Symptoms appear 4-8 hours after exposure and may resemble anything from a cold to pneumonia. Scar tissue forms permanently in the lungs. Repeated exposure increases this tissue damage and causes shortness of breath that can become so severe the victim finds it hard to even get out of a chair. However, TODS does not produce long-term illness or cause permanent lung damage. To contract TODS, you must inhale massive amounts of moldy dust.
Nuisance dusts are mostly inorganic in nature.
Inhaling them usually doesn't cause an allergic reaction, although repeated exposure can harden the lung tissue, reducing oxygen intake and increasing vulnerability to respiratory diseases like pneumonia, tuberculosis and bronchitis. The unit must seal well around the nose and mouth to be effective. Facial hair, even one day's growth, can prevent a good seal.