One other thing that is possibly worth mentioning on the fans (or most any electrical device), is that when there's a failure- like a short circuit because of old or faulty wiring, for instance- that sparks (thus an ignition source) can be created. So while an induction motor is a safe motor, spark-wise, it can still be an ignition point.
The best bet here, IMO, will be to use a new fan (or any electrical component- extension cords, switches, lights, whatever) that has an hour or two of run time on it, previous to be used in the "booth". This might be seen as overly cautious, I don't know. But I wouldn't trust brand new (as in, the first use of a component in the explosive atmosphere) OR too old, either one.
Static can be lessened by painting on a day that isn't cool and dry, and wear cotton clothing/overalls. Probably best to avoid plastic sheeting, for instance.