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August 29, 2001

Information on Asbestos, CAS#1332-21-4

By Maureen Alvarez
CIH, CSP

Between 1940 and 1980, an estimated 27 million Americans workers had an occupational exposure to asbestos that could result in health effects.  The Department of Health and Human Services (DHHS) has determined that asbestos is a known carcinogen.  So, what is asbestos?  What are the health effects?  Am I at risk?

What is Asbestos?

Asbestos is a naturally occurring mineral found in soil and rock in some areas of the United States.  The six types of asbestos are actinolite, amosite, anthophyllite, chrysotile, crocidolite, and tremolite.  These minerals are made up of fibers that vary in size and shape. 

Asbestos fibers are resistant to heat and most chemicals.  Because of this, asbestos fibers are used for a wide range of manufactured goods, mostly roofing shingles, insulation material, ceiling and floor tiles, paper products, asbestos cement products, friction products (automobile clutch, brake, and transmission parts), textiles, packaging, gaskets, and coatings.

How would I be exposed to asbestos?

Inhalation of asbestos fibers is the method of exposure that is most likely to cause adverse health effects for people.  Workers in industries that use asbestos or products containing asbestos (such as building materials), may inhale fibers that are suspended in the air.  Workers may also carry asbestos fibers home on their clothes, where family members might come into contact with asbestos by inhaling the fibers.  Also, people who live or work near asbestos-related operations may inhale asbestos fibers that enter the air because of releases of materials into the environment.  Generally, asbestos fibers are thin fibers too small to be seen; as they float in the air, they can easily be inhaled.  People may also swallow asbestos fibers if they eat in areas where asbestos fibers are in the air or if they drink water contaminated with fibers.  Homes and businesses insulated with material containing asbestos may also be a source of exposure.

What recommendations has the federal government made to protect human health?

The federal government has taken a number of steps to protect citizens from exposure to asbestos.  First, on July 12, 1989, the EPA established a ban on new uses of asbestos.  Uses established before this date are still allowable.  Second, EPA has established regulations that require school systems to inspect for asbestos and, if damaged asbestos is found, to eliminate or reduce the exposure, either by removing the asbestos or by covering it up so it cannot get into the air.  In addition, EPA provides guidance and support for reducing asbestos exposure in other public buildings.  Third, EPA regulates the release of asbestos from factories and during building demolition or renovation to prevent asbestos from getting into the environment.  The EPA also regulates the disposal of waste asbestos materials or products, requiring these to be placed only in approved locations.  Fourth, EPA has proposed a limit of 7 MFL (million fibers per liter), the concentration of long fibers that may be present in drinking water.  Fifth, the Food and Drug Administration (FDA) regulates the use of asbestos in the preparation of drugs and restricts the use of asbestos in food-packaging materials.

The National Institute for Occupational Safety and Health (NIOSH) has recommended that inhalation exposures not exceed 0.1 f/cc.  The Occupational Safety and Health Administration (OSHA) has established an enforceable limit of 0.1 f/cc on the average 8-hour daily concentration of asbestos allowed in air in the workplace.

Does asbestos exposure cause health problems?

Health problems are usually related to the amount and length of time of exposure to asbestos.  After asbestos fibers are inhaled they can easily enter and become trapped in the airways and lung tissue and the body has difficulty removing the fibers.  Continued exposure to asbestos increases the amount of asbestos that remains in the lungs.  Diseases related to asbestos may not show up until several years later.

It is known that asbestos causes cancer in people. There are two types of cancer caused by exposure to high levels of asbestos: cancer of the lung tissue itself and mesothelioma, a cancer of the membrane that surrounds the lung and other internal organs. Both of these are usually fatal.  These diseases don’t develop immediately, but show up only after many years.

Interactions between cigarette smoke and asbestos increase your chances of getting lung cancer.  Studies of workers suggest that breathing asbestos can increase the chances of getting cancer in other parts of the body (stomach, intestines, esophagus, pancreas, kidneys), but this is not certain.

People who are exposed to lower levels of asbestos may also have an increased risk of developing cancer, but the risks are usually small and are difficult to measure.

