Hazers and Actors

So I'm doing a small musical theatre concert. Got a few lights, nice cavenous black box space with a few wings either side, no set what so ever and no cyc, so not much to really work with. Figured some haze would give a nice atmosphere and help to give the space some more depth and intrigue. This is not an uncommon circumstance I find myself in as most of the venues I have worked in as a lighting designer have been like this and I generally always use a bit of haze. I see it used in professional theatre, dance, television, most areas of performance really, but in the amateur musical theatre scene, I always get the same response from the actors. "It's making me cough!".."It's affecting my singing!".."I have a dry throat".. etc etc. So initially I was concerned that maybe the use of haze really does affect performers respiratory system, but then I've been told by many other people (techs, actors, directors, average joes) that it is purely a psychological thing and that simply seeing the haze makes a person feel as if they are slightly asfixiated. The fluid doesn't not emit a toxic haze and unless you have a severe allegy to whatever is in the fluid, then it should not affect you. What are your thoughts, as either a performer, director or tech?