The Rocky Mountain Metropolitan Airport in Broomfield is angling to be the first airport in the state to fully eliminate leaded aviation fuel by 2027 — three years ahead of a Federal Aviation Administration deadline.

The third busiest airport in the state, Rocky Mountain Metropolitan Airport operates with more than 400 aircraft and 50 businesses.

Aviation gas type 100-octane low-lead remains the last major source of motor fuel containing lead. It is used in piston-engine aircraft to prevent damage due to the high stresses experienced by high-performance aircraft engines. The FAA has set a 2030 deadline to stop using the leaded fuel, leaving general aviation airports figuring out how to make the transition.

“Our team’s commitment to innovative solutions and community collaboration is why the airport’s full transition will be well in advance of the FAA deadline,” airport Director Paul Anslow said. “The aviation industry is working to scale production of 100UL for the larger market, and we feel confident that availability will rapidly increase while the price decreases. Our goal is to be the first airport in the state that fully transitions to unleaded fuel.”

Development of lead-free aviation gas has been in the works for many years. In 2022, the FAA approved 100UL unleaded fuel — which is suitable for all piston aircraft engines. The fuel is not widely available now. Aviation 100LL fuel contains 2.12 grams of lead per gallon.

The U.S. Environmental Protection Agency published a notice of a proposed endangerment finding that lead emissions from aircraft may endanger public health and welfare in the Federal Register on April 28, 2010.

“The human exposure pathways for lead emitted into air include inhalation of ambient air or ingestion of food, water or other materials, including dust and soil, that have been contaminated through a pathway involving lead deposition from ambient air,” the notice said.

The proposed rulemaking process was halted as the FAA, EPA and stakeholders worked collaboratively to come up with a solution. But environmental advocacy groups, such as Earthjustice, are highly critical of the delay in completing the rulemaking.

“We’ve known for decades that lead exposure is responsible for the death of nearly half a million adults annually from cardiovascular disease — and causes irreversible damage to children. EPA must finalize its endangerment finding as soon as possible, and work with the Federal Aviation Administration to quickly phase out leaded avgas,” Eve Gartner, Earthjustice’s managing attorney, said on the organization’s web page. “Banning leaded avgas cannot wait. Every day that goes by without a ban means communities across the country, including hundreds of thousands of children, are breathing lead causing lifelong harm.”

Leaded motor fuel was banned for use in automobiles in 1975 and fully phased out by 1996. Leaded gasoline is still allowed for off-road use in racing cars, farm equipment, and marine engines.

The FAA forecast for consumption of leaded aviation fuel in the U.S. ranges from 185 million gallons in 2026 to 179 million gallons in 2041, a decrease of 3% in that period. Aviation gasoline emissions, comprise 470 tons of total national lead emissions of 670 tons, the EPA said. 

Rocky Mountain Metropolitan Airport, founded in 1960 and owned and operated by Jefferson County, is a general reliever for Denver International Airport. A major economic driver in the region, the airport’s yearly economic impact is $731 million, according to a 2020 economic report.