Asbestos Information
Asbestos is the name given to a group of naturally occurring fibrous minerals found and mined worldwide. There are different varieties of asbestos, distinguished from each other by the size, shape, and strength of the fibers. The fiber most commonly used in commercial applications is fiber of the “chrysotile” variety. Chrysotile asbestos fibers are like little corkscrews instead of having a straight shape. The fibers adhere together in fiber bundles. Because of its fibrous nature, asbestos “shreds” into microscopic particles that remain in the area when larger particles of dust and debris have been swept away.
Asbestos has the properties of being both malleable and heat-resistant, making it excellent for a number of uses. The fibers can be spun and woven into thread or cloth, and writings from the ancient Romans tell of it being woven into candlewicks so that lamps could burn with an inexhaustible flame. Pliny the Elder also observed the high rate of lung disease and death for people who mined the asbestos or wove it into cloth.
In the modern era, asbestos was commonly added to insulation for pipes and boilers, to drywall and joint compound, to gaskets and packing for valves and pumps, to fireproofing spray in buildings, to cement, to brake linings, to vinyl linoleum, and to other products used in construction of buildings. It has excellent filtering properties and has been used in various different liquid and air filters. Asbestos has been used in making molds for dental crowns. Appliances (including televisions, stoves, and hair dryers) and other electrical equipment used asbestos paper to insulate hot areas or asbestos insulation to protect the wires. Asbestos cloth has been used to make “fireproof” curtains for theaters and clothing for firefighters, and to protect welders from sparks. The miners of the asbestos fibers and the people in the factories who manufactured the asbestos-containing products may have been the most heavily exposed of all workers, but they were not the only ones.
One of the widest uses of asbestos was in insulation aboard ships. Asbestos parts were used not only as components in the ship’s machinery, such as in packing for the pumps or firebrick materials for the boilers, but also to cover the steam lines throughout the ship. Steamlines ran throughout eating and sleeping quarters and other work spaces aboard ships, so even persons who never went into the machinery rooms were exposed to asbestos from the insulated pipes. There are many anecdotes of military seamen being in their bunk when the guns were fired on the ship; the shaking from the guns caused dust to fall on the sailors from the insulated steamlines. The states with the highest rates of malignant mesothelioma or other asbestos-related diseases are the states where shipbuilding and ship repair were large industries during and after World War II.
Another significant source of exposure to asbestos is schools. Because of concerns about keeping children safe from fires, asbestos materials were frequently used in the construction of schools. Students and teachers were then exposed when later construction or remodeling disturbed the existing asbestos materials. Further, asbestos fibers do not disappear or disintegrate on their own, and they are recirculated through movement and activity. Once asbestos is in the air in a closed environment, it is difficult to remove it.
A third prominent areas in which asbestos products have been used is in construction and remodeling, including work on residential and commercial buildings. Persons working in construction are frequently exposed to asbestos through the activities of other tradespeople performing work in the same area. For example, if a drywaller sands downs the area where he has applied joint compound that contained asbestos, the asbestos fibers in the joint compound are released into the air and can be inhaled by a carpenter working with just wood and nails in the same vicinity. Sheet metal workers might scrape off fireproofing spray previously applied to a girder in order to do their own work, and thereby disturb the asbestos fibers in the fireproofing.
Another group of people frequently exposed to asbestos products are those worked in the maintenance mechanic trade and related occupations, such as millwrights or machinists. They are exposed through removal of insulation surrounding pumps or boilers, through removal of gaskets and valve packing in the pumps or machinery, and through the insulation on the steam lines coming from the boilers. Again, if a team of insulators or pipe-fitters comes in to do repairs to a damaged line and removes asbestos-containing insulation from the pipes, the people responsible for maintaining the machinery would be exposed to asbestos fibers through that work as well as through their own.
Asbestos has also been commonly used in brake shoes and lining (for automobiles but also for locomotives and for clutches on other machinery). Although it is commonly believed that asbestos was made illegal in the late 1970’s, many uses are still legal in the United States. A NIOSH study in 1989 stated that asbestos was still a component in a majority of brakes. The study estimated that 155,000 mechanics and automotive garage workers could be potentially exposed to asbestos contained in brakes. Asbestos brake pads have not been banned by the EPA, nor has the import of asbestos-containing materials from some of the other countries that continue to manufacture them. Exposure to asbestos friction materials still presents a hazard to mechanics working in the present day.
While exposure to asbestos is primarily an occupational hazard, asbestos did not stay out of the home. People have been exposed to asbestos through any repair or remodeling work done on their home, and disclosure of asbestos materials is still required when selling a house. The families of people who worked in trades where they were exposed to asbestos were also frequently exposed through contact with the worker. Children hugged their father when he came home from work and breathed in the asbestos dust on his clothing. Women shook out and washed their husband’s dirty work clothes daily. Shipyard workers and insulators would bring home pieces of asbestos cloth, valued in the home for its absorbency and softness. Asbestos fibers remained in the worker’s car. Illustrating the unpredictability of asbestos-related diseases, sometimes the person who worked with the asbestos products never develops a serious illness while a family member contracts malignant mesothelioma.
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