Abstract: A protective breathing apparatus comprises a breathing gas supply tube fitted into a protective face mask which has an opening to which the tube extends and which has a peripheral sealing lip adapted to seal the mask around the user's face. The mouthpiece is attached to the inner end of the tube into the mask and it is engageable by the user's mouth through association with the mouth for breathing. The mask advantageously includes a thickened area on each side of the person's nose to constrict the nose so that breathing is through the mouth, and the mouthpiece advantageously includes bite nipples which are engageable by the mouth in order to hold the tube in the vicinity of the mouth for breathing. Alternatively, the mouthpiece comprises an end having a plurality of serrations along it which fits into the mouth.