Asbestos is a natural mineral that has long been praised for its fire and heat resistant fibers, and its subsequent usefulness in construction and other industrial efforts. Mined for its various beneficial properties, asbestos possesses a great tensile strength, strong thermal and chemical stability, and an unmatched ability to insulate.
Asbestos comes in two forms, which are distinguished based on their crystalline structure. The first is the amphibole form, which consists of thin fibers that come together to form a chain structure. There are five types of amphibole asbestos that have been used commercially, which include crocidolite, amosite, anthophyllite, actinolite, and tremolite.
Crocidolite, or blue asbestos, is one of the more common types of amphibole asbestos present in buildings, along with amosite asbestos, which is also known as brown asbestos. Anthophyllite and tremolite asbestos account for less than one percent of the production and consumption, seeing rare commercial use. The U.S. Geological Survey (USGS ) explains that there are over 65 additional forms of chemically-distinct amphibole forms of asbestos that are not used commercially as asbestos.
The second variety of this mineral, serpentine asbestos, is thicker, shorter, and curlier than the amphibole form and is formed in layers. The name for this type of asbestos is chrysotile and the USGS explains about 96 percent of worldwide asbestos production and consumption between 1900 and 2003 is made up of this form. Its greater availability and more widely distributed natural deposits also led to its more common use than other forms of asbestos.
Why is Asbestos Hazardous?
When the fibers are disturbed, asbestos becomes airborne. Once they enter the air, they are capable of being inhaled by individuals in the area. Once they are introduced in the body, they can lead to numerous health conditions, as they can enter the lung tissue and the immune system is not capable of removing them.
When is Asbestos a Hazard?
Asbestos is believed to only be a significant hazard when it has become airborne. If asbestos is present, it should be monitored to ensure that the area is still safe and that the particles have not been disturbed. “Friable asbestos” is a term used to describe asbestos fibers which can be converted to dust when pressure is applied to them. Harder fibers which are not subject to pressure are known as “non-friable asbestos.” If the asbestos is “non-friable,” the mineral is not under regulation. However, these fibers are still able to be converted into “friable asbestos” through the use of grinding machines or sanding, making them a perennial threat.
Comparison of Amphibole and Chrysotile Asbestos
Chrysotile asbestos is believed by some to be the most dangerous form of asbestos, as it has long, thin fibers which scientists believe allows them to remain in the lung tissue better than the shorter fibers of amphibole forms. Although amphibole forms more easily penetrate lung tissue deeply, these fibers are also more easily expelled, the USGS explains.
Evidence also suggests that fiber solubility is the second biggest factor in the chance of disease development, behind fiber length. Chrysotile’s greater solubility allows it to be removed more rapidly from lung tissue than amphibole asbestos forms, lessening its threat. Along with the material’s ability to penetrate lung tissue, another important factor in the development of asbestos-related disease is the length of time the fiber resides in the body. As the material spends more time in these tissues, the chances of developing disease also increase, meaning the less soluble amphibole form of asbestos might be more dangerous.
Uses of Asbestos
There are several uses of asbestos, particularly in the realm of duct and pipe insulation, insulation in buildings, as well as in ceiling and wall panels. More specifically, the fibers can be found in compounds for patching and spackling, roofing materials, brake linings and pads, cement, heating appliances in the home such as toasters, flooring tiles, and furnaces. The USGS reports that as late as 2003, 4,650 tons of chrysotile asbestos was used in the United States. Of that asbestos, about 80 percent was used in asphalt roof coatings and sealants; five percent found use in other coatings and compounds; and the remaining amount was used in miscellaneous applications.
Because of these common asbestos uses, the most common victims of related diseases are mechanics, construction workers, and those who have worked in shipyards. In 1973, aerosols containing asbestos were prohibited. In the mid 1970s, other materials containing asbestos were banned. Although regulated, the use of asbestos continues in the U.S. today, despite the presence of many other developed nations who completely banned the material.
Who is at Risk for Asbestos Related Diseases?
Although scientists and doctors agree that those who undergo the longest, most intense asbestos exposure are at the greatest risk of developing a related disease, exposure at any quantity puts individuals at risk for asbestos-related conditions such as malignant mesothelioma. In fact, a large number of those with mesothelioma never experienced direct exposure to asbestos fibers. Even secondhand exposure to the fibers, through the clothes of those who work frequently with the mineral, can put individuals at risk for developing one of these conditions.