Report Calls For Multi-Pathway Approach To Mitigating Aviation Lead


A new report published by the National Academies of Sciences, Engineering, and Medicine Transportation Research Board says multiple mitigation strategies are necessary to reduce lead emissions from piston aircraft. The study, “Options for Reducing Lead Emissions from Piston-Engine Aircraft,” was conducted by a ten-person committee in response to a congressional request laid out in the FAA Reauthorization Act of 2018. The committee’s stated goals were to assess existing non-leaded fuel alternatives to aviation gasoline, ambient lead concentrations at and around GA airports and mitigation measures to reduce those ambient lead concentrations.

Noting that “lead exposure can result in an array of negative health effects in humans,” the committee’s recommendations for near-term mitigation efforts included having the FAA establish a partnership with GA organizations to create an ongoing education, training and awareness campaign on avgas lead exposure. In addition, it asked the agency to update its guidance on runup area placement and called for an exploration of policy options for motivating the production and supply of 100VLL (very low lead) and encouraging greater use of available unleaded avgas options “by the portion of the piston-engine fleet that can safely use it.” The committee also recommended that work continue on finding a universal unleaded replacement fuel for 100LL via the Piston Aviation Fuels Initiative (PAFI) or an alternate evaluation process, but acknowledged that a universal replacement fuel could prove difficult to develop.

“Without leaded avgas, tens of thousands of piston-engine aircraft, used for a wide range of beneficial GA purposes, could not be safely flown,” the committee said in its report. “Decades of research on octane-enhancing additives have failed to find an alternative to lead that performs in an operationally safe manner for all GA aircraft in use today. Hence, eliminating lead from avgas is a highly desirable public health goal, but one that has been difficult to achieve.”

For longer-term mitigation strategies, the committee suggested that all newly certified gasoline-powered aircraft be approved to operate using at least one ASTM-specified unleaded fuel after a set date. It also called for initiatives aimed at promoting the development, testing and certification of lead-free propulsion systems for GA aircraft along with the associated airport refueling and recharging infrastructure.

The complete report can be downloaded for free from the Transportation Research Board’s website at

Kate O'Connor
Kate O’Connor works as AVweb's Editor-in-Chief. She is a private pilot, certificated aircraft dispatcher, and graduate of Embry-Riddle Aeronautical University.

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    • That is fine for low compression and smaller engines but try running anything over an 0360 or fuel injected and you will have all kinds of problems not to mention finding it without ethanol in it which will destroy your engine.

      • I run a C182 with an O470R/230 hp. When 80/87 disappeared, I switched to 100LL. It didn’t take long to find 100LL is bad for the engine in nearly every way. I got the Peterson STC and ran 87 octane leaded mogas until it was gone because of fear of going completely lead free. At the time the 80/87 spec contained a Pb level but only because it allowed pipeline washout from lines that also carried 100/130 and 100LL. After leaded mogas was completely phased out, I switched to ETOH free mogas and ran more than 1000 hours past TBO with no difficulty and spark plugs stayed clean. I suspect it will run just fine in a TSIO470 if given the opportunity. The higher compression O470 will still require the higher octane leaded fuel.

        Biggest problem today is finding ETOH free fuel, which is available in both of the states I fly in regularly, and finding mogas at airports as fewer are carrying it.

        • Art
          I agree. Until it disappeared my C182P ran only 80/87. I don’t know why it went away given the number of planes that used it.
          Why couldn’t one of the 4 pumps on my airport’s fuel island have 80/87?

          Ethanol free mogas is banned in my state.

          But then what does logic have to do with saving the planet?

        • The reason 80/87 went away is the reduction in total fuel used. I saw an article one time that had the figures that stated while less than 25% of the aircraft flown require 100 octane fuel since they are the really high horsepower aircraft (a lot of twins) they use in excess of 75% of the fuel. It was significantly less expensive to just go with one fuel. Most aircraft could be certified to fly with something existing but no one wants to pay for the testing. Getting an STC these days is ridiculously expensive. there is an AV web article from 2004 that talks about this called AvGas vs. AutoGas

  1. “For longer-term mitigation strategies, the committee suggested that all newly certified gasoline-powered aircraft be approved to operate using at least one ASTM-specified unleaded fuel after a set date.”
    Why didn’t they do that 30 years ago?
    Are we going to keep kicking this can down the road forever?