It is not known whether ingesting asbestos causes cancer.  Some people who had been exposed to asbestos fibers in their drinking water had higher-than-average death rates from cancer of the esophagus, stomach, and intestines.  However, it isn't known whether this was caused by asbestos or by something else.

What illnesses are associated with asbestos exposure?

Asbestosis

Information on the health effects of asbestos in people comes mostly from studies of people who were exposed in the past to high levels of asbestos in the workplace.  Workers who breathe in asbestos may develop a slow buildup of scar-like tissue in the lungs and in the membrane that surrounds the lungs.  This scar-like tissue does not expand and contract like normal lung tissue and so breathing becomes difficult.  Blood flow to the lung may also be decreased and this causes the heart to enlarge.  This disease is called asbestosis.

Asbestosis is a serious, progressive, long-term disease of the lungs.  It is not cancer.  It is caused by inhaling asbestos fibers that irritate lung tissues and cause the tissues to scar.  The scarring makes it hard for lungs to do their job of getting oxygen into the blood.  Symptoms of asbestosis include shortness of breath and a dry crackling sound in the lungs while inhaling.  The chance of getting asbestosis is very small for those who do not work with asbestos.  Although there is no effective treatment for asbestosis, symptoms of the disease can be managed under the care of a physician.  The disease, if severe, can cause disability and death.

Lung Cancer

Lung cancer causes the largest number of deaths related to asbestos exposure.  People who work in occupations involving the mining, milling, manufacturing, and use of asbestos and its products are more likely to get lung cancer than the general population.  The most common symptoms of lung cancer are coughing and a change in breathing.  Other symptoms include shortness of breath, persistent chest pain, hoarseness, and anemia.  People who develop these symptoms do not necessarily have lung cancer, but should consult a physician for advice.  People who have been exposed to asbestos and are also exposed to some other cancer-causing product, such as cigarette smoke, have a greater risk of developing lung cancer than people who have been exposed only to asbestos.

Mesothelioma

Asbestos workers have increased chances of getting two types of cancer: cancer of the lung tissue itself and mesothelioma, a cancer of the thin membrane that surrounds the lung and other internal organs.  Lung cancer is usually fatal, while mesothelioma is invariably fatal within a few months of diagnosis.  These diseases do not develop immediately, but appear only after a number of years.

Mesothelioma is a relatively rare form of cancer that is found in the thin lining (membrane) of the lungs, chest, abdomen, and heart.  Several hundred cases are diagnosed each year in the United States, and most cases are linked with exposure to asbestos.  About 2 percent of all miners and textile workers who work with asbestos, and 10 percent of all workers who were involved in the manufacture of gas masks containing asbestos, develop mesothelioma.  This disease may not show up until many years (generally 20 to 40 years or more) after asbestos exposure.

Is there a medical test to show whether I've been exposed to asbestos?

Chest x-rays cannot show asbestos fibers, but can find early signs of lung disease.  Other tests, such as lung function tests and high resolution CT scans, can also detect changes in the lungs caused by asbestos.  These changes usually are not detectable until years after exposure.

Additional Information

The Consumer Product Safety Commission (CPSC) is responsible for the regulation of asbestos in consumer products. The CPSC maintains a toll-free information line on the potential hazards of commercial products; the telephone number is 1–800–638–2772. In addition, CPSC provides information about laboratories for asbestos testing, guidelines for repairing and removing asbestos, and general information about asbestos in the home. Publications are available from the Office of Public Affairs, Consumer Product Safety Commission, 4330 East-West Highway, Bethesda, MD 20816; the telephone number is 301–504–0580.

The U.S. Food and Drug Administration is concerned with asbestos contamination of foods, drugs, and cosmetics and will answer questions on these topics. The address is Office of Consumer Affairs, Food and Drug Administration, HFE–88, 5600 Fishers Lane, Rockville, MD 20857; the telephone number is 301–443–3170.

Also, please check out these Internet links for information regarding asbestos.

 http://www.cdc.gov/niosh/asbestos.html

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