Asbestos is also naturally occurring and as a result there's an ambient level of asbestos in the air regardless of how hard you regulate.

I find asbestos to be such fascinating substance. As a kid I thought it was cool as hell ("a fluffy rock!?") and even now I think it's pretty neat in its natural form. Because asbestos has so many useful properties - ridiculously insulating and non-flammable - many of the substances that replaced the asbestos are the PFAS this sentence is complaining about. As far as I know there's still not a good non-PFAS substitute in many cases.