial airliners use jet fuel that does not contain leaded fuel.
Boulder Municipal is the latest Front Range airport to make this change. Broomfield’s Rocky Mountain Metropolitan Airport began offering unleaded fuel in February, and Centennial Airport in Arapahoe County does so.