"Asbestos" is the name given to a group of minerals that occur naturally as bundles of fibers which can be separated into thin threads. These fibers are not affected by heat or chemicals and do not conduct electricity. For these reasons, asbestos has been widely used in many industries.
Four types of asbestos have been used commercially:
- Chrysotile (or white asbestos)
- Crocidolite (or blue asbestos)
- Amosite (usually has brown fibers)
- Anthophyllite (usually has gray fibers).
Chrysotile asbestos, with its curly fibers, is in the serpentine family of minerals. The other types (which all have rod-like fibers) are known as amphiboles.
Asbestos fiber masses tend to break easily into a dust composed of tiny particles that can float in the air and stick to clothes. The fibers may be easily inhaled or swallowed and can cause serious health problems, such as
lung cancer.
Asbestos was mined and used commercially in North America beginning in the late 1800s. Its use increased greatly during World War II; since then, it has been used in many industries. For example:
- The building and construction industry has used asbestos for strengthening cement and plastics as well as for insulation, fireproofing, and sound absorption.
- The shipbuilding industry has used it to insulate boilers, steam pipes, and hot water pipes.
- The automotive industry uses it in vehicle brake shoes and clutch pads.
More than 5,000 products contain or have contained asbestos.
Government regulations and other actions, coupled with widespread public concern about the hazards of asbestos, have resulted in a significant annual decline in U.S. use of asbestos. Domestic consumption amounted to about 719,000 metric tons in 1973, but it had dropped to about 9,000 metric tons by 2002. Asbestos is currently used most frequently in gaskets and in roofing and friction products.
Health Risks Associated With Exposure
Exposure to asbestos may increase the risk of several serious diseases, including:
- Asbestosis -- a chronic lung ailment that can produce shortness of breath, coughing, and permanent lung damage
- Lung cancer
- Mesothelioma -- a relatively rare cancer of the thin membranes that line the chest and abdomen
- Other cancers, such as those of the larynx, oropharynx, gastrointestinal tract, and kidney.
Who Is at Risk for Asbestos-Related Health Problems?
Nearly everyone is exposed to asbestos at some time during their life. However, most people do not become ill from their exposure. People who become ill from it are usually those who are exposed to it on a regular basis, most often in a job where they work directly with the material or through substantial environmental contact.
Since the early 1940s, millions of American workers have been exposed to asbestos. Health hazards from asbestos fibers have been recognized in workers exposed in a variety of occupations, such as:
- Shipbuilding trades
- Asbestos mining and milling
- Manufacturing of asbestos textiles and other asbestos products
- Insulation work in the construction and building trades
- Brake repair.
Demolition workers, drywall removers, and firefighters also may be exposed to asbestos fibers.
As a result of government regulations and improved work practices, today's workers (those without previous exposure) are likely to face smaller risks than did those exposed in the past. Although it is known that the risk to workers increases with heavier exposure and longer exposure time, investigators have found asbestos-related diseases in individuals with only brief exposures. Generally, those who develop asbestos-related diseases show no signs of illness for a long time after their first exposure. It can take from 10 to 40 years for symptoms of an asbestos-related condition to appear.
There is some evidence that family members of workers heavily exposed to asbestos face an increased risk of developing mesothelioma. This risk is thought to result from exposure to asbestos fibers brought into the home on the shoes, clothing, skin, and hair of workers. This type of exposure is called paraoccupational exposure. To decrease these exposures, people exposed to it at work are required to shower and change their clothing before leaving the workplace.
Not all workers exposed to asbestos will develop diseases related to their exposure. The risk of developing asbestos-related diseases varies with the type of industry in which the exposure occurred and with the extent of the exposure. Asbestos that is bonded into finished products, such as walls and tiles, poses no risk to health as long as it is not damaged or disturbed (for example, by sawing or drilling) in such a way as to release fibers into the air. When asbestos fibers are set free and inhaled, however, exposed individuals are at risk of developing an asbestos-related disease.
In addition, different types of asbestos fibers may be associated with different health risks. For example, results of several studies suggest that amphibole forms of asbestos may be more harmful than chrysotile, particularly for
mesothelioma. Even so, no fiber type can be considered harmless, and people working with asbestos should always take proper safety precautions to limit exposure.
