My guess is that the leaded gasoline was a bigger contributor than kits like this. As you would almost always be breathing in the lead smog.

I think lead gas by far for the reason the other person mentioned. Everyone got exposure by existing and breathing.

With other stuff, it depends on your interaction with it. Lead paint was and still is pretty safe unless you sand it and breathe it in which is unfortunately easy to do in that context, or it flakes off and you're a kid who likes the sweet tasting corn flakes made of wall.

These toys were probably fine if you had air circulation, didn't chew on your toys, and washed your hands before you ate. But there of course were kids who probably thought it was funny you could dent them by biting them...

We stick lead on exterior parts of houses. Just don't lick it

Seriously, though. A lot of what's wrong with US politics is traceable to leaded gasoline exposure in childhood. It hit the Boomers worst -- while earlier generations had grown up with leaded gas, they had less of it because cars weren't as popular and widespread back then. Generations after the Boomers had the benefit of leaded gas being phased out and banned. But the Boomers grew up during peak leaded gas times, when we were still using it in every car and there were more cars being driven more than ever before.

Seriously ... look at the symptoms of childhood lead exposure, especially as it relates to the victims when they begin to age. It's like a perfect checklist of modern conservatism.