    • if you look at the GAMA annual report the total piston engine aircraft shipments for 2019 was 1,324 and in 2018 was 1,137. and that is worldwide. Kind of hard to justify the cost of the testing that the FAA would require for that few aircraft.

  2. Like many problems in this country today, there are opposing forces that need to work together. In this case, the aviation industry could easily come up with an engine that runs on a different fuel. However, it is not economical to do so because costly certification requirements which are overdone by the FAA in many cases. My favorite is the $350 USB plug in the dash of an aircraft but I’m still allowed to use a $10 cigarette lighter version because it’s not permanently installed.

    I’m not saying engines shouldn’t be thoroughly tested. They should. I’m simply saying that certifications and economics are completely out of balance when it comes to bringing new products and designs to the GA market.

  3. (Yawn). ANOTHER “report” from “National Academy of Sciences” “calling for a solution.” And just WHAT do their “calls” accomplish? Absolutely nothing.

    If these are really “scientists”–have THEM show us an alternative. They’ve been flogging this dead horse for 30 years and hundreds of millions of dollars–and produced NOTHING. Even the government (FAA) abandoned the chase for unleaded gas–finally recognizing it as being “unworkable.”

    This might be far-0ut–but consider–IT WOULD LIKELY HAVE BEEN CHEAPER FOR THE GOVERNMENT TO BUY UP EVERY “OFFENDING” ENGINE that to keep throwing money down this rat hole, with no discernible results. Give the money to the aircraft owners, who can then decide whether to scrap the airplane, OR MORE LIKELY, free enterprise will come up with an alternative engine that the aircraft owners can buy–using the money from the sale of their engines. It would also allow those orphaned airframes to be licensed Experimental. Once again, private enterprise will succeed when government fails–IF ONLY GOVERNMENT GETS OUT OF THE WAY.

    It solves the fuel issue once and for all. It gives us modern technology (no more magnetos). It saves fuel (better fuel specifics). If it runs on Mogas or Diesel, it eliminates a special fuel that is a problem for refiners and pipeline operators to implement and transport.

    IF this is the big problem that “the committee” says it is, the problem is solved–cheaper, and quicker.

  4. “lead exposure can result in an array of negative health effects in humans,”

    Since we are NOT seeing any deleterious health effects from the minuscule use of 100LL, I can only assume that this means that someone is about to receive a huge government grant.

  5. Given that this failure to “produce an alternative fuel” is cause by GOVERNMENT–perhaps we should have these same people conduct a survey on “why won’t pilots use Mogas, and what can we do to convince them to do so?”

    As an FBO, we installed a Mogas pump when it was first approved. We run all of our Warriors on it–both 150 and 160 hp models. In all of these years, and about 1000 hours a year, we have never had a fuel-related problem. This is in Minnesota–where temperature swings are among the highest in the U.S.–from 100 degrees down to 30 below. Not one engine has failed to make TBO–in fact, it has been 10,000 hours since we have changed a cylinder. Yet private pilots are still reluctant to use it–even at a savings of $1 a gallon. Just up the road, another FBO maintains and crews a fleet of aircraft (mostly older Cessna Cardinals) that use auto fuel. This fleet of over 25 aircraft regularly goes to 4000 to 5000 hours between overhauls on average–almost exclusively on auto gas (they get enough 100 octane to satisfy the STC when fueling away from home).

    Perhaps the difference is in the PRODUCT AND HANDLING. We get our Mogas from a local refinery, because we can get less than truckload delivery–assuring that the gas is “fresh.” Every load comes with a “birth certificate”–the composition of the gas, the actual octane, the Reid Vapor Pressure. The gas is hauled in dedicated aviation fuel trailers. It is stored underground (no condensation) in tanks with a floating suction. It is filtered prior to dispensing, and we have a filter alarm.

