Pneumoconiosis, coming from the Greek pneuma (air or wind) and konis (dust), is a condition caused by the inhalation (usually over long periods of time) of organic or inorganic "dust" (sometimes chemical irritants). It is a general term for a number of diseases of the lung that are caused by this inhalation of dust.
Over time, the particles in the lungs (lodged in the alveoli) may lead to inflammation and then progress into scarification and fibrosis as the body reacts to the foreign matter. This can lead to decreased lung capacity with the correlated effect of poor stamina and easy exhaustion because of the diminished ability of the lungs to exchange oxygen and carbon dioxide properly. In later stages (if it progresses), the fibrosis can stiffen the lungs and even lead to death.
Early symptoms can include: coughing (often dry but not always), wheezing, shortness of breath (particularly during physical exertion), and some tightness in the chest. It can lead to chronic bronchitis and emphysema and increased potential for other respiratory diseases such as pneumonia. In the past, people who suffered from forms of pneumoconiosis—particularly black lung and silicosis—were highly susceptible to tuberculosis (something that has become less common due to vaccines and better methods of treatment). Those with severe fibrosis can have great difficulty breathing and their lips and fingernails may appear bluish.
While smoking makes symptoms worse, it hasn't been shown to increase the possibility of getting a form of pneumoconiosis.
Pneumoconiosis is almost exclusively an occupational disease—and occupational lung diseases are the number one cause of work-related illness in the United States. While there is little treatment, other than bronchodilators to help open the passages as much as possible, and the progress is irreversible (some have suggested measures such as lung transplants for possible terminally-bound cases), the condition is preventable. Sadly, the things needed to help prevent it have not always been in place or are felt to be second place or minor to other concerns (productivity and economics). Still, there is a steady decline in the number of cases and deaths due to pneumoconiosis. There will probably always be cases and many of them will have been preventable.
In the twenty-five years between 1968 and 1992, 100,890 US residents over age fifteen died of some form of pneumoconiosis (Centers for Disease Control and Prevention). The peak year for deaths was 1972, with more than 5000. It declined as low as 3,230 in the last year of the study (1992). Mining has the two highest mortality ratios of pneumoconiosis (three of the five highest, overall). Ship building/repair, construction, and certain manufacturing industries also have significant numbers of cases.
Types of pneumoconiosis:
(statistics from the CDC study and the American Lung Association and are for the United States)
Asbestosis Caused by the prolonged inhalation of asbestos fibers. The fibers are silicates (see silicosis, below). People effected are those in construction, mining, and manufacture of insulation and fireproofing. Others include those that live around factories and mines producing asbestos-related products. It generally takes about ten years exposure to develop it but symptoms may not occur until many years later (ship workers exposed during World War Two didn't show symptoms until the 1960s and 1970s).
Extra taxation on the heart can lead to cardiac problems and exposure also leads to increased instances of lung cancer, particularly mesothelioma (which doesn't typically take as much exposure or time). Asbestosis accounted for 10% of the deaths, including 3,922 between 1979 and 1996. Instances will probably drop over time as many industries and countries have banned the use of asbestos because of its inherent danger.
Bagassosis A condition, similar to asthma, that develops from inhalation of the fungus spores from sugar cane (see hypersensitivity pneumonitis, below). It usually takes several months exposure and occurs hours after working with the plant. Repeated instances can lead to scarring of the lung tissue and pneumoconiosis.
Berylliosis Caused by prolonged inhalation of beryllium (sometimes exposure only affects the skin). The acute form of the disease is usually found in those working with the ore or the manufacture of alloys. This form is generally short-lived, given protection from exposure and time (massive exposure can lead to serious inflammation of the lung and death within seventy-two hours). It can develop into the chronic form, which takes place over a much longer time, and is found in scientific and industrial workers exposed to fumes and dust. It may not appear until as many as fifteen years after exposure. The later the appearance, the milder the symptoms.
Byssinosis Also know as "brown lung," byssinosis is caused by inhaling dust from cotton or other fibers (including hemp and flax). Also, in the case of cotton, known as "cotton-dust asthma" and "cotton-mill fever." Mostly found in textile workers, it has been recognized since the seventeenth century. Early occurrence or limited exposure can be cleared up by removal from the environment. Advanced stages are irreversible. A small number of deaths from byssinosis occur (less than twenty annually) with only 120 between 1979 and 1996. An estimated 35,000 textile workers (current and former) have been disabled due to it.
