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I remain shocked how we in the United States knowingly poisoned generations with leaded gasoline.

https://www.smithsonianmag.com/smart-news/leaded-gas-poison-...

In searching for a substance that made gasoline less flammable (and hence stopped it from igniting outside of a cylinder, i.e. "knocking") we tried everything including adding melted butter! Lead along with a lot of other things worked well but we went with lead and poisoned generations of people.

Many blame it for the rise in violent crime from the 1960s to 1990s:

https://www.forbes.com/sites/alexknapp/2013/01/03/how-lead-c...

Nobody seems to care about any of this.

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> Nobody seems to care about any of this.

Leaded petrol has been banned from sale at gas stations by every country in the world. [0] Unlike many important issues (such as overuse of antibiotics), it did receive the attention it deserved, at least eventually.

Work is ongoing in phasing out the use of leaded fuels in aviation. I think it's mostly a matter of testing existing aviation-approved engines to ensure they still perform as required on the various unleaded petrol blends they hope to transition to.

(As I understand it though, leaded paint is far more of a problem in terms of lead poisoning, than use of leaded petrol in aviation. I was still surprised the article made no mention of aviation.)

Aside: Someone at Cessna apparently thinks the transition away from leaded petrol will reduce carbon footprint. [1]

[0] https://www.nationalgeographic.com/environment/article/final...

[1] https://www.flyer.co.uk/cessna-singles-ok-to-use-unleaded-fu...

Same inventor of TEL additive for leaded gasoline also played a key role in developing CFC refrigerants (“Freon”) and later was killed by one of his own mechanical inventions.

https://en.m.wikipedia.org/wiki/Thomas_Midgley_Jr.

Leaded fuel is still widely used in piston engine airplanes (most small airplanes).

https://www.nbcnews.com/business/business-news/leaded-gas-wa...

There has recently been some real progress in this front, with the FAA approving unleaded fuel in about 600 engine models. Basically, aviators have been waiting a long time for the government to stop forcing them to use leaded fuel.

An aside, but certainly not outside of a cylinder? AFAIK knocking means premature ignition within the hot cylinder during the compression stroke, and/or detonation of the fuel/air mix rather than the desired deflagration.

Lead also helps with valve seats lasting longer. Automakers switched to hardened valve seats in the 70's when lead was taken out of gas.

AFAIU, expensive (or read: less cost-sensitive) engines designed for operating at close to rated power for extended times, like airplane engines, have used hardened valve seats since the 1920'ies or so.

Likely - I can't remember if it's Ford or Chevrolet (or both) but their big-block engines used hardened seats from the start, only the small-blocks had to switch.

And some airplane engines still use leaded gas.

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