    I understand that your local gas station can’t make those assurances–but we treat the fuel exactly like we would 100 octane–would you want anything less? A number of years ago, I had a BT-13 with an R-985 fuel up on the way to the West Coast from Oshkosh–it was flown by an attorney. A couple of weeks later, we got a phone call–“I think I got some bad gas there–I had some engine problems–what are you going to do about it?” I told him “You picked the wrong guy to tell THAT FAIRY TALE TO!” and provided the documentation. We never heard back from him

    The question is–why don’t most pilots use auto gas? It’s LEGAL, and it’s SAFE, and it SAVES MONEY. We see people pull up to the pump–they have auto fuel STC stickers on the aircraft, but they burn 100 octane. When asked WHY?–they say “I’ve heard that stuff isn’t good for the engine.”

    As a subscriber to Aviation Consumer (and formerly to Light Plane Maintenance) as well as watching Avweb–we could cut down the consumption of 100 octane considerably by using aviation auto fuel–and MAYBE THE “CONCERNED SCIENTISTS” AND THE GOVERNMENT WOULD LEAVE US ALONE! (On reviewing that comment–NAH!!!)

    • Most don’t use auto fuel because it is a pain in the ass. With my F35 if it has alcohol in it it can damage $6000 worth of bladders plus installation and cause a need for an overhaul of my carburetor @$4000. The savings are not worth the trouble of carrying the fuel to the airport, finding a fuel that is alcohol free (80 miles away), the danger pouring large amounts of fuel from cans and potential damage. It sounds like it works well for you though. I flew for a glider operation and we used unleaded alcohol free automotive fuel from Southern States. It worked well. We had a tank set up with an electric pump on the field.

    • Jim,
      Kudos to you for providing it on field. I am fortunate that I have mogas on field nearby at each end and at my fuel stop. I don’t understand why those who can don’t use mogas. My experience with the O-470R is really clear. I bought the airplane with 250 SFREM when 80 was plentiful. Both I and the former owners used that strawberry colored gasoline (Pb @ 0.14 g/gal) from the day the engine was installed. When 80 went away, I got the STC because of the problems I was having with 100LL mainly with lower plugs fouling. My engine is cold blooded anyway (CHTs in the low 300s most of the time, so Pb fouling was huge. When I switched over to 87/Unleaded mogas ETOH free, I stopped having problems, stopped having to clean the brown lead bromide stains from the belly, and things just plain ran better. At 2800 hours (on the 1500 hr TBO engine) it finally needed an overhaul due to an increase in nickel and ferrous metal in the oil followed by low compression on #4 at 1270+ past TBO. I took it to my favorite engine builder for a new limit overhaul. The very first words out of his mouth were: You use mogas, I won’t touch it! I told him it needs a new cam and I was willing to spring for it (one lobe had spalled, an oil/lack of use issue more than a gasoline issue, well known for these engines), and agreed to spring for new cylinders, he took the job.

      He called me after the tear-down and asked me how I was flying the engine because it was the cleanest O470 he had ever taken apart. He still thought I shouldn’t be using mogas, but did a very sweet overhaul and insisted I run the airplane on 100LL for the first 50 hours and for break in. At the 100 hour I called him and told him it was perfect and I ran the last 50 on the mogas. He now uses mogas. At 2650 on the 1500 hour engine without a glitch flying 150-250 hrs/year. The only 100LL in the plane is on the road. And the spark plugs are still good. I do worry that mogas is getting harder to find both at the pump and at the airports.

  6. Has anyone really taken a look at the real impact of this fuel on the US? Or are we trying to get that last 0.05% that costs so dearly and has no affects on the health of the people? My plane will run on unleaded fuel fine. I wish they would provide the same fuel we get now without lead. I understand it is about 90+ octane.

    • See my post–ANY refinery can make it–you just have to find one that will. THIS is something that the aviation “alphabet organizations” could do very easily–publish a list of refineries that make it. EVEN BETTER–publishing this list on AvWeb and Aviation Consumer would not only be doing a service to pilots and readers, but would help in reducing the aviation lead content EVEN FURTHER–the goal of the very people that have been “studying the problem” for 30 years.

      It’s even available here in the “Socialist State of Minnesota”–where the government mandates EVERYTHING.

