Types of Asbestos
Asbestos Types by AHERA Classification
Technically speaking, “asbestos” is a commercial and legal term encompassing multiple types of minerals. The Asbestos Hazard Emergency Response Act (AHERA) classifies the asbestiform varieties of the following minerals as asbestos.
Chrysotile
Chrysotile (white asbestos) is the most commonly used form of asbestos. It can be found today in the roofs, ceilings, walls, and floors of homes and businesses. Manufacturers also used chrysotile asbestos in automobile brake linings, gaskets and boiler seals, and insulation for pipes, ducts, and appliances.
Amosite
Amosite (brown asbestos) was used most frequently in cement sheets and pipe insulation. It can also be found in insulating board, ceiling tiles, and thