And there are other neurotoxic compounds still in common use, such as mercury-aluminium-amalgam for cheap dental work. That would also confound all the simple studies. I'm afraid there can't be a firm conclusion without an in-depth study of heavy metal prevalence in bloodstream and bones vs. criminal behavior. Just plotting sales figures of leaded gas vs. murder rates doesn't say anything. Any more elaborate study is of course smaller and more expensive, so won't be done as easily.

Very few dentists in USA use amalgam, and certainly not on patients who don't already have amalgam such as children. The moment one orders amalgam one starts getting letters from EPA inquiring about the status of one's very expensive evacuation air amalgam separator. (It's true that everything dentists buy is expensive, but that's not a reason to seek out something else to have to buy.) Properly applied composite fillings have retention nearly as good as amalgam, and of course much better appearance.

My insurance only covers amalgam. If that is common, then those without the means to pay the difference are likely to end up with amalgam.

In practice, that's a way to reduce claims rather than a way to encourage a particular filling material.

I think this is absolutely correct because very few dental offices still perform amalgam fillings at all.

I have amalgam fillings from about 2010 because the dentist didn't offer me composite. My new dentist does only do composite.

Another downside to amalgam fillings is that they require more drilling (and thus more tooth removal) than composite fillings.

they still use that? even when it's a known neurotoxin?

I had the impression (although I can't remember where from) that amalgam fillings were surprisingly benign.

They're small, leach surprisingly little, and what they do leach is in a form that isn't readily bio-available.

Which isn't to say they're completely harmless, just not so bad as you might expect.

Your impression is correct. The mercury is quite chemically bound.

The caveat is that when it is removed, it may not be so bound.

makes sense thanks for sharing

The alternative to amalgam is commonly composite fillings which are BPA.

There is still gold and ceramics. But both are of course more expensive.

Also avgas still mostly has lead in it: https://en.wikipedia.org/wiki/Avgas

Just a couple of days ago we discussed the first approved 100 octane unleaded avgas. One hopes this can scale up quickly and replace the leaded 100LL.

https://news.ycombinator.com/item?id=27983845

With as conservative as aviation is, and as long as airplanes last, I doubt anything about it will be quick. I’m amazed it has taken this long to get a single approved 100LL replacement, considering high octane unleaded fuels have existed for decades.

> With as conservative as aviation is, and as long as airplanes last, I doubt anything about it will be quick.

You may well be right.

> I’m amazed it has taken this long to get a single approved 100LL replacement, considering high octane unleaded fuels have existed for decades.

Outside of some specialized racing fuels, no. And nothing fulfilling the other requirements (distillation curve, vapour pressure, etc etc) of 100 octane aviation gasoline (this is measured with the MON procedure, as opposed to RON or AKI you'll find at your local gas station) at somewhat reasonable cost has previously been introduced.

I think the reasons why it has taken so long are 1) it's a genuinely hard problem 2) it's not a very large market.

I’m aware that it’s MON (there are race fuels above 100 MON) and that there are different requirements for operating at altitude. Obviously it’s a specific application with specific requirements.

I think the problem would have been solved a lot sooner if there was any urgency to switch, either by the people buying it, or by regulators.

The switch with automotive fuels was easy. Cars are disposable by comparison and regulators banned lead-burning ones out of existence.

Interestingly here it's the wealthier inner-city suburbs where lead paint was commonly used when the houses were built.

Advice seems to be leave it alone unless it's flaking.

My experience here mirrors that. I just assumed that the lead paint was more expensive and the builders of my old multi-family went with duller paints. No lead to be found!

Lead paint is not an immediate issue unless it is flaking or someone does something to it.

Yeah, the elephant in the room is leaded gasoline insofar as the lead-crime hypothesis is concerned. Unlike paint, lead in the exhaust spreads out across the entire community in a form that can be easily inhaled.