      One further possibility–some people object to the use of auto fuel because of the smell. The odor is put into the fuel AFTER refining–there is no reason for it other than to identify it as a “road fuel.” It COULD have the same smell as “avgas”–and could even have the red color of the old 80 octane (or any OTHER color specified.)

      In short, there is no reason NOT to!

  7. The entire existing GA piston engine fleet will never be able to run on lead free gas; but the real question is why bother as the damage done to human health is negligible. Just provide containers to dump drained fuel and do engine run-ups in safe areas in congested airports.

    • But most of that lead comes out the exhaust. Back before leaded fuel was banned for road cars, lead could be detected in roadside plants.

  8. “The committee also recommended that work continue on finding a universal unleaded replacement fuel for 100LL via the Piston Aviation Fuels Initiative (PAFI) or an alternate evaluation process…”

    The alternative approach to PAFI in finding an unleaded universal replacement for 100LL already exists. It is the STC process. It has been ongoing, with limited industry-government support, for longer than the UAT-ARC/PAFI process. When I served on the FAA’s UAT-ARC (predecessor to PAFI) I caught significant political heat for publishing an opinion that a dual-track process (both STC and PAFI) was needed and prudent. Upon review today, what I expressed 10-years ago is still true. Now, that PAFI has failed to discover a solution, the STC process is all the more important to the fleet and preserving aircraft utility and values.

    My understanding is that a the FAA has, beginning about 8 months ago, changed the personnel to support unleaded avgas projects, devoted more resources to supporting this approach, and that the progress toward the solution we all need is encouraging. The specific certification testing and results are not mine to divulge, but I will just say that I do not expect the future utility/value of my Piper Mirage (350HP turbocharged Lycoming engine) to be at risk.

    I am surprised that the National Academies of Sciences, Engineering, and Medicine Transportation Research Board did not know about, or did not report on encouraging progress in this area. The report seems a bit behind the curve IMO.

  9. My airplane prefers fuel that is ethanol and lead free. Maddeningly, mogas has ethanol in it, and avgas has lead in it. In some parts of the country you can get ethanol-free mogas, but in the northeast corridor and in California – i.e., places where very substantial portions of the population live – it’s either very rare (northeast) or nonexistent (southern California).

    I started flying in a C150, and we had to use anti-lead-fouling procedures to deal with the fact that its engine was designed on the assumption that we would soon be using lead-free fuel. The C150 was introduced 60 years ago. That means we have been anticipating the phase-out of lead for more than half the history of manned flight – and not only have we not gone that direction, we’ve done the reverse: we’ve dropped lead-free avgas! And so I’m changing the oil in my Rotax every 25 hours, because of the lead precipitating out in the oil.

    Sure, Rotax (and perhaps other engines) are okay with up to 10% ethanol in the fuel – in theory. In practice, we fill the tanks and let our airplanes sit for weeks between flights, sometimes. Or often. And the ethanol settles out. So what’s at the bottom of the tank isn’t 10% ethanol: it’s a much higher percentage, and that’s not so good. Even properly treated composite tanks and fuel system components can start to fail when you expose them to a high percentage of ethanol for weeks at a time.

    It is frustrating that, with all the small GA airplanes around, we can’t get our hands on lead-free, ethanol-free fuel.I’d be willing to fly to a nearby airport to top up: it would save me in oil changes and gearbox overhauls. It shouldn’t be that hard to obtain: the ethanol is added a the end of the refining process. Evidently there isn’t enough demand to justify a new self-serve tank – and that’s what’s really worrisome.

      • Swift produced a 94UL which was 100 base stock without the Pb.
        80/87 had a lead spec because it was transported in the same lines as 100LL and 100/130 to permit lead washout from the lines.

        80/87 limit was 0.14 g/L, 100LL 0.54 g/L and 100/130 was 1.25 g/L.

    • The big high compression engine aircraft burn most of the fuel. I saw an article once that said 75% so no the guys with low compression engines don’t burn enough fuel to be worth it.

      • Yup – that’s what I meant by “that’s what’s really worrisome.” Small GA may be below viable scale.

