I was surprised recently to learn that general aviation aircraft still use leaded fuel. I wonder how much lead we are all still exposed to because of this? Is there some technical reason why it can't be removed?
AFAIK there's no regulation in US that will force reformulation with lead-free compounds (which do exist), the best the US has is California's Prop 65, which provides a bunch of useless labels which people are trained to ignore. What a disaster.
It's a fucking farce that any lead is ever allowed to be purposely added to plumbing materials labeled "lead free". However, nowadays most such labeled materials actually are lead-free. All the big brass suppliers -- Concast, Chase, Viega, Mueller, others -- produce actual lead-free brass and bronze, with no more than trace and incidental amounts of lead.
> AFAIK there's no regulation in US that will force reformulation with lead-free compounds
Correct, nothing nation-wide, although companies that sell stuff to the EU often make RoHS/REACH compliant lead-free products for all markets, simply as a matter of efficiency.
You're also right, Prop 65 is a great example of smart and necessary idea that was crafted into a useless law. Labels without any actual market restrictions are an invitation to gaming by manufacturers, and apathy by consumers.
Relevant Article: https://www.scientificamerican.com/article/lead-in-aviation-...
One reason is that alternative octane boosters can cause icing in carburetors and fuel injection systems, resulting in engines cutting out at low temperatures. Improvements in combustion chamber design have helped reduce the reliance on high octane fuel, so I expect the situation will gradually improve.