MarieAnn -- Kervin's book is excellent, but can be confusing at times. Nonetheless, you definitely ought to have it in your personal library. (A review of it is here:
http://sgb-midatlantic.org/book_revi...n%20You%20Ever)
You might also look at this useful article on ventilation for beadmaking studios:
http://www.wetcanvas.com/Articles2/9304/202/
Jan