I'm a chemist. I don't believe that TEG, tri ethylene glycol, is especially harmful. It's a fairly good antiseptic. If it was sprayed in the afternoon and I attended an evening performance, I wouldn't be concerned (it's already used in the special effects fog machines). But if I'm an usher or actor or stage hand -- the long time effects (especially bronchial infections) might be hazardous. Let the OSHA people check it out first.
