https://www.baltimoresun.com/news/bs-xpm-2006-05-04-06050400...
https://canada.autonews.com/article/20180107/CANADA/18010983...
Asbestos isn't that harmful, until it goes airborne. My understanding from research (I worked expanding a landfill that took asbestos at one point). is that the particles are too small to be caught by our bodies defenses and when it ends up in your lungs its cancerous. Asbestos in brakes seems like a bad idea.
I believe a lot of the stopping power comes from ceramic cinders in the pads. Those showed up in high end bicycle brake pads about 25 years ago, and I think they were old news in high performance cars before that. I have a fuzzy recollection that they trickled down into mid-tier vehicles not long after that. 2000-ish?