      • So it seems. And yet there’s an alert out for my airplane saying “no E10 anymore” because they believe it happened and they saw engine failures in the fleet as a result. Maybe they’re wrong and it was something else; I’m not willing, nor in any position, to find out.

      • Ethanol is very hygroscopic. In most parts of the country, the atmosphere has lots of water in it. In some parts, the summer humidity is near 100% and that air is sucked into vent lines as fuel is burned. Fuel with ethanol will over time absorb enough water to settle out and sink to the bottom of the fuel tanks.

        Doubt this? Try this experiment. Take a 100 or 50 ml graduated cylinder or even a coke bottle. Add water to a mark (25 ml). Add gasoline, cap and shake and let it settle. 10% ETOH will preferentially travel to the water side and raise the water level. The gasoline level will be reduced by 10%. In a graduated cylinder 10ml of water with 40 ml 10%ETOH/gasoline will become 36 ml of gasoline and 14 ml of water/ETOH. Then try it with E85. 10% ETOH means a whole gallon of alcohol in 10 gallons or 6 gallons in a GA fuel tank. That’s a lot of water capacity.

    • Any refinery CAN make it–we’ve had it here in Minnesota for all these years–no lead, no ethanol. You just have to FIND it. Finding it and publishing where it can be purchased isn’t all that hard. Yes, it will mean that you will have to have a dedicated tank–your airport may do that–your service station likely won’t. Will it cost more than “whatchagot auto fuel?” Yes. Will it be cheaper than 100LL? Yes. Would you rather have it than than NO suitable fuel?–That’s what will happen if the “Banish all lead” people get their way.

  10. As a former FBO operator, airport manager, current E series powered Bonanza owner, A&P, drag racer, biker, and lover of all kinds of high performance vehicles, myths die hard. Local dirt track racers would come over to the airport on Friday and Saturday night to buy 5 gallons or so of 100LL avgas. No amount of science information demonstrating the ill affects of running avgas in high performance/high compression circle track cars would convince them to do otherwise. Unleaded racing fuel was widely and easily available in that area. However, in spite of all the evidence, they were convinced they got better performance from avgas because of the lead and the sweet smell similar to auto race fuel. In other words, a placebo affect based on pure myth.

    Likewise, talk to ten different A&P’s, and you will get ten different opinions on the long term damaging affects of running auto fuel, or mogas (the aviation version of auto fuel). No matter what the scientific evidence presents, each one is sure, he/she ( maintaining my PCness) can identify the damaging affects of continued use of non-ethanol auto fuel/mogas. Usually within the diatribe that follows, the A&P cannot get too specific about what those damaging effects really are, but he/she is sure it is not good. I believe this is one of the primary reasons, most aircraft owners pay the extra money for avgas, convinced they are providing far better longevity and performance (just like the local circle track racers) because the the myth that lead in any kind of fuel makes it “more powerful” and is “good for the valves”.

    My E-225-8 was certified for 80/87. I have been running 91 octane non-ethanol auto fuel from my local Walmart, Phillips 66, and a locally owned gas station. I check each batch of gas for ethanol. Then I filter it as I pour it into the Bonanza. I did like wise on our former 0-300 powered 172.

    After 10 years of using locally obtained non-ethanol auto fuel, I have never found a trace of ethanol. The fuel has always been clean, free of contamination. Since I try to fly regularly, I have no aging fuel problems, phase separation, or diminished performance. My airplane has the hand operated wobble pump which make hot starting the pressure carb E series engine a three handed, somewhat comical affair. But with auto fuel it starts much easier on a 100 degree day a few minutes after massive heat soak. Likewise in winter in initial cold start. I am addicted to the sweet smell of racing fuel and 100LL. Auto fuel stinks. But I have never changed a plug in either airplane. Never fouled a plug in either airplane, with far cleaner oil between oil changes. Sticking valves/”morning sickness” is gone, valve guide wear virtually nill, clean oil after 50 hours of use (have spin on oil filters instead of the screen), lower oil consumption, between 8-10% better fuel economy, and on average $2-3 dollars per gallon less fuel costs.

