Asbestos is the name given to a group of six different fibrous minerals (amosite, chrysotile, crocidolite, and the fibrous varieties of tremolite, actinolite, and anthophyllite) that occur naturally in the environment. Asbestos minerals have separable long fibers that are strong and flexible enough to be spun and woven and are heat resistant. Because of these characteristics, asbestos has been used for a wide range of manufactured goods, mostly in building materials (roofing shingles, ceiling and floor tiles, paper products, and asbestos cement products), friction products (automobile clutch, brake, and transmission parts), heat-resistant fabrics, packaging, gaskets, and coatings. Some vermiculite or talc products products may contain asbestos.
How was asbestos used?
It has been estimated that asbestos was once used in more than 3,000 different products. Asbestos can be found in vinyl flooring, patching compounds and textured paints, sprayed acoustic ceilings, acoustic ceiling tiles, stove insulation, furnace insulation, pipe insulation, wall and ceiling insulation, roofing shingles and siding, home appliances, fireretardant clothing, vehicle brake pads, and cement pipe.
What happens to asbestos when it enters the environment?
Asbestos fibers can enter the air or water from the breakdown of natural deposits and manufactured asbestos products. Asbestos fibers do not evaporate into air or dissolve in water. Small diameter fibers and particles may remain suspended in the air for a long time and be carried long distances by wind or water before settling down. Larger diameter fibers and particles tend to settle more quickly.
Asbestos fibers are not able to move through soil. Asbestos fibers are generally not broken down to other compounds and will remain virtually unchanged over long periods.
How might I be exposed to asbestos?
We are all exposed to low levels of asbestos in the air we breathe. These levels range from 0.00001 to 0.0001 fibers per milliliter of air and generally are highest in cities and industrial areas.
People working in industries that make or use asbestos products or who are involved in asbestos mining may be exposed to high levels of asbestos. People living near these industries may also be exposed to high levels of asbestos in air.
Asbestos fibers may be released into the air by the disturbance of asbestos-containing material during product use, demolition work, building or home maintenance, repair, and remodeling. In general, exposure may occur only when the asbestos-containing material is disturbed in some way to release particles and fibers into the air.
Drinking water may contain asbestos from natural sources or from asbestos-containing cement pipes.
What are the health effects of asbestos?
You will not be harmed by touching asbestos or being near materials containing it. Asbestos can cause health problems when inhaled into the lungs. If products containing asbestos are disturbed, microscopic, lightweight asbestos fibers are released into the air. Persons breathing the air may breathe in the asbestos fibers. Continued exposure increases the amount of fibers that remain in the lung. Fibers embedded in lung tissue over time may result in lung diseases such as asbestosis, lung cancer, or mesothelioma. Studies have shown that the combination of smoking and asbestos exposure is particularly harmful.
How much asbestos is dangerous to my health?
There is no minimum concentration of asbestos fibers in the air that is considered safe for humans to inhale on a continual basis. The risk of developing adverse health effects is dependent upon the exposure (the amount of asbestos inhaled and the duration of time it was inhaled, typically measured in years) a person has had. Symptoms of lung problems do not usually appear until after 20-30 years of exposure to high levels of asbestos fibers (as might be found in an industrial setting). Most people do not develop health problems when exposed to small amounts of asbestos.
How can families reduce the risk of exposure to asbestos?
Materials containing asbestos that are not disturbed or deteriorated do not, in general, pose a health risk and can be left alone. If you suspect that you may be exposed to asbestos in your home, contact your state or local health department or the regional offices of EPA to find out how to test your home and how to locate a company that is trained to remove or contain the fibers.
Is there a medical test to show whether I’ve been exposed to asbestos?
Low levels of asbestos fibers can be measured in urine, feces, mucus, or lung washings of the general public. Higher than average levels of asbestos fibers in tissue can confirm exposure but not determine whether you will experience any health effects.
A thorough history, physical exam, and diagnostic tests are needed to evaluate asbestos-related disease. Chest x-rays are the best screening tool to identify lung changes resulting from asbestos exposure. Lung function tests and CAT scans also assist in the diagnosis of asbestos-related disease.
Environmental Protection Agency (EPA) views on asbestos
The following summarizes the five major facts that the EPA has presented in congressional testimony:
• Asbestos is hazardous and human risk of asbestos disease depends upon exposure.
• Prevailing asbestos levels in buildings – the levels school children and others face as building occupants – seem to be very low, based upon available data.
• Removal is often not a school district’s or other building owner’s best course of action to reduce asbestos exposure. In fact, an improper removal can create a dangerous situation when none previously existed.
• EPA only requires asbestos removal in order to prevent significant public exposure to asbestos, such as during building renovation or demolition.
• EPA recommends in-place management whenever asbestos is discovered. Instead of removal, a conscientious in-place management program will usually control fiber releases, particularly when the materials are not significantly damaged and are not likely to be disturbed.
• Use methods which minimize dust generation, e.g. hand powered tools, control dust generation by wetting the asbestos product, and avoid unnecessary breakage of asbestos-cement products.
• Wear respiratory protection suitable for asbestos dust, e.g. toxic dust respirator.
• Collect all debris and double wrap in plastic bags or sheeting that is at least 0.2 millimeters thick, seal with adhesive tape, and appropriately label before disposing by burial at approved disposal facilities.
• Shower thoroughly and wash work clothing after completion.
• Keep people who need not be present away from the work area.