Silicosis - the oldest known occupational disease, usually affects sandblasters, rock cutters, and miners where free crystalline silica dust ( silicon dioxide ) is inhaled by the workers. Medical treatment for silicosis is limited . Silicosis is usually diagnosed by a simple chest x-ray , revealing the presence of multiple small opacities on the film. Silicosis usually is preventable , if proper warnings and equipment are used and the worker is made aware of causes of this deadly disease and instructed on how to prevent such exposures.