To quote the article linked to:
Our Unique Solutions hazer works like this.
Pump hazers also includes machines which function in the same manner as a fog machine, pumping fluid into a heated chamber where it is vapourized to produce a cloud. Hazers which heat fluid to create an atmospheric effect only use mixtures of water and glycol or glycerine. Spray hazers which atomize fluid can use either a water-based or mineral oil fluid.
Our Unique Solutions hazer works like this.