That is the dry lube they use. I have cast my own bullets for years and there is no lead dust that occurs unless you are grinding, filing, sanding the lead. Use the bullets they are perfectly safe. Wash your hands after handling ANY loading component.
This seems like a very reasonable and moderate answer.
These days I shoot very, very little lead myself, and all of that Hi-Tek coated. The last time I bought lead bullets with the waffle pattern on the shank, it was a feature to hold Alox or some other brownish wax bullet lube. Gosh, that was in the late 70's.
You're thinking correctly though. You
do want to minimize breathing any kind of dust associated with reloading.... tumbling media dust, spent primer smut, the dust you described in your boxes, the dust on the reloading room floor. By that, I
don't mean full HazMat suits and respirators, but rather
reasonable and regular housekeeping steps, such as....
• Possibly opening that box in the yard. Placing the contents in a sieve and leaving all the loose bits outdoors.
• Wet and dry tumbling outdoors
• Regular vacuuming of the reloading area
• Using a spent primer collector system which takes everything to a sealed container
• Regular filter changes in the reloading room and vacuum
• Observing good hygiene... Washing of clothes and hands
And even these moderate steps will be total
overkill.
Hope this helps.