Coal Worker's Pneumoconiosis Better known as "black lung" (and the best known form of pneumoconiosis) because of the "distinctive blue-black marbling of the lung" (www.britannica.com) from the dust accumulation. The disease was first recognized in coal miners during the sixteenth century. It occurs most in those who mine hard coal (anthracite) but occurs among those mining soft coals and graphite, as well. It usually takes about ten to twenty years of exposure for symptoms to set in and it may be aggravated by silica (see silicosis, below) mixed with the coal.
A serious problem in the past when there were next to no safety constraints and workers would be directly exposed to the dust for long hours at a time—for example, people working in the coal breaker (often boys), a machine that breaks the coal up into small chunks for transport and use, who had to hover over a conveyor belt during the process. While coal mining has grown safer over the years, black lung is still a major health concern. Over 60% of the deaths over the twenty-five year span came from black lung, with 14,156 attributed between 1979 and 1996 (it is less than 2000 a year, currently). It is estimated that about 4.5% of workers are affected and around 0.2% have progressed to scarring.
In the 1968 to 1992 study, nearly two-thirds of the deaths occurred in workers from Pennsylvania.
Hypersensitivity Pneumonitis A condition caused by inhaling organic particles (as in bagassosis, above), specifically fungus spores. This can come from a number of sources, including but not limited to moldy hay and bird droppings. Prolonged exposure can lead to pneumoconiosis.
Kaolin pneumoconiosis Kaolin, "China clay," is an ingredient in the making of "ceramics, paper, medicines, cosmetics, and toothpaste" (www.intelihealth.com). It may occur in those who work with, mine, mill or bag it. Though X-rays may show significant changes in the lungs, severe cases as with other forms of pneumoconiosis are rare. [My grandmother spent some years making ceramics as a hobby but had to quit because of the way the dust affected her.]
Silicosis Silica is silicon dioxide, making up 59% of the mass of the earth's crust and 95% of known rocks. Silicosis occurs most often in "miners, quarry workers, stonecutters, tunnelers, and workers whose jobs involve grinding, sandblasting, polishing, and buffing" (www.britannica.com). It was recognized in the eighteenth century in knife grinders and potters and remains one of the most common forms of pneumoconiosis.
Once in the lungs, cells called macrophages, whose job it is to ingest and destroy foreign matter as well as release chemicals to attract white blood cells, attempt to deal with the silica. They are unable to and it results in the death of the cells. The dead cells begin to accumulate into nodules of fibrous tissue forming larger and larger masses as time and exposure go on. The fibrous tissue can additionally spread to the area of the heart and lymph nodes.
Silicosis makes up about 15% of deaths in the CDC study. The rate was as high as 1000 a year in 1971 and has stabilized at around 300 since the mid 1980s. Between 1979 and 1996, 2,694 people died as a result of the condition. It is estimated that around 1.6 million workers have had significant exposure to the dust and about 60,000 have silicosis to some extent.
Siderosis of the Lung Caused by inhalation of iron particles (also called "welder's lung" and "silver polisher's lung"). X-rays will reveal changes in the lungs but both symptoms and respiratory problems are quite rare.
Other Pneumoconioses These include barium sulfate, tin oxide, compounds made with (among others) cobalt and tungsten carbide, and numerous other mineral dusts. Most of these are far less common. According to the CDC, other forms (meaning other than asbestosis, black lung, byssinosis, and silicosis) made up about 18% of the deaths in the study.
Chemicals Some chemicals, such as sulfur dioxide, ammonia, acid, and chloride (chemicals that can be quickly absorbed by the lung tissue), can cause scarification as with pneumoconiosis. They may also cause fluid to accumulate in the lungs. Removal from exposure (also dependent on the amount of exposure) can often lead to recovery (even completely). Sometimes chronic bronchitis will remain as evidence of the exposure.
(Sources: www.britannica.com, www.intelihealth.com/IH/ihtIH/WSIHW000/9339/25658.html, www.cdc.gov/niosh/w7_high.html, www.lungusa.org/diseases/occupational_factsheet.html, www.rush.edu/worldbook/articles/002000a/002000089.html