I used to work in an isocyanate unit and can agree that it is bad stuff. But in paint I'm not sure that it's not the benzene and other solvents that causes irritation. As far as an scba(self contained breathing apparatis) Scott makes many units that use cannisters instead of an air bottle. I have tried these masks out on other many harsh chemical and they seem to work great against odors. I plan to use one when I paint my car. If you go with a scba/mask, I would deffinately go with scott.
http://www.scotthealthsafety.com/Ame...promask25.aspx