This dust may contain a mixture of many substances including ground up plant matter, fiber, bacteria, fungi, soil, pesticides, non-cotton matter, and other contaminants. The first symptoms of disease are difficulty in breathing or perhaps a tightness across the chest which is particularly noticeable on the first day back at work after a worker has been off for a few days.
Workers also cough up phlegm or mucous.
While earlier breathing difficulties may be reversible, damage at the advanced stages of the disease is permanent and disabling. Workers who develop brown lung may have to retire early because they are so short of breath they cannot do their normal jobs or even carry out simple tasks. Exposure to cotton dust also leads to increased risk of chronic bronchitis and emphysema. At the time the final standard was published, as many as 100,000 workers in the cotton industry were at risk from cotton dust exposure. An estimated 35,000 individuals are disabled from byssinosis as a result of exposure to cotton dust.