A) Lobar bronchus from air-exposed rabbit showing normal airway structure. B) Lobar bronchus from chlorine-exposed rabbit showing sloughed epithelium (arrow) and repairing epithelium that appears thicker than at 6 h (arrowheads). C) Section from air-exposed rabbit showing normal structure of small bronchiole, terminal bronchiole, and alveoli. D) Section from chlorine-exposed rabbit showing sloughed epithelium in small bronchiole (arrowhead), inflammation (short arrow), and alveolar flooding adjacent to terminal bronchiole (long arrows). Scale bar in panel D represents 25 µm for A and B, 100 µm for C and D. Results are representative of 10 chlorine-exposed and 5 sham-exposed rabbits.