The MKII-B Protective Mask protects the user from Radioactive dust, cyanogens (cyanide), chlorides, arsine, phosgene, chloropicrin, bromomethane, lewisite gas, mustard gas, sarin, vx gas, toxic smoke, toxic fumes, benzene, hydrogen phosphide, chlorine, acetone, alcohols, anilines, carbon disulfide, carbon tetrachloride, nitroalkanes, biological bacteria such as the plague, cholera, anthrax, influenza.