Understanding the Transition to Unleaded Aviation Gasoline: A Primer (2026)
Chapter: What Are Governments and Agencies Doing to Support the Transition to Unleaded Aviation Gasoline?
The U.S. Environmental Protection Agency (EPA), with respect to lead emissions from aircraft, recently stated that:
“Lead emissions from aircraft are an important and urgent public health issue. Lead exposure can have harmful effects on cognitive function, including reduced IQ, decreased academic performance, as well as increased risk for additional health concerns. There is no evidence of a threshold below which there are no harmful effects on cognition from lead exposure” (EPA 2023).
Considering the EPA’s statement, there has been an increasing level of interest in reducing both emissions and public exposure to lead resulting from aviation gasoline combustion. As discussed later, these ongoing efforts include changes in airport operations to reduce exposure to lead, the development and deployment of unleaded aviation gasolines, and recent federal government regulatory programs aimed at achieving a complete phaseout of the use of leaded aviation gasoline in the United States by the end of 2030.
Given the environmental concerns regarding lead emissions from aircraft, the commercial availability of unleaded aviation gasoline suitable for safe use in many types of aircraft, and current and upcoming local, state, and federal government regulations driving the change, a shift is already underway. Some airports have begun providing unleaded aviation gasoline while continuing to comply with statutory requirements to supply leaded aviation gasoline until a suitable alternative is available for all aircraft that at the time of this publication rely on 100-octane low-lead (100LL) (see the section that follows for additional information).
What Are Governments and Agencies Doing to Support the Transition to Unleaded Aviation Gasoline?
In October 2023, the EPA published its determination that “lead emissions from aircraft engines that operate on leaded fuel cause or contribute to air pollution which may reasonably be anticipated to endanger public health and welfare” (EPA 2023).
As a result of this finding, the EPA is subject, under the Clean Air Act, to propose and issue regulatory standards for lead emissions from aircraft engines that use gasoline. Under its own authorities, the Federal Aviation Administration (FAA) now has an obligation to develop standards that address the composition or chemical or physical properties of aircraft fuels or fuel additives to control or eliminate aircraft lead emissions. In other words, this finding marks the beginning of a multi-year regulatory process expected to achieve the complete phaseout of lead from aviation gasoline by the end of 2030.
By law, under the Clean Air Act, the EPA and FAA must consult with each other on these rulemaking requirements to ensure they are developed in a manner that does not adversely impact aviation safety. Although both agencies have reported working collaboratively on these standards, there have been no agency announcements to date regarding their scope or the timing of the pending regulatory process. A white paper that addresses the implications of the EPA endangerment finding in more detail is available on the Eliminate Aviation Gasoline Lead Emissions (EAGLE) initiative website (EAGLE 2023). As discussed in more detail later, EAGLE is a government-industry partnership formed to coordinate efforts toward a safe and timely transition to unleaded aviation fuel.
