As per the National Cancer Institute:
What is asbestos?
Asbestos is the name given to a group of minerals that occur naturally in the environment as bundles of fibers and can be separated into thin, durable threads. These fibers are resistant to heat, fire, and chemicals and do not conduct electricity. For these reasons, asbestos has been widely used in many industries.
There are two subgroups of asbestos: chrysotile, which has curly fibers and is in the serpentine family of minerals; and amphibole asbestos, which has straight, needle-like fibers and includes actinolite, tremolite, anthophyllite, crocidolite, and amosite asbestos. Chrysotile asbestos is the form that has been used predominantly in commercial applications worldwide (1, 2).
How is asbestos used?
Asbestos was mined and used commercially in North America beginning in the late 1800s. Its use increased greatly during World War II (3, 4). Since then, asbestos has been used in many industries. For example, the building and construction industry has used it for strengthening cement and plastics as well as for insulation, roofing, fireproofing, and sound absorption. The shipbuilding industry has used asbestos to insulate boilers, steampipes, and hot water pipes. The automotive industry uses asbestos in vehicle brakeshoes and clutch pads. Asbestos has also been used in ceiling and floor tile; paints, coatings, and adhesives; and plastics. In addition, asbestos has been found in vermiculite-containing consumer garden products and some talc-containing crayons.
In the late 1970s, the U.S. Consumer Product Safety Commission (CPSC) banned the use of asbestos in wallboard patching compounds and gas fireplaces because the asbestos fibers in these products could be released into the environment during use. Additionally, in 1979, manufacturers of electric hairdryers voluntarily stopped using asbestos in their products. In 1989, the U.S. Environmental Protection Agency (EPA) banned all new uses of asbestos; uses established prior to 1989 are still allowed. The EPA also established regulations that require school systems to inspect for damaged asbestos and to eliminate or reduce the exposure to occupants by removing the asbestos or encasing it (2).
In June 2000, the CPSC concluded that the risk of children’s exposure to asbestos fibers in crayons was extremely low (1). However, the U.S. manufacturers of these crayons agreed to eliminate talc from their products. In August 2000, the EPA responded to reports it received about the adverse human health effects associated with exposure to asbestos-contaminated vermiculite by conducting a series of tests to evaluate the extent of the risk. The EPA investigation concluded that the potential exposure to asbestos from some vermiculite products poses only a minimal health risk to consumers. The EPA recommended that consumers reduce the low risk associated with the occasional use of vermiculite during gardening activities by limiting the amount of dust produced during use. Specifically, the EPA suggested that consumers use vermiculite outdoors or in a well-ventilated area; keep vermiculite damp while using it; avoid bringing dust from vermiculite use into the home on clothing; and use premixed potting soil, which is less likely to generate dust.
The regulations described above and other actions, coupled with widespread public concern about the health hazards of asbestos, have resulted in a significant annual decline in U.S. use of asbestos. Domestic consumption of asbestos amounted to about 803,000 metric tons in 1973, but it had dropped to about 2,400 metric tons by 2005 (3, 5).
Source: http://www.cancer.gov/cancertopics/factsheet/Risk/asbestos
No comments:
Post a Comment