Are you concerned about exposure to vapor from your eyelash extension adhesive?  If you're wearing anything other than a mask that's rated for Nuisance Level Organic Vapors, you aren't protecting yourself as well as you might hope.  

What do you think of when you hear "Formaldehyde"? Chemicals? Cigarettes? Dead bodies? Scary stuff.  You may have noticed some manufacturers labeling their adhesive as "Formaldehyde Free".  ...But what does this mean?