I'm wondering the same. Is it accidental contamination or are they doing it deliberately? Out of malice or out of ignorance? Or is it someone else upstream putting radioactive materials in the products that end up being used as a coating? Again, why, ignorance or malice or something else?
That seems incorrect, or least depends on where you draw the line on "abundant" Thorium, at atomic number 90, is one of the rarest elements. [0] It falls middle of the pack in terms of presence in the Earth's crust, but after the first dozen or so, most elements are-- relative to that first dozen-- extremely rare. Thorium is about 6ppm.
>and has mundane uses.
Lots of things have mundane uses while being extremely dangerous if misused. Chlorine is about 20x more abundant, has plenty of mundane uses, and is also poisonous. Thorium is a cancer-causing element, and over the past decades thorium has been systematically removed from any product or industrial process that does not require it.
I think it's safe to say that it's a bad idea, and presents a least some risk, to include it in consumer product worn on your body.
