But then again, now everything is bad for you
My dad is 82 and an ex powerhouse engineer for the local blanket factories.
In his time he swept the 150 foot chimneys by hand on a bosons chair, mixed asbestos lagging by hand in a dustbin, and cleaned the water and
from mercury used in the temperature gauges by hand with a rag in a bucket....all of the above will apparently kill you at the drop of a hat
After that he worked as a Fiat mechanic and god only knows how many times his hands were immersed in dirty engine
Still going strong tho...as you say, its hard to work out an acceptable level
Going back to the sand.....
If you scoop a box of sand off the beach in certain states in the US and try to ship it home, you have to add a Carcinogen warning to the box because it will contain particles below the acceptable size...again its all about the exposure levels