What is asbestos exposure?
Asbestos is a naturally occurring mineral fiber whose fire-resistant properties have been known since antiquity. Although there are a variety of forms of asbestos, with some being more associated with occupational illness and disease than others, all asbestos shares a common characteristic: Because asbestos consists of silica crystals, the fibers are inherently irritating to human tissue. On the surface of the skin, they can become embedded and lead to the formation of calluslike growths, termed “asbestos warts,” as the body attempts to encapsulate the irritating fibers.
Inhaled or ingested asbestos fibers are a more serious matter. Asbestos exposure has been associated with cancers of the stomach, liver, and other organs, but asbestosis and mesothelioma are the two most common asbestos-related health disorders.
Asbestosis, a lung disorder caused by fiber-related scarring of lung tissue, was one of the first disorders recognized as being associated with asbestos exposure. It is now known that the fibers do not scar the lungs directly; rather, they trigger the production of acid by the lung tissue as the body attempts to break down the silica crystals. Asbestosis is similar to disorders such as silicosis, “brown lung,” and “black lung” in that lung capacity is reduced as cumulative damage reduces victims’ ability to breathe.
Mesothelioma, a particularly invidious cancer, is also associated with asbestos exposure. With this form of cancer, the cells between the walls of the pleura (the outer covering of the lungs that separates the lungs from the chest wall) or the peritoneum (the sac containing the abdominal organs) form malignant growths.
Both asbestosis and mesothelioma may take many years to develop, with some victims not developing mesothelioma until as many as forty years after the initial exposure. On the other hand, there have been cases of adolescents developing mesothelioma within only a few months of initial asbestos exposure.
Localized “asbestos warts” on the skin may be unattractive, but they are generally benign. The lung diseases associated with asbestos exposure, however, are progressive and ultimately fatal. In asbestosis, the scarred lung tissue becomes increasingly stiff, and the person becomes unable to take in sufficient oxygen.
Mesothelioma has a high mortality rate, as it is rarely detected in its early stages. Symptoms such as shortness of breath are attributed to more common diseases such as asthma. As the cancer spreads, lung capacity is diminished, and the victim eventually dies from the inability to take in sufficient oxygen, if he or she has not already succumbed to other organs failing after the cancer metastasizes.
The ancient Romans mined asbestos for use in manufacturing fireproof mats and garments, as did various other cultures throughout recorded history. During the nineteenth century, asbestos became a popular material for lamp wicks, as it could convey the lamp oil without being consumed by the flame itself. As industrialization progressed, asbestos became widely used in such applications as brake shoes for automobiles, oven linings in electric stoves, and building materials. Asbestos was impregnated into siding and shingles for exterior walls and roofs, insulation for attics and walls, and ceiling and floor tiles. By the mid-twentieth century, asbestos had become ubiquitous in society, from the materials on which people walked to the roofs over their heads. The Romans recognized that mining asbestos was effectively a death sentence, as slaves working in asbestos production quickly developed coughs and wasted away from lung diseases. As mining was generally a dusty and dangerous occupation, however, the special risks that asbestos presented were not well recognized. For centuries, many physicians assumed that all miners’ lung ailments were forms of consumption (tuberculosis), when in fact tuberculosis was an opportunistic infection that followed after a miner became weakened by disorders such as silicosis and asbestosis.
By the 1930s, researchers had established that asbestos presented especially high risks of causing lung diseases in miners, shipyard workers, and others who either manufactured or worked with materials incorporating asbestos, such as insulation. By the mid-twentieth century, it had become evident that extremely small amounts of asbestos exposure could lead to asbestos-related disorders. Miners’ spouses developed mesothelioma after being exposed to asbestos through doing laundry, for example, while children became victims through exposure to their parents’ work clothes in the home.
The widespread use of asbestos fibers in multiple applications means that exposure remains a concern in the twenty-first century. Although asbestos is no longer as widely used in industry, reducing the prevalence of workplace exposures, people can still risk asbestos exposure when engaging in home improvement projects as they rip out old flooring or replace ceiling tile.
"Asbestos." American Cancer Society, May 10, 2013.
"Asbestos." MedlinePlus, June 17, 2013.
Bowker, Michael. Fatal Deception: The Terrifying True Story of How Asbestos Is Killing America. New York: Touchstone, 2003..
Frank, A. L. “Global Problems from Exposure to Asbestos.” Environmental Health Perspectives Supplements 101, no. 3 (1993): 165–68.
National Heart, Lung, and Blood Institute. "What Are Asbestos-Related Lung Diseases?" National Institutes of Health, May 1, 2011.
Roggli, Victor L., et al. Pathology of Asbestos-Associated Diseases. 2d ed. New York: Springer, 2004.