Catalyzes the heme-dependent decomposition of chlorite to O(2) and chloride with high efficiency and specificity. Used to detoxify chlorite, a by-product of the reduction of perchlorate, a primarily anthropogenic pollutant, in perchlorate-respiring bacteria. chloride + O2 = chlorite Binds 1 heme b (iron(II)-protoporphyrin IX) group per monomer. Homopentamer. Expressed under aerobic conditions. Significantly increased upon shift to anaerobic conditions. Belongs to the chlorite dismutase family.