Workplace and even homes are subject to pollution from a list so long that would be hard to compile but we in the aircraft game might just be exposed to more than most. At the airline I worked for we used a lot of trichlorethylene III for cleaning parts and such but fortunately, it was in relatively small amounts (usually, anyway!). The kid that lived across the street from me was working at Northrup and they had a plating shop with an entire tub of the stuff, used to clean parts before plating. The sheet metal guys unfortunately found out the stuff is great for getting all the crud off your hands and arms. Since they were mainly young guys just starting families and such, there were 5 or 6 that had babies born with some pretty severe birth defects, which were traced back to the tub of trike. Horrible stuff when it comes to after effects on your body but there's little else that cleans like it did.
When it comes to products such as MMO having McNasties in it, the amount is so low that you'd just about have to bathe in the stuff... or maybe breath in the mist when using it to lube your air tools (kind of hard to hold your breath long enough, the stuff stays in the air for a long time, especially in the shop!). As has been said, there's nothing in the way of dusts or mists you can breath in that are good for you in the shop, so depending on how much and how often, the use of a vapor mask is highly recommended!
Cheers,
crkckr
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