According to the American Lung Association (ALA), there are two basic forms of pneumoconiosis: coal workers' pneumoconiosis, or CWP, and progressive massive fibrosis, or PMF. CWP, also known as simple pneumoconiosis, causes small amounts of scarring in the lungs. PMF, also called complicated pneumoconiosis, involves widespread scarring over lung tissue.
CWP is further broken down into black lung, brown lung and popcorn lung, depending on the type of dust inhaled. Johns Hopkins Medicine Health Library reveals that black lung disease occurs when miners inhale coal dust. Brown lung disease happens when workers breathe cotton fibers, asbestos and silica. Diacetyl, a butter flavoring in movie popcorn, causes popcorn lung. All of these substances lead to pneumoconiosis over many years of exposure.
PMF has worse symptoms than CWP. Symptoms of the more complicated type of pneumoconiosis include coughing, lots of phlegm, shortness of breath and difficulty breathing, according to Johns Hopkins. Simple pneumoconiosis may include few or mild symptoms. Awareness of pneumoconiosis occurs after a chest X-ray detects mild scar tissue in the lungs.
Risk factors for pneumoconiosis include exposure to large amounts of dust, exposure for long periods of time and smoking tobacco. Pneumoconiosis hardens lung tissue, inflames air sacs inside the lungs and develops scar tissue between these lung sacs. The ALA states there is no known cure for pneumoconiosis as of August 2014.