Abstract: An improved breathing protective apparatus having an inhalation regulator and a primary source of breathing air supplied to the user through a pressure line, and an exhalation regulator with a return line connected to a vacuum source to remove exhaust gases from the work area is disclosed. The apparatus also has a positive pressure and free flowing regulator which provides an extra measure of safety in a toxic environment and provides low breathing resistance under high work load conditions. The arrangement is such that if the exhalation regulator is bypassed for exhaust without vacuum conditions, positive pressure and the free flowing regulator are automatically eliminated to save emergency air for escape of the user from a contaminated environment.