For years now, the aviation fuel discussion has mostly centered on one question: How do we get the lead out?
And that makes sense.
But maybe there is another question worth asking.
How do we reduce lead emissions while still burning 100LL that many aircraft engines were designed to use?
That is what caught my attention in a presentation at EAA AirVenture Oshkosh 2026 by Patrick Ealy, a master’s thesis candidate at the University of North Dakota. Ealy’s research does not argue that lead is harmless. Instead, it asks whether the issue — lead — is being framed too narrowly.
As Ealy put it, “The best way to reduce emissions is to reduce your fuel burn — how much of the stuff you are using.”
That is a practical place to start.
Ealy’s proposal has three parts.
First, install high-energy, variable-timing electronic ignition systems where practical. Burn less fuel and less lead goes into the atmosphere. The presentation highlighted early observations showing “20% to 25% savings,” adding that the technology “is available in the certified world.”
Second, move toward 100VLL, a very-low-lead version of avgas. Ealy framed this as “a stepping stone” and that phrase matters. Too often, the fuel conversation becomes all or nothing — either aviation gets the lead completely out or no progress counts. That seems like a poor way to solve a practical problem.
Ealy asked, “How many fewer tons of lead would be in the air, how much lower would the lead level be in the blood of our children, if we took a sensible approach and adopted technology as it was available?”
That’s a good question. It deserves an answer.
The third part is the one that really sticks with me: Capture lead before it leaves the airplane.
This concept relies on a lead-collecting anode in the exhaust stream. In simple terms, instead of focusing only on what goes into the fuel tank, Ealy’s idea asks what might be done about what comes out of the exhaust pipe.
“I believe we can sequester lead from the emissions and actually further reduce it significantly,” Ealy noted. “We can actually sequester it, hold it on the aircraft, and wipe out this anode at oil change periods so it’s no longer being emitted.”
That’s an interesting idea.
And that’s where it exists: An idea.
It would need engineering, testing, certification, maintenance procedures, cost analysis, and a clear answer for handling the captured lead. It would also need to prove it does not create new safety risks or maintenance headaches.
But aviation has solved hard problems before.
What I appreciate is how Ealy is reframing the topic. Much of the public discussion treats the continued use of 100LL as a moral failure. Ealy’s proposal treats it as an emissions challenge.
Aircraft owners are not refusing unleaded fuel because they enjoy lead. They want fuel that works in the airplanes they own, at the airports they use, in the conditions they fly. They want safety, availability, affordability, and trust.
Those are not unreasonable wants.
Maybe the lead-capturing exhaust filter is not the answer. Then again, maybe it is.
Regardless, it is the kind of question general aviation should be willing to ask.
I think this is a very smart idea. It would be great to use mogas in our Cessna 150 – it is certified BUT ethanol free mogas is almost impossible to find in California especially on the coast where we live. Our O-200 would be quite happy on lead free 91 octane. How to obtain the fuel is the problem.
The suggestion that all 100LL be replaced by 100VLL was explored and recommended in a 2021 report* by an expert panel of the National Academies Transportation Research Board (TRB). It found that since, by definition, every 100LL aircraft would automatically be satisfied by 100VLL (since its specifications fall entirely within those of 100LL), completely changing to 100VLL would reduce lead emissions by 19.6% [Chapter 5, page 101]. Combining substitution of 100VLL for 100LL together with use of UL94 unleaded avgas by the fraction of the fleet that can use it without modification (other than STC placards) would reduce overall aviation lead emissions by 40%.
The only reported issue with this recommendation was that some smaller avgas refineries might have difficulty meeting the 100VLL specifications.
*Options for Reducing Lead Emissions from Piston-Engine Aircraft, TRB Special Report #336, National Academies Press, 2021.
Innospec the only company that still produces tetraethyl lead has announced that it will stop production in 2030.
I fly my RV9A with mogas as much as I can. With 2600hrs on my O-320 in 20 years I still have good compression numbers and go through I qt of oil in 15 hrs. My only issue with mogas is inadvertently using winter blend on a hot spring day.
According to the Lycoming Member of EAGLE, presentation at AirVenture 2026, Innospec does NOT say they will stop in 2030. They say they will work with the EAGLE Program for a good transition away from TEL, no date to end.
Also, Innospec is often said to be the only producer of TEL. Not exactly correct, there are at least one producers of TEL in China. Not that we need or want Chinese made TEL.
I just ask if we can learn anything from the experience of the world. I know this may come as a shock but there is a whole lot of bright people and operations apart from America out there and why don’t we at least consider their experience.
