EPA Releases Endangerment Finding On 100LL: EAGLE Responds


The Environmental Protection Agency (EPA) today released its long-anticipated final determination on the danger of leaded aviation gasoline. The finding sets plans in motion to define a “pathway” toward regulation that will ultimately enable a safe transition to a lead-free replacement for high-octane, low-lead fuel (100LL). With the testing still required and opportunities for public comment, that process is likely to take two years, according to FAA Executive Director for Aircraft Certification Service Lirio Liu.

According to the EPA statement: “EPA and FAA have already begun work to consider regulatory options to address lead emissions from aircraft engines and will announce timelines as soon as possible. EPA and FAA will work in partnership and engage all interested stakeholders and the general public as the two agencies develop their separate regulatory actions.” 

Representatives of the Eliminate Aviation Gasoline Lead Emissions (EAGLE) working group held a media briefing directly following the release of the EPA finding. During the online webinar, Liu joined several industry stakeholder participants in stressing—multiple times—that EAGLE and the FAA are firmly committed to ensuring the continued availability of 100LL until a safe and practical replacement can be made universally available. In essence, the message was that ensuring flight safety for aircraft that require higher-octane fuel takes precedence over the risk of prematurely eliminating the availability of 100LL.

Curt Castagna, president and CEO of the National Air Transportation Association, which represents the interests of “a broad array” of aviation service providers, including fuel providers, airports and FBOs, laid out three priorities going forward: developing a suitable fuel, keeping 100LL available in the meantime and helping airports and airport operators effect a smooth transition.

Stakeholders represented at the webinar included:

Mark Baker, president and CEO, Aircraft Owners and Pilots Association (AOPA)
Todd Hauptli, president and CEO, American Association of Airport Executives (AAAE)
Prentiss Searles, director of fuels, marketing and vehicle policy, American Petroleum Institute (API)
Jack Pelton, CEO and chairman, Experimental Aircraft Association (EAA)
Pete Bunce, president and CEO, General Aviation Manufacturers Association (GAMA)
James Viola, president and CEO, Helicopter Association International (HAI)
Curt Castagna, president and CEO, National Air Transportation Association (NATA)
Greg Pecoraro, president, National Association of State Aviation Officials (NASAO)

The next steps involve establishing aircraft emissions standards under the Clean Air Act. Liu said, “The EPA can find that a component causes harm [which is what the endangerment finding is]. The FAA will define the standards.” She reiterated that the FAA approach is focused on safe operation, while the EPA focuses on eliminating harmful emissions. Liu described the timeline going forward as a cooperative effort between the FAA and EPA. “We really have to work in harmony here,” she said.

Mark Phelps
Mark Phelps is a senior editor at AVweb. He is an instrument rated private pilot and former owner of a Grumman American AA1B and a V-tail Bonanza.

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  1. “She reiterated that the FAA approach is focused on safe operation, while the EPA focuses on eliminating harmful emissions.” In this case, the only way that “government is focused on safe operation” mentioned is to eliminate operations by a large part of the fleet–and ceding control to those that propose banning!

    Liu described the timeline going forward as “a cooperative effort between the FAA and EPA. “We really have to work in harmony here,” she said.

    I don’t see any harmony or compromise here–only the EPA “wins.”

    “Compromise is two wolves and a lamb voting on what’s for dinner.”

    • I don’t agree. I don’t think the FAA will consider having the EPA “solve” the matter in any way a loss for their collective bureaucratic buttocks.

      • As an added bonus, we aren’t digging metal sludge out of our engines with every oil change, and doing lean run-ups to burn the lead out of our plugs, and seeing shorter engine lives due to all the lead deposits.

  2. Unless someone is breathing through a mask being fed directly from an airplane’s exhaust pipe, I am absolutely befuddled why this ‘finding’ is even necessary … other than to pick on still another segment of the ICE users.

    These unelected bureaucrats who have pseudo-absolute power over the population have to be stopped. IF this is such a life-and-death issue, put it before Congress for a vote.

    Frankly, they can all kiss my a$$. I don’t usually speak so ‘candidly’ but THIS time … they’ve gone TOO far on an issue that doesn’t amount to much more than a hill of beans on an absolute scale.

    • “IF this is such a life-and-death issue, put it before Congress for a vote.”

      At the moment, Congress can’t even find its own hands and feet. In that sense, it’s a good thing that life-and-death matters are not left to Congress, or we’d all be dead. In any case, Congress *could* overrule the EPA’s finding, but given the current state of Congress, I don’t see that happening any time soon.

