There are several minerals commonly known as asbestos. These minerals can be used to make products strong, long-lasting and fire-resistant. Before 1990, asbestos was mainly used for insulating buildings and homes against cold weather and noise. It was also used for fireproofing. Industry, construction and commercial sectors have used, and, in some cases, continue to use, asbestos in products like:
- cement and plaster
- industrial furnaces and heating systems
- building insulation
- floor and ceiling tiles
- house siding
- car and truck brake pads
- vehicle transmission components, such as clutches
Asbestos refers to six unique substances that belong to the serpentine and amphibole mineral families: chrysotile, amosite, crocidolite, tremolite, anthophyllite, and actinolite.
These terms do not refer to mineral descriptions but to a broad term that refers to unique fibers. According to the Toxic Substances Control Act (TSCA), the asbestiform varieties of the following minerals are classified as asbestos.
Chrysotile Asbestos: Many studies have proven that exposure to chrysotile asbestos, commonly referred to as white asbestos, can cause a number of serious health conditions. While most commercial uses of asbestos in Canada have been of the chrysotile type, the use of this toxic mineral has declined significantly during the last few decades. Naturally occurring deposits of chrysotile are often accompanied by trace amounts of tremolite (amphibole) asbestos, which is considered more toxic than chrysotile. However, several reports have indicated that exposure to solely chrysotile asbestos fibers can occur and such exposure can be equally hazardous as exposure to amphibole asbestos types.
Scientists from the National Institute for Occupational Safety and Health concluded that chrysotile asbestos should be treated with virtually the same level of concern as the amphibole forms of asbestos.
Uses of Chrysotile Asbestos – In comparison to amphiboles, chrysotile fibers are generally finer with high flexibility and good heat resistance. Known as the most common asbestos mineral, chrysotile accounts for about 90 to 95 percent of asbestos used in commercial applications in the United States. This toxic mineral has been utilized in a number of products, including:
- Brake pads
- Brake linings
- Joint compound
- Roofing materials
Tremolite Asbestos: Tremolite is an amphibole. Tremolite fibers have been useful for commercial products because they are strong, flexible, heat-resistant, and can be spun and woven into cloth.
- Roofing materials
- Plumbing materials
Tremolite contains calcium, magnesium, silicon, hydrogen and oxygen. The mineral can be brown, gray, white or green and may appear to be transparent.
Amosite Asbestos: According to the American Cancer Society, exposure to amosite asbestos creates a higher risk of cancer in comparison with other types of asbestos. Several asbestos studies suggest exposure to amosite can cause lung cancer, mesothelioma and asbestosis.
In its natural state, amosite is known as the mineral grunerite. Commercially, grunerite is referred to as amosite or brown asbestos. Approximately 80,000 tons of amosite were mined in the Transvaal province of South Africa by 1970.
Commercial products that have been manufactured with amosite include:
- Cement sheets
- Thermal insulation
- Plumbing insulation
- Insulation boards
- Chemical insulation
- Electrical insulation
- Roofing products
- Fire protection
- Gaskets, lagging
- Tiles, including those for ceilings, roofs and floors
The U.S. Environmental Protection Agency (EPA) has determined amosite to be the second most commonly used mineral type of asbestos in the United States.
Actinolite Asbestos: Actinolite is an amphibole that is generally dark in color. Actinolite can appear in multiple forms such as dense and compact or brittle and fibrous, along with different colors, including white, gray, brown or green. The mineral’s name stems from the Greek “aktinos,” meaning “ray” or “beam,” stemming from its radiating fibrous form.
Actinolite is made up of other minerals and substances such as:
- Uses of Actinolite Asbestos
Actinolite is typically used with the similar mineral vermiculite, which expands when heated. Vermiculite and actinolite make for an effective, light-weight insulation material.
Other common uses for actinolite and vermiculite include:
- Insulation material
- Concrete materials used in construction
- Structural fireproofing
- Actinolite may still be present in buildings, homes or other locations that were constructed before asbestos was known to be a hazardous material.
- Joint compounds
- Children’s toys
Crocidolite Asbestos: Multiple asbestos studies suggest crocidolite may be responsible for more deaths than any other type of asbestos because its fibers are so thin — about the diameter of a strand of hair. When airborne, these fibers can be inhaled easily and become lodged in the lining of the lungs, more so than other forms of asbestos forms. Once inside the body, the fibers do not break down easily. This can lead to potentially life-threatening lung and abdominal conditions, including lung cancer, mesothelioma and asbestosis.
These health risks are especially serious among crocidolite miners. An estimated 18 percent of crocidolite miners die from mesothelioma, research shows, and people living near crocidolite mines may also have increased risks for mesothelioma and other diseases.
The existence of crocidolite asbestos was first established in the early 1800s in South Africa. At the time, the mineral was known as “wooly stone,” but interest in the naturally occurring mineral didn’t take off until the 1880s, and large mining efforts of the material didn’t begin until the early 1900s. Crocidolite is also known as “blue” asbestos. This form can be translucent or nearly opaque (which means light can”t penetrate it). The most common mining sites for this type of asbestos were Bolivia, Australia and southern Africa.
Today, crocidolite mining has virtually ceased because of both physical limitations and serious health risks. Crocidolite-containing materials are also more brittle than other amphibole asbestos products, meaning they break down sooner and can more readily lead to asbestos exposure. Crocidolite is categorized as an amphibole, which is usually a needle-like mineral that forms in crystal groupings, either as fibers or columns. Typically, crocidolite fibers can be curved or straight. While brittle, the fibers are flexible enough to bend beyond 90 degrees before breaking.
Uses of Crocidolite Asbestos – Like other types of asbestos, crocidolite was used to make a number of commercial and industrial products. It did have a drawback that other asbestos types did not: It is less heat-resistant, making it less useful for industrial manufacturing.
- Ceiling tiles
- Fire protection
- Insulation boards
- Chemical insulation
- Spray-on insulation
- Acid storage battery casings
- Water encasement (enclosing)
- Cement sheets containing asbestos
- Electrical or telecommunication wires
- Thermal insulation (lagging and gaskets)
- Millboards (commercial ovens and steam pipes)
Anthophyllite asbestos is known to cause asbestos-related diseases, however, most studies indicate the risk of developing mesothelioma from anthophyllite exposure is much less than it is from exposure to other types of asbestos.
Although it took much longer for anthophyllite to be recognized as a mesothelioma risk than it did for amosite, chrysotile and crocidolite asbestos, there is a clear connection from exposure to it and to the development of mesothelioma.
Uses of Anthophyllite Asbestos – Anthophyllite is one of the rarest types of asbestos and does not have a long history of commercial use. The mining of this mineral began in Finland in 1890. Since then, smaller deposits were mined in North Carolina and Georgia.
While considered to be among the noncommercial types of asbestos, anthophyllite has been used in products containing minerals such as vermiculite and talc. Traces of anthophyllite may be present in talc and related products such as talcum powder.