Totally agree on every level.
A very interesting idea! Fixing the byproduct and not the input might just turn out to be the simplest solution.
Here’s some “gee whiz” info for my fellow West Coast GAN commenters.
This info is taken from the 2021 Reid-Hillview Airport (RHV) Lead Study. It’s 1 of 3 comprehensive studies on the effects of lead on children living IVO of airports. (The other two are the 2017 Michigan Airport Lead Study, and 2011 North Carolina Airport Lead Study. I’ll attach a link to a short summary of all three):
“More than one-third of the top 100 lead polluting U.S. airports are located on the West Coast.
Over 20% are in California.
– Of the 960 airports in California, 22 are included on this list. RHV ranks 34th.
– Nine California airports emit more lead annually than RHV does. The number in parenthesis refers to their ranking: Long Beach-Daugherty Field (2), Van Nuys (7), Montgomery Field (11), Gillespie Field(13), John Wayne (16), Palo Alto Airport of Santa Clara County (19), Chino (21) Livermore Municipal (28).
Nine of the 552 lead polluting airports in Washington State made the top 100 list.
– Auburn (22), Ephrata Field (32) and Boeing Field (33) emit more lead than RHV does.
– Harvey Field, Crest Airpark, Bremerton National, Paine Field, Renton Municipal, and Pierce County (Thun Field) are also among the top 100.
Among Oregon’s 420 lead emitting airports, 3 are among the top 100 lead polluting airports.
– Hillsboro Airport, the largest facility source of airborne lead by pollution in the state, ranks 8th.
– Bend Municipal and Troutdale are also among the top 100 lead emitting airports nationwide.
Other states heavily impacted by airport lead pollution include Arizona, Colorado, Florida.”
https://www.oregonaviationwatch.org/docs/AvgasBanSupport/AvgasBanSupportLetter-LeadStudies.pdf
And, if you look at the EPA lead monitoring at Reid Hillview for 2021 at the runup area, the measured value was 0.076 uG, vs an EPA limit of 0.15….so no hazard there !!
https://www.epa.gov/outdoor-air-quality-data/monitor-values-report
Great conversation going here! Personally, I’d like my plane to be able to use Mogas simply because it is an alternative that’s in ready supply which will reduce my fuel costs.
That said, hanging around the airport I hear stories of unleaded fuel melting gaskets in piston engines and causing other problems with the fuel systems but I have heard suspiciously little from the likes of Lycoming & Continental, and who should know better than them about the effects of running unleaded fuel in their engines then they do?
Instead Lycoming, and to a lesser degree Continental, seem to be more interested in taking issue with the way the G100UL mixture was approved rather than actively engaging with the testing and their customers, meanwhile Rotax continues to eat away at their marketshare in the sub 160HP range… Sounds strikingly similar to how the US automakers in the 70’s & 80’s responded to Japanese cars. I guess history does repeat itself…
No idea if he is right or wrong. But he said stuff others should have been at least investigating over the years. There are several reasons to reduce or eliminate TEL. Whatever change does or does not need to happen, let it be with a CLEAR and TRUTHFUL evidence.
” how much lower would the lead level be in the blood of our children ”
Well first you would have to find out how much is there now. But the jab was safe and effective because The Science was followed … all the way the fifth.
As far as know, it was never determined how many angels can dance on the tip of a needle.
One question. Have there been any studies of children’s blood levels of lead in areas far removed from the airport environs? I suspect that this whole “we have to do something NOW” panic would subside or disappear if it was shown that the vast majority of children not living near the airports had little to to no measurable lead in their blood. The solution then would be to ban housing within a certain distance from the airports. I have no sympathy forepeople who move close then complain about the noise. Far too many GA airports have been lost to the whiners.
I have reduced the fuel use by 20% in my Cessna 175B by replacing the wing tips with Hoerner tips, and having flap gap seals, reducing the tip vortex drag.
The POH list 8.8 gph at 2,500 ft and 2,800 rpm [ GO-300]. I now use 6.8 GPH.
Also, the stall speed dropped by 10 mph to 50 mph clean and 40 mph with 30 degrees flaps.
So, drag reduction is more effective than any engine mods in reducing lead emissions.
An electrostatic precipitator can remove the lead particles, but would be very large and requires a high voltage unit to power it.
I’ve been in the automotive business my whole life. In our industry, we have seen changes in the way cars are designed to control emissions. I read an article once they stated that over a 10 year vehicles life the amount of emissions saved is less than the amount of harmful emissions put into the atmosphere by pumping one tank full of gas true or false. I don’t know I’m not a scientist. But these are the questions we should be asking. Cost to the consumer, how much is it really gonna change “ saving of the Earth”, and is it just a profit thing for the go green Lords.
From firsthand experience and from harvesting experience data from other users of modern aircraft ignition systems, the fuel savings typically are on the order of 10%, not 20-25% as quoted by this masters student. Good research starts with getting good data. In this instance I believe the individual involved has cherry picked the data most favorable to his thesis defense.
Notwithstanding the above, the idea of using less leaded fuel is a valid one. By far the easiest method of achieving this goal is to allow those of us with engines capable of running 91 octane mogas to have access to this fuel without oxygenates (ethanol) added.
Again, from direct personal experience (I’ve been running 91 mogas for about 20 years in my personal aircraft fleet), this solution is the lowest hanging fruit and it brings many benefits including the removal of lead from other aspects of the aircraft lifecycle, including from the engine oil we touch and the spark plugs and exhaust systems which cause human exposure during maintenance.
Why is it that our governments (plural, across municipal, state, provincial and national borders) cannot tolerate the idea of alcohol-free fuel? In the area where I live it has been confirmed that ethanol is added to gasoline at the point where the fuel is being loaded into the tanker truck, not at the oil refinery at the upstream end of the supply pipeline. With this being the case, it should be easy to obtain and stock booze-free gas at an airport. Why is it not? This question is perhaps THE most salient question to be asked in the aircraft fuel debate, yet nobody seems to have the political guts to ask. This is very telling. Politics is fueled by money… Follow the money.
In support of Mr. Ealy’s thesis I will add that, by burning 91 octane mogas for the past two decades, I have intentionally, and with great operational success, refrained from burning several thousand gallons of leaded fuels. Others could do likewise, if only we could find the political will to mandate the limited availability of alcohol-free 91 octane fuel.
Many countries use MBTE
Does not Decalin RU help for the third part here ?
note…Decalin RunUp is not approved for use in the engines of certified aircraft .
However Alcor TCP is approved.
I’ve used it for 2 years now and it does a great job of removing the existing lead from the valve guides and cylinders.
Excellent point, Ben. I’m glad someone is thinking outside the box and exploring all options. As the owner of an engine that requires 100 octane and seeing little chance that a new unleaded fuel will meet that requirement and be safe for fuel system components, I would welcome an intermediate option.
A solution in search of a problem. Lead from general aviation fuel has no direct correlation to lead in the bloodstream. In fact; the PPM is de minimus in every study.
Further, RTECS (Registry of Toxic Effects Chemicals Substances) indicates humans can be exposed to .05mg/m3. Hardly zero and MUCH higher than any lead concentrations in a sky from a 4 cyl engine.
RTECS has this allowance for all routes of exposure including blood, airborne and ingestion.
In all things; its an environmental whacko thought process to eliminate what they deem is (queue the hand wringing)…. for the children. Whose live spans have never been longer.
Further, looking at the basis of the study; lead in kids. Much more incidence is centered on socio economic groups… Typically, property around a muni airport will be industrial mixed with some very inexpensive homes. Typically renters and more often minorities. The study sited supports this… .However, still not to the levels of causing long term detrimental health effects..
Ironically, the welfare system and more specifically food stamps, may also be a contributing factor to lead in children. Rarely do the poor use food stamps for high iron or high calcium based products which will resist lead being bound in tissue. A poor low iron diet is a contributing factor to long term storage of lead in the body…
“RESULTS. A significant independent relationship with the community case identification rate of lead poisoning was found for seven variables: median per capita income, percentage of housing built before 1950, percentage of the population who were Black, percentage of children screened, and a “poverty index.” Rates of iron deficiency and percentage of Hispanics were not associated with the case identification rate of lead poisoning. CONCLUSIONS. Massachusetts communities’ incidence of lead poisoning is correlated with sociodemographic and housing characteristics.”.
All this to say; General Aviation and lead in the fuel is a ruse but until there is a viable option; use 91 non ethanol and add in a lead additive. Don’t risk a $60k engine over the epa rule…
Almost like a Catalytic converter in a car..I personally can see this happening
Good ideas but there is another far simpler one – use ethanol-free, lead-free automotive fuel, aka Mogas. It could power at least 70% of all legacy piston aircraft and most of the latest generation powered by Rotax and similar engines. Rotax is the largest producer of piston aircraft engines by far. Mogas is available at most European GA airports, but not in America, despite our being the largest producer of fossil fuels.
I agree with Kent.
Make ethanol-free mogas more widely available,
and make that e-zero mogas available at more airports.