Lead is a known health hazard in brain development of children. The United States began doing away with leaded auto gasoline in the 1970s. The Clean Air Act of 1970 phased out leaded gasoline but there were also efforts to rid paint, plumbing and food cans of lead. However, there is one fuel that continues to use lead. Most of the aging fleet of general aviation aircraft use avgas that is 100 octane low lead or what’s called 100LL.
There are roughly 170,000 piston-engine general aviation aircraft with an average age of 50-years old. Most are flown infrequently. Indeed, the engines tend to wear out early from lack of use.
Pilots have worried for years about when the government will finally crack down on lead in aviation fuel and how much it’s going to cost them. That time has apparently come. I ran across a report by a Colorado State University professor who studies “health and human capital costs of environmental externalities.” The following are his findings:
“Across an ensemble of tests, we find consistent evidence that the blood lead levels of children residing near the airport are pushed upward by the deposition of leaded aviation gasoline,” said study author Sammy Zahran, associate chair of economics at Colorado State University in Fort Collins.
“This indicates we should support policy efforts to limit aviation lead emissions to safeguard the welfare of at-risk children,” Zahran said.
When analyzing the blood lead levels of children under the age of 6 from 2011 to 2020, the researchers discovered that the closer a child lived to the Reid-Hillview Airport in Santa Clara County, Calif., the more likely that child had a blood lead level that exceeded California’s safety threshold. That safety threshold is 4.5 micrograms per deciliter.
Blood lead levels were much higher when children lived East — or downwind — of the airport. Blood lead levels also increased with piston-engine aircraft traffic and quantities of leaded aviation gasoline sold at the airport.
California is especially unfriendly to general aviation. Apparently, Santa Clara County funded the study and has since banned sales of 100LL at the two county airports. Most airplanes cannot run on motor vehicle fuel due to the low octane rating. Also, airplane carburetors and fuel injectors are not designed to withstand the ethanol in motor vehicle fuel. Using auto fuel would also be illegal in most cases.
The FAA approved a replacement fuel in July 2021 developed by General Aviation Modifications Inc. (GAMI). Experts estimate G100UL will likely cost up to $1 a gallon more than 100LL. A quick study of avgas prices where I live range from $4.60 a gallon for self-service at an airport 65 miles from Dallas to $8.07 a gallon for full service at an airport serviced by airlines. In the future add $1 to those figures.
Paradoxically, FAA regulations require a supplemental type certificate (STC) to deviate from aircraft manufacturers’ specifications that all require 100LL. That means pilots will have to pay GAMI hundreds of dollars for a sticker to put next to their fuel tank ports and airframe logbooks saying they have permission to use the new fuel. One pilot said the STC for his twin-engine Beechcraft will cost $1,500, even though the FAA will ban the old 100LL fuel at some point. Industry observers believe the EPA and environmentalists will push to quickly get rid of 100LL as soon as possible. In January 2022 the EPA announced it had begun officially evaluating whether lead emissions from piston engine aircraft are a health hazard.
More about aviation fuel: The Catch-22 of unleaded avgas — General Aviation News