      • Congress gave the EPA its authority. EPA long overstepped the bounds of the authority given to it, along with most other executive departments. Congress is at fault for failing to do its job responsibly, instead ceding its powers to the Executive which then stretches what it is allowed to do to the outer limits.
        If this (or any other regulation battle) were truly a life and death matter, we would not all be dead, we would be alive and probably come to better solutions that what we are being given with satisfy paperwork but not real world issues.

    • Ya, I would not worry about the Lead much, you would be dead in about 20 minutes from the CO from the polluting Lyconosauros.

    • Larry S, you’re right. Our ability to keep flying little airplanes doesn’t amount to a hill of beans to the vast majority of the population.

      “If they can’t stop spewing lead, shut them down. My kids shouldn’t have to suffer over some weird hobby for old men.”

      See how that works?

      • Red tape: excessive complexity in official routines and procedures that causes delay or inaction to the frustration of the user.

      • The funny thing is, most of the paperwork is also done. It’s not a big leap to go from an STC that says “buy this piece of paper and you’re good to go” to “you’re good to go by default”.

        The real challenge is political, not technical or regulatory. GAMI didn’t want to play ball with what they clearly saw was a money-sucking dead-end, and so they got shunned for not playing the game.

    • Too bad there isn’t already a pretty straightforward way to enable all the piston engines to run on UL94…

      • Their already is, but it might have some cost involved. For the normal 7.5 to 1 compression ratio turbo charged engines, the addition of a intercooler or larger intercooler will allow the use of UL94 as a replacement for 100LL. For normally aspirated engines with compression ratios above 8.5 to 1, adding water injection will allow the use of UL94. Currently the users of theses engines will keep the rest of the small aircraft fleet hostage as long as they can get away with it. The 100UL fuel solution will be so expensive it will be a further drag on Aviation and may result in further shrinkage in the aviation fleet.

  3. “The next steps involve establishing aircraft emissions standards under the Clean Air Act.”

    With unleaded fuel, gov could mandate catalytic converters? This will get interesting.

    • “Could”, but I don’t really see that happening. It would be a huge regulatory uplift to approve a catalytic converter for all the various aircraft, including a lot of work for the FAA itself. I think it’s more specifically targeted at just coming up with a “no lead emissions” standard.

      • Has there been any adverse regulation anyone has seen coming from an executive department that has caused major disruption and expense? When the Clean Water Act was passed, no one in their right mind ever thought the EPA would attempt to regulate pasture puddles formed by cows recycling water they drank, but they have tried repeatedly under the Waters of the US Regulations, twice, after being struck down by the Court.

        The EPA and the Executive is not concerned about huge regulatory uplifts. To think they won’t try expanding their reach much further is like taking off from Boulder, Colorado, westbound in a 100LL powered airplane with 200 ft ceilings and tops to 15,000. Not believing there is harm that way will be a problem, sooner rather than later.

        • The difference here is that two regulatory agencies are involved. And one thing the FAA doesn’t like is another regulatory agency telling them how they should do things. I’m not at all concerned about the EPA’s 100LL endangerment ruling.

          • That may be true but the secret service and TSA have been walking over the FAA for years. It would be a refreshing change to actually see the FAA exercise it’s exclusive authority over aviation matters.

          • You mean, like when the city of Santa Monica told the FAA it was going to shut down an airport it had promised never, ever to shut down – an airport the FAA was within its rights to take back if Santa Monica ever tried that – and the FAA took a strong position and said “sure – where do we sign?”

            I think catalytic converters on piston engines are not an impossibility. But, they would be an impossibility on turbines, and it would be tough to beat up on the little guys. I’d agree it’s unlikely, but not because the FAA knows how to stand up to other agencies.

        • Please please please put all the bureaucrats in that aircraft. Those aircraft, sorry. But make sure said acft aren’t really airworthy, no use trading otherwise usable hulls.

  4. Sadly, this might be the next step. Emission controls on our aircraft. Despite the fact that fewer aircraft actually get used.

    We have a full compliment of emission controls on our wheel loaders. Also the excavators. You want to see a mess of things to fix? Just wait until this ends up under a hood of a 182 .

    I wouldn’t want to fly it and find out the hard way when that system goes offline…

      • Absolutely! Politics aside, forget the EPA, forget lead’s toxicity for a moment:
        What we (airplane owners/operators) need is a no-lead fuel that has a stable octane rating, a long stable shelf life, and a very low vapor pressure. Now that we have such products in the marketplace, it’s time for the FAA to get off their duffs. What a bureaucratic morass this has become! We (all of us) are the ones who should be pushing this. I’m ready to buy this stuff now. I’m not going to oppose something just because.
        Lead is responsible for a whole host of engine problems. I sure am tired of cleaning “clinkers” out of my plugs every year, and I lean aggressively.
        Like I said, all politics aside…lead sucks!

