Well I came across this academic paper about the toxicity of solvents. This is an extreme case in which a painter painted walk in fridges, often with the door shut, with old time gloss. Often getting drunk on the fumes. I read most of it and the upshot is if it you are using solvent based in an unventilated space, such as a hallway, wear a mask.
Personally I use a mask as soon as the lid comes off any solvent based paint, it is lazy not to in my book. This mask is so comfortable you'll forget you are wearing it.