Asbestos Exposure - The Primary Cause of Mesothelioma
Asbestos is a naturally occurring mineral with heat-resistant and insulating properties. People have been using asbestos for thousands of years. Asbestos has been used commercially in mining, construction, shipbuilding and the automotive industry for more than a century. It has been used to create fire-resistant products such as insulation, floor materials, ceiling tiles and automobile brake linings. Many new uses were found during World Wars I and II.
Three Main Types of Asbestos
Chrysotile Asbestos (white asbestos) was the form of asbestos used predominantly in products manufactured in the United States. Although small amounts of chrysotile were mined in the United States, the overwhelming majority of the asbestos was mined in Canada and then shipped into the United States. Chrysotile asbestos is also known as serpentine because it is found in serpentine rock.
Amosite Asbestos (gray asbestos) was used to a lesser extent than chrysotile asbestos. Most of the amosite asbestos used in the United States was mined in South Africa. Amosite asbestos is an amphibole.
Crocidolite Asbestos (blue asbestos) is the form of asbestos least used in commercial products. Crocidolite asbestos only accounts for approximately 10% of the asbestos used in the United States.
Asbestos Fibers
When asbestos fibers are released into the air, the fibers can be inhaled and swallowed. It is believed that the fibers cause illnesses by irritating cells (in the case of mesothelioma, the cells of the pleura or peritoneum). It wasn’t until the 1950s that a clear relationship between asbestos exposure and lung cancer was recognized; a relationship between asbestos and malignant mesothelioma wasn’t documented until 1960. People exposed to asbestos are at greater risk for lung cancer than mesothelioma. In addition, the risk for lung cancer is 60 to 90 fold greater in smokers exposed to asbestos than in nonsmokers with similar exposure levels. Asbestos exposure can also cause asbestosis (a chronic lung disease) and a number of other cancers.
Asbestos in the Workplace
Today, as many as 8 million Americans have had work-related asbestos exposure. People who work in any of the industries in which asbestos is used have an increased risk for all asbestos-related illnesses. In addition, family members of people with occupational exposure to asbestos have a small but significantly increased risk because the fibers can be carried on the clothing and hair of those exposed. Since 1972, people who work with asbestos are required to shower and change clothes before leaving the workplace.
Other Asbestos Fiber Exposure
Even people without these risk factors may have been exposed to asbestos, because asbestos-containing materials were used in the construction of many older buildings. When these materials deteriorate, asbestos fibers are released into the air. The danger occurs if the material containing asbestos deteriorates or is in some way disturbed (for example, by construction or demolition). If you live in an older home and plan a remodeling project, you may need to hire experts to safely remove or encapsulate any asbestos in your home. Incidence rates of malignant mesothelioma are expected to peak around the year 2000, as people who were exposed to asbestos in the 1950s and 1960s develop the disease (symptoms typically do not occur until 20 to 40 years after exposure). After the year 2000, the number of cases is expected to decline. Now that the dangers of asbestos are well understood, the use of asbestos declines each year, and industries that use asbestos have implemented safeguards against exposure. There is no known safe level of asbestos exposure. For this reason, everyone is advised to avoid any exposure.
