"Todd Fatheree" wrote in
:

Well, I'm not sure this is a serious professional type of job. And
somehow, I doubt a one-time use is likely to cause "permanent lung
damage".

Probably not, but you might want to google "acute silicosis" before
getting too confident. Granitic rocks are the worst for this.

If I were doing it, I'd
probably still wear a mask

Wearing a mask would be very wise. Dumping water down the hole
periodically is also a good idea (besides keeping down the dust,
it also cools the bit & helps clear the chips out of the hole).

John