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Comment by jccooper | Hacker News Reader

For context, leaded gasoline phase-out began in 1973, based on the 1970 Clean Air Act. It was largely gone in the US by the 80s but not officially eliminated (except for General Aviation) until 1996. Other countries continued to use leaded gasoline, largely in Africa and the Middle East; the UN started an effort in 2002 to eliminate it in those places still using it. In July 2021, the last stocks of leaded gasoline (in Algeria) were exhausted (probably literally).

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And we still use leaded fuel in aviation. [1]

1. https://www.faa.gov/about/initiatives/avgas

GA pilot here. This is true and most of us don't like using leaded gas either. It's nasty stuff that leads to increased wear on our engines, is more expensive, and is increasingly used as justification for closing airports. Plus we're exposed to it when fueling our planes.

However, it's worth mentioning that recently the first unleaded avgas, G100UL, was approved by the FAA. We're trying to move away from 100LL (leaded avgas) and are finally making some progress on that front.

https://gami.com/g100ul/g100ul.php

I agree with you except the increased wear. Lead is a lubricant and is/was an additive introduced to intentionally decrease wear.

That is largely why the FAA is reluctant to certify older high-compression engines for non-leaded fuel. AFAIK

Yeah in the US I recall in 1991 or 92 the pumps had "UNLEADED" in great big letters running up the side of them. My dad's '77 chevy had a gas gauge near the center console that said "UNLEADED FUEL ONLY".

There's been another push to get rid of leaded gas in aviation but studies show that it's virtually undetectable in the environment.

They made the gas tank filler hole a smaller diameter for unleaded gas cars, so that the leaded nozzles wouldn't fit.

https://uiobservatory.com/2010/how-intelligent-design-saved-....

Source? I have no reason to doubt you but would love to see where those data. Most of what I heard is that "lead exposure above zero is significant" and "if you're living near an airport, especially one serving smaller plans, you are being exposed".

This is specific to the reid-hillview county airport, north of san jose. It was in the news last fall. I can't/won't look for the exact broadcast, but the spokesperson for the airport was quick to point out that there's no detectable lead in the air. The FAA is not convinced either and has no intention of shutting down the airport.

At the bottom here is a link to the studies presented to the local government in an attempt to shut down the airport by local residents: https://news.sccgov.org/newsroom/reid-hillview-airport-airbo...

Here is a PDF of the "airborne lead study" which in fact only talks about blood lead levels, and does not include a single measurement of lead in the environment, oddly.: https://news.sccgov.org/sites/g/files/exjcpb956/files/docume...

I don't work for anything related to aviation or petrol, quite the opposite, and I don't have any interest in it, just was suprised to hear the FAA say that there's no detectable lead in the environment, and then a lead blood level study trying to argue otherwise. In the study they do admit that 25% of the homes in the study were built before 1960 (which I thought was an odd year to pick, as lead paint wasn't banned until almost 20 years later (1978), and I'd wager 65%+ of the homes there were built 1960-1978).

That's about as much time as I have to look down that rabbit-hole. I may be convinced, but there's enough cherry-picked data to make a very gray issue questionable. Looks like nationwide BLL is about 1.50 ug/Dl and in the homes less than a thousand feet directly downwind of the airport it was 1.70, and a child in a typical lead paint home was 1.90

It would have been much more convincing (and conclusive), to me, if there was a measurable amount of lead, particularly downwind, in the areas with the higher blood lead levels. But those readings either were not done, or were absent in the report.

https://www.aopa.org/news-and-media/all-news/2022/march/09/c...

The AOPA link has a letter that addresses some of the points you made and much more. Thanks for the interest. Save Reid Hillview

I remember the UK in the 90s/00s had unleaded written on the pump too, but there was no leaded option.

Actually, I think I have a vague memory pre-millennium of there being leaded pumps (typically red handle vs the green unleaded)

Given that you can smell the jet fuel downwind from an airport, I’d be greatly suspicious of those studies. They don’t seem to pass the smell test.

On one hand, benzene goes much farther than any lead-containing organic compound, and the dispersal is exponential, so it's really much farther.

On the other hand, the thing is literally being dispersed from the high-up, so who knows. It is really a strange result, as one should expect detectable differences even if not large enough to matter. Is water carrying it away?

Leaded gas used in general aviation is not jet fuel. Slightly higher octane than "car" fuel, but definitely not jet fuel which is basically kerosene. I could be wrong, but I don't think you could smell the difference between leaded and non-leaded fuel in exhaust.

If you can smell jet fuel, it’s because there is a jet fuel leak somewhere.

That has zero relationship to exhaust from avgas.

Jet fuel is kerosene, a close relative to rocket fuel (RP-1) and would probably run in a diesel engine for quite a while if you tried (don't try this). Avgas is.... automotive gasoline with some additives, specifically lead based octane booster. They're very different products.

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