: While organic vapor cartridges are good for epoxy (while mixing and
: applying), they are nearly useless against fiberglass (and cured epoxy)

Good point! I should have mentioned my respirator uses a stacked configuration with both organic and particulate filters. Actually, it is quite easy to tell if your getting epoxy/glass dust - at least for me. I get an immediate sore throat/sinus sensation. Pretty nasty!

Bill