Despite the removal of poisonous lead from automotive fuel in the face of growing health problems, aviation fuel for small planes still use leaded gas extensively. In attempting to replace leaded aviation fuel with more human-safe alternatives that aren't as toxic, the Federal Aviation Administration has increasingly become an accidental roadblock to progress, according to Quartz.
The issue—which unfortunately hasn't seen much progress since our initial reporting—has returned to the forefront after a small airport, Reid-Hillview in Santa Clara County, California, banned refueling planes with leaded gas. While the FAA currently has a program for developing, testing, and certifying lead-free aviation fuel (known as Eliminate Aviation Gasoline Lead Emissions, or EAGLE), it also has tied federal funding to the availability of currently approved fuel. As a result, when Santa Clara County banned leaded gas, the FAA opened an investigation and threatened to pull $11 million in federal funding from the airport.
The Environmental Protection Agency currently, despite its long-standing ban on lead additives in terrestrial fuel, does not consider leaded aviation fuel a health threat. It initially opened an investigation in 2011 but was delayed under the previous presidential administration. The Biden administration announced a new focus on lead pollution mitigation last year, and the anonymous EPA official who spoke with Quartz expects to see officials declare it a health hazard formally sometime next year. The FAA has a target deadline of 2030—seven years after the expected announcement from the EPA—to actually replace all aviation fuel with unleaded variants, despite documented potential health risks to people living near small airports.
The FAA's testing process for new, unleaded aviation fuel is complicated, however, and so far the two major contenders in testing via the EAGLE program still contain an abundance of MMT, a compound with similar neurotoxic properties to lead. An unleaded fuel developed by the company GAMI has attempted to bypass the EAGLE program by getting type-certified for use in all aircraft, and has made it through every FAA test needed; however, the final signature for certification has been delayed for unknown reasons.
Unfortunately, until the fuel itself is fixed, there aren't many alternatives for most airplanes currently flying the skies. Lead additives in fuel act as an octane booster and help reduce the chance of engine knock, and most of the small planes still using it date back decades, even pre-dating the automobile leaded gasoline ban. Even if the FAA would allow certain localities to ban refueling with leaded gas (such as Santa Clara County), a large number of the planes flying would still need it; the detuning required to fly at lower octane levels would mean engines wouldn't have the power to even take off the ground.