Yup, I used to clean parts in leaded gasoline without gloves, but that doesn’t mean it was a good idea. We used to blow off brake parts with compressed air, too, and that wasn’t a good idea either. Have I got cancer as a result? No (or at least not so far). But a single data point is almost meaningless. After all, if the stuff was so immediately toxic that it caused instant death, obviously nobody would be careless with it. And the fact that asbestos is “naturally occurring” doesn’t mean a damn thing. The plague and arsenic are natural as well.
So we are dealing with substances that WILL cause death and disability on a percentage basis, roughly proportional to the exposure. The reasonable approach, then, is to limit our exposure. Brake parts should be cleaned with gloved hands using rags and sparingly with “brake cleaners” (which have their own hazards, but sure work well, eh?). The more careful among us would use dust masks approved for asbestos as well (likely not the typical throwaway sort, but I don’t know this).
Finally, the issue of brake dust in the environment: I once attended an SAE paper presentation that as i recall purported to show that brake lining asbestos changes form when it is heated via the friction of stopping the vehicle, and therefore isn’t hazardous once it sloughs off the pad or shoe or clutch disc. Considering that so much b.s. has been slung on behalf of those who have a vested interest in selling toxic stuff, I am skeptical of such claims. Obviously there is a LOT of such dust in our environment; it won’t surprise me to find that this is a driver of at least a percentage of cancer cases in the general public. I am not a toxicologist, chemist, or epidemiologist, however.
It would behoove us all to take reasonable precautions, including when dealing with wire looms and insulation, which often in the old days contained asbestos. And it is true that there is no USA restriction on asbestos in brake pads, for example, although you can buy “asbestos-free” pads. All of life involves tradeoffs; let’s be sensible and try to hit the “sweet spot” of care and economy vs. hazard.