Pneumoconiosis Symptoms, Causes and Risk Factors
The most common symptoms of pneumoconiosis are cough and shortness of breath. The risk is generally higher when people have been exposed to mineral dusts in high concentrations and/or for long periods of time. Inadequate or inconsistent use of personal protective equipment (PPE) such as respirators (specially fitted protective masks) is another risk factor since preventing dusts from being inhaled will also prevent pneumoconiosis. Pneumoconiosis does not generally occur from environmental (non-workplace) exposures since dust levels in the environment are much lower.
What Are the Symptoms of Pneumoconiosis
Patients with pneumoconiosis may have no symptoms at all, particularly early in the disease. Symptoms can include cough, with or without mucous (sputum) production, or chest tightness. Many patients complain of shortness of breath. Patients may first notice getting more breathless or winded with activity, like walking or climbing stairs. Some patients may feel breathless even when they are at rest.
If pneumoconiosis involves a large part of the lungs or causes a lot of scarring, oxygen may be prevented from easily reaching the blood during breathing. This results in hypoxemia (low blood oxygen levels). Hypoxemia may only be present during activity or while sleeping. Hypoxemia may be present all the time if pneumoconiosis is severe or progresses. Many patients with hypoxemia do not know that their oxygen levels are low because hypoxemia itself does not always cause symptoms like breathlessness. Oxygen in the blood delivers oxygen to all the internal organs, so recognizing hypoxemia is important to prevent stress on other organs, like the heart and brain.
What Causes Pneumoconiosis?
Many dusts can cause pneumoconiosis. The most common workplace mineral dusts that are known to cause pneumoconiosis are asbestos, silica (rock and sand dust), and coal dust.
What Are Risk Factors?
Pneumoconiosis includes asbestosis, silicosis and coal workers' pneumoconiosis (CWP). CWP is sometimes called "Black Lung Disease" because the charcoal dust in the lungs can turn them black in color. Below are the dusts which cause these diseases.
Asbestos fibers are very durable and resistant to heat, leading to their use in insulation and fireproofing, as well as in textile manufacturing. Examples of workers who might be exposed to asbestos include plumbers, roofers, mechanics and shipyard workers, including naval officers. People are at higher risk of developing asbestosis if they have higher levels of exposure to asbestos dust over longer periods of time. The disease typically does not develop for 10 or 20 years after first exposure.
Crystalline silica is a main component of dust from sand and rock. Examples of workers who might be exposed to silica include miners, sandblasters, stonemasons and foundry workers. Risk factors for developing silicosis include higher levels of silica exposure and longer time of exposure. Lower levels of exposure over many years most commonly lead to "chronic simple silicosis" in which many small nodules of inflammation form in the lungs. This is the most common form of silicosis. In a small percentage of cases, simple silicosis develops in to a more severe form of silicosis called "progressive massive fibrosis" (PMF) when many small nodules "grow" together into large masses. In PMF, patients have more severe respiratory symptoms because the masses limit the function of normal lung. If exposure to silica is very intense over a shorter period of time, patients may develop "accelerated" or "acute silicosis." Acute silicosis is rare and generally occurs only after extremely high exposures, but it causes death in most cases.
Coal dust is made of carbon-containing particles, and coal miners are at risk of inhaling this dust. Coal miners may also be exposed to silica-containing dust because coal mining may involve some drilling into silica-containing rock. Workers exposed to graphite dust can also develop pneumoconiosis similar to CWP. Just like with silicosis, CWP is most commonly "simple" disease with nodules of inflammation forming in the lungs, but it can become PMF in a small percentage of patients.
Chronic beryllium disease (also called berylliosis) is another work-related lung disease that may be considered pneumoconiosis. Beryllium is a very strong and lightweight metal that is used in the electronics, aerospace and nuclear power industries. Chronic beryllium disease is caused by inhalation of airborne beryllium during its processing such as in melting or grinding it. There are other less common mineral dusts that might also cause pneumoconiosis including cobalt, talc and aluminum oxide.
When to See Your Doctor
If you have been exposed to asbestos, silica, coal dust or other toxic dusts and have respiratory symptoms such as cough or shortness of breath, you should consult your healthcare provider.
This content was developed in partnership with the CHEST Foundation, the philanthropic arm of the American College of Chest Physicians.