Quote Originally Posted by rolodave View Post
Shale is naturally radioactive.
Sand and limestone are not.


I do not know if shale exposure or ingestion is hazardous.
Depends on the particular formation the shale came from. The Marcellus Shale found back east through West Virginia is well known to be Radioactive.

The problem isn't so much handling a chunk of the stuff it's when it's bought up as overburden (waste rock) and it's concentrated in piles or thrown into rivers where it breaks down.