        • You mean… UL94?

          If only anyone stocked it! I’ve been hoping to find it nearby. So far, the closest is 95 nm away from me.

      • My first vote was for Ronald Reagan. I’ve voted for less than a dozen democrats since then, and only then in non partisan elections or for judgeships.

        The Republicans will not waste one minute of fundraising or potential television time to actually fix a department. To actually do so would require planning to do so BEFORE winning the next congressional election.

        They don’t care that much. They’d rather, similar to the Democrats, talk about how we have to elect them to stop the other guys from making things even worse. That doesn’t take nearly as much work.

  5. George needs an elephant costume. Because he’s in every one of these rooms and no one wants to mention it.

    • Correct sir. Just look what they did to the marine and small engine segment. Said the fuel was permeable through the fuel tanks and hoses. Now fuel tanks are 400% more expensive and the hoses collapse leaving boaters stranded. Add to this no more vented tanks and carb engines pressurize and overflow the carbs creating a spill and fire hazard. Now look at jerry jugs. Not vented so the manufacturers have all kinds of fancy spouts on them which spill 1000 times the fuel than could ever be vented! A disaster!

      • Too right. Just cleaned up a diesel farm tractor fueled by one of those jugs. Spilled more than I got in the tank until I swapped in an old fashioned nozzle and spilt no more $5/gallon diesel.

  6. This issue, like many is 100% political. THIS IS “about flying stuff”. The rhetoric out of your keyboard is the “old leftist attack of deflection”. It’s a uniparty in D.C. Have a vote and weed out those that support general aviation and those that don’t. Just to be clear YOUR WORDS are about as adult as a 3 year old.

  7. Let’s just hope the replacement fuel is as dependable as all priors have been, but it must be available BEFORE the present stuff is outlawed. Sound familiar?

  8. What? The EPA wants to eliminate lead from aviation fuel? Who could have possibly seen that coming (eye roll…)?

    The toxicity of lead has only been known since antiquity. Tetraethyl lead has never been produced in a way that did not result in poisoning of either manufacturing workers, end users, or bystanders. Just about one hundred years ago, when tetraethyl lead was proposed for use as a gasoline additive to improve octane, medical toxicologists informed congress and anyone else who would listen that doing so would cause widespread lead exposure to the detriment of the public’s health. And that is exactly what happened.

    The idea that general aviation should get some kind permanent special permission for use of tetraethyl lead decades after its removal from mogas is not reality-based and the failure to find a substitute for 100LL is not the EPA’s fault.

      • Agree. Continental and Lycoming should have stopped manufacturing engines that require the stuff, at least 30 years ago.

    • Let’s be serious. If we are talking about what the EPA wants it’s to stop private citizens from flying for any reason except those on their agenda. The rest is is just details.

      It amazes me people actually think the environmental community is really about conserving our environment. That’s not what the leadership was ever about.

  9. For Doomsayers and Trolls: There is a version of unleaded 100 octane Avgas nearing the finish line a lot sooner than 2030 that is a simple, certified drop-in replacement for 100LL… All is not lost, and planes will keep flying, because it will take the FAA and EPA bureaucrats a lot longer than that to “negotiate” a regulatory end to 100LL.. And the folks at Innospec in the UK who are the only makers of Tetraethyl lead in the world can’t wait to shut down their plant as well.. As for smog-testing, we can only hope ….

  10. I’m so sick of this EAGLE garbage. Notice how the list of “stakeholders” represented in the webinar doesn’t include anybody from the vendor who has an approved unleaded fuel for every spark-ignition engine in the fleet? Obstructionist bozos.

  11. Two more years, really? Government are experts in dragging programs out, contract this out and have it solved within a year!

  12. I’ve heard and read a LOT of belly aching about this report, but I for one feel that it’s a few decades later than it should have been. 100LL is one of the many albatross hanging around the neck of the General Aviation sector of the aviation industry, and should have been phased out at the same time auto gasoline was mandated to find a better octane booster.

    The environmental impacts, which I’m sorry to have to tell people are very real and very detrimental to our health, are simply one perspective which justifies this statement. I’ve been in the GA sector for well over 30 years and have watched the FAA stifle too many technological innovations related specifically to our community, and this is simply one of those issues. As an owner of a SEL reciprocating engine powered fixed wing aircraft, I’ve had to deal with the multiple negative impacts to my aircraft related to the use of 100LL fuel.

    Because 100LL uses lead as an octane booster, the oil used during normal operations must be capable and effective at scavenging those lead deposits which form in the cylinders and internal components. Because of chemistry (I assume), the only effective oil lubercant option which is capable of effectively scavenging these deposits is the most basic mineral oil-based engine oil formulas. The problem lies in the fact that while the naturally produced and refined mineral engine oils are effective at dealing with the lead deposits, they are incredibly ineffective at adhering to the insides of the cylinder walls or any of the hundreds of other internal engine components which require oil to operate.

    Pilots are told over and over that a GA aircraft powered by a reciprocating engine must never sit unused for more than a couple weeks between operations. They are told that doing so is highly detrimental to the internal engine components, something that doesn’t take translate over to many other machines or vehicles with gasoline engines. I’m my experience, most pilots simply take this warning at it’s word, never really being interested in the “why” to justify it.

    The reason the insides of our GA 100LL powered reciprocating engines turn into the surface of Mars so quickly goes right back to the lead. Again, because of chemistry and smart stuff, mineral-based engine oil has been the most effective type of engine oil at scavenging the lead deposits from the engine which is required to maintain a healthy powerplant. What are tragically INeffective at scavenging lead deposits from internal engine components are the motor oils which blend in a synthetic motor oil, or are developed with 100% synthetic lubercating engine oils.

    You know what synthetic motor oil IS really good at, though? Synthetic motor oil is fantastic at coating, adhering to, and protecting internal engine components for months without being disturbed. A few petroleum companies have tried to blend in synthetic oil into aviation reciprocating engine oils over the years, and all have failed spectacularly. AeroShell is probably the most widely known example of this, which after having to pay a LOT of money to a LOT of angry aircraft owners, pulled the synthetic blend engine oil from the market permanently.

    I for one will be first in line the day an airport in my area launches the sale of G100UL, and hope the petroleum companies which would need to seek FAA approval of a full synthetic aviation motor oil are paying attention and already working the development to coincide with the introduction of non-leaded aviation fuel when it happens. If this report is what it takes to force the FAA to FINALLY let GAMA go into full-scale production of their fully drop in replacement of 100LL, than I thank the EPA for ignoring the political pressures they were dealing with opposing the public release of it.

    • You try leaving an auto sit idle for more than 6 months with the crappy ethanol mixed gas in the tank and see how well it runs! You have a valid argument but leaving any gasoline powered engine idle for a long term with ethanol mix is not good.

  13. “The environmental impacts, which I’m sorry to have to tell people are very real and very detrimental to our health,”

    What is the factual evidence for this statement? I have read the reports–both the air sampling studies and statistical reports. The EPA relies on results from air monitors that they placed inside the fence, in runup areas, to claim that toxic levels of lead are in the air. This violated the EPA’s own study protocols and the air monitor manufacturer’s directions for use in placing the monitors where there is no “ambient air” i.e., air that people breathe. EPA did this at Santa Monica, San Carlos and Carlsbad in California.

    The studies at San Carlos and Carlsbad were supposed to be scoping studies to determine how to PROPERLY evaluate the amount of lead in air, followed by further studies that were to be designed based on the results of the preliminary scoping study. However, once the EPA and local air quality management districts got a couple of hits inside the fence, they received friendly FOIA requests from environmental groups demanding disclosure of these bogus results. They released the results, and the rest is now history. There never were any follow-on studies, allegedly due to lack of funding.

    BTW, the air monitors at Reid Hillview never got a single hit in excess of EPA’s threshold, and monitoring was discontinued after several years. The statistical studies find correlation, but not claim to find causation, and they fail to account for other lead sources (power plants, paint production plants, residential lead paint, lead arsenate pesticides, and background lead remaining from decades of automotive fuel use). Michael McDonald did an excellent job refuting the conclusions drawn by the politicians and the anti-airport advocates at Reid-Hillview. https://www.aopa.org/news-and-media/all-news/2022/march/09/california-pilot-points-out-lead-fallacies

    The battle has been lost, since the alphabet groups threw in the towel on challenging the faulty studies. It’s just unfortunate, and galling, that so many pilots have themselves fallen for this narrative. I’ve lived most of my life around airports. Our kids were raised in Cessnas. We’ve had all of our blood tested for lead, with no abnormal results.

    I care deeply about the environment, including air and water quality. A lot of good has come from the Clean Water Act and the Clean Air Act. Most of it happened within the first two decades after passage. We are now left with a bureaucracy seeking any incremental project to justify its continued existence. The way EPA air division manipulated the studies regarding leaded avgas destroyed my faith in government scientists.