    All of the above is a great cost benefit, performance improvement, less maintenance, and increase cylinder longevity, for me to fall for the sweet smell addiction or the arguments ten A&P’s will give in favor of 100LL. Like all of us auto fuel aficionados, I have to add 100LL on many cross country’s. But I still flight plan giving priority to FBO’s who offer mogas even if it adds some addition distance to the flight. But the majority of the time I fly, I have pure auto fuel in the tanks.

    For the California, Illinois, and many eastern coast state based aviators, I can easily surmise the political climate by the availability or lack of availability of non-ethanol auto fuel. I feel your pain.

    For me, it is worth the effort to use non-ethanol auto fuel, because I like flying a 9.7 GPH at $2-2.50 per gallon, at 150-155kts true. This is a significant reason why I can still own, maintain, and fly an airplane in 2021. I would be flying considerably less at $4-7 dollars per gallon. Plus, I feel good about my airplane not adding to the miniscule amount of lead the current fleet of piston pounders are adding to the atmosphere. I like being a good steward of the planet.

    Swift Fuels has done an extraordinary job bringing their non leaded, certified fuel to the aviation market. But they suffer the same uphill battle against 75 years of lead use with the mythical conception that aircraft engines cannot be safely adapted to non-ethanol auto or mogas that continues to permeate a large portion of aircraft owners and operators. I hope the average aircraft owner supports them when possible. I do when I can.

    Urban myths combined with political pressure and normal grandstanding, powered by all sorts of lobbying, adding the normal, glacial FAA decision-making is just a few reasons why 100LL will be here but debated periodically for a long time. If 100LL is environmentally swept away, anybody with an auto fuel STC aircraft will see their aircraft value rise. New aircraft sales will plummet adding more value to the old Bo. My airplane’s future is more secure than a new SR-22.

  11. The problem doesn’t even exist. This is just Big Government and liberal elites in their constant chipping away at the internal combustion engine. They want to kill this form of pleasure for all of us.

    They don’t care about the lead per se. How much can there possibly be? We burn less than 1% of refined fuel so it doesn’t matter.

    Even if we got rid of lead for some reason then they would attack us for noise we produce.

    Or the plant food (CO2) we produce.

    Or they would make up some new ‘threat’.

    BTW this is one of the reasons I chose a plane with a motor/airframe that has a Mogas STC.

    Fine until they ban Mogas…

    Believe me its an eco-mentalist’s wet dream.

  12. For “The OTHER Jim H” and William K (above)–thumbs up!

    “Perfect is the enemy of the Good”–Voltaire

    This indeed is a “tempest in a teapot”–a problem so small that it is almost unmeasurable.–yet “do-gooders” will not rest until EVERY trace of lead is gone.

    It is said that “It took God to make a Perfect World”–yet that perfect world no longer exists–despite the best effort of mankind. Even beauty queens sometimes have a “beauty mark”–something that draws attention away from true beauty. That does not mean they are UGLY–Sometimes you are better off to LIVE with a little “imperfection.”

    The failure of government to achieve the “perfect” (at a disruptive cost of millions of dollars) is an example of THEIR failure–not of the product.

  13. You are wise Jim. Your comment demonstrates understanding of the world and the Word.

    I wish our government was wise but Samuel made it clear we have only one wise King.

  14. The problem most certainly exists. It existed when I started to fly, and it exists now. Lead is gumming up our engines. That IS the problem, as far as I’m concerned.

  15. This issue was used as the reason to schedule the closing of San Jose Reid Hillview Airport for 2031.

    No matter that a major highway with traffic of tens of thousands of cars per day is adjacent to the airport.

    If you read the link below, you can see the fuzzy reasons used by local government. Affordable housing is a red herring since developers aggressivly resist building it, and the pollution from local highways dwarfs any lead from avgas. Risk from accidents is also mentioned, but nobody asked residents to buy a house nearby the airport, built in 1965.

    What’s not mentioned is the benefits of an airport, and the impossibility of building a replacement in that area. Most of SJC GA was asked to relocate about two decades ago, and now RHV tenants will have to relocate again.

    No parking vacancies at SJC: