It’s pretty incredible to me that it’s still allowed, especially around developing brains.
Two strokes (Even the high revving 100cc classes) in Europe have been unleaded since the early 90’s.
Of note there’s a discussion here: Leaded Race Fuel
I’m not sure what mask would work with the lead from burned gas/TEL, interesting question.
My solution was to not take the kids to the track anymore and just build my own.
That said, I’m not too keen on going racing again myself with leaded fuel. I used to road race where you’re drafting a lot. The engine nut in me loves the smell of leaded gas. Two strokes especially love it as the lead forms a dry lube.
However I have a family history of cognitive decline that I’d rather not accelerate.