In a program of inhalation studies with industrial plastic dusts, a generating system has been developed which permits consistent levels of respirable particles. In this system, preground dust is mixed in a fluidizing generator with a high-speed fan. The air-dust mixture is aspirated into a small baffling chamber and then piped directly into the inhalation chamber. The design of this system and its application to preliminary inhalation studies are discussed. Concentration and particle size data are presented.