Risks of Asbestos Exposure and Smoking
Many studies have shown that the combination of smoking and asbestos exposure is particularly hazardous. Smokers who are also exposed to this material have a greatly increased risk of
lung cancer. However, smoking combined with asbestos exposure does not appear to increase the risk of mesothelioma.
There is evidence that quitting smoking will reduce the risk of lung cancer among asbestos-exposed workers. People who were exposed to asbestos on the job at any time during their life (or who suspect they may have been exposed) should not smoke. If they smoke, they should stop.
Who Needs to Be Examined for Asbestos Exposure?
Individuals who have been exposed (or suspect they have been exposed) to asbestos fibers on the job or at home via a family contact should inform their physician of their exposure history and any symptoms.
Asbestos fibers can be measured in urine, feces, mucus, or material rinsed out of the lungs. A thorough physical examination, including a chest x-ray and lung function tests, may be recommended. It is important to note that chest x-rays cannot detect asbestos fibers in the lungs, but they can help identify any lung changes resulting from asbestos exposure.
Interpretation of the chest x-ray may require the help of a specialist who is experienced in reading x-rays for asbestos-related diseases. Other tests also may be necessary.
As noted earlier, the symptoms of asbestos-related diseases may not become apparent for many decades after exposure. If any of the following symptoms develop, a physical examination should be scheduled without delay:
- Shortness of breath
- A cough or a change in cough pattern
- Blood in the sputum (fluid) coughed up from the lungs
- Pain in the chest or abdomen
- Difficulty in swallowing or prolonged hoarseness
- Significant weight loss.
Limiting Asbestos Exposure in the Workplace
Employers are required to follow regulations dealing with asbestos exposure on the job that have been issued by the Occupational Safety and Health Administration (OSHA), the federal agency responsible for health and safety regulations in maritime, construction, manufacturing, and service workplaces. The Mine Safety and Health Administration (MSHA) enforces regulations related to mine safety.
Workers should use all protective equipment provided by their employers and follow recommended work practices and safety procedures. For example, National Institute of Occupational Safety and Health (NIOSH)-approved respirators that fit properly should be worn by workers when required.
Workers who are concerned about asbestos exposure in the workplace should discuss the situation with other employees, their employee health and safety representative, and their employers.
Risk of Non-Occupational Exposure to Asbestos
The material is so widely used that the entire population has been exposed to some degree. Air, drinking water, and a variety of consumer products all may contain small amounts of asbestos. In addition, asbestos fibers are released into the environment from natural deposits in the earth and as a result of wear and deterioration of asbestos products. Disease is unlikely to result from a single, high-level exposure, or from a short period of exposure to lower levels of asbestos.
Government and Insurance Coverage for Asbestos-Related Illness
Medical services related to asbestos exposure may be available through the government for certain groups of eligible individuals. In general, individuals must pay for their own medical services unless they are covered by private or government health insurance. Some people with symptoms of asbestos-related illness may be eligible for Medicare coverage.
People with asbestos-related diseases may also qualify for financial help, including medical payments, under state workers' compensation laws. Because eligibility requirements vary from state to state, workers should contact the workers' compensation program in their state. Contact information for the workers' compensation program in each state may be found in the blue pages of a local telephone directory.
If exposure occurred during employment with a federal agency (military or civilian), medical expenses and other compensation may be covered by the Federal Employees' Compensation Program. Workers who are or were employed in a shipyard by a private employer may be covered under the Longshoremen and Harbor Workers' Compensation Act.
Workers may wish to contact their international union for information on other sources of medical help and insurance matters.
Eligible veterans and their dependents may receive healthcare at a Department of Veterans Affairs (VA) Medical Center. Treatment for service-connected and nonservice-connected conditions is provided. If the VA cannot provide the necessary medical care, they will arrange for enrolled veterans to receive care in their community.
The following is a summary of key points about asbestos:
- "Asbestos" is the name given to a group of minerals that occur naturally as bundles of fibers
- Smokers who are also exposed to asbestos have a greatly increased risk of lung cancer
- Individuals who have been exposed (or suspect they have been exposed) to asbestos fibers on the job or at home via a family contact should inform their physician of their exposure history and any symptoms
- Government agencies can provide additional information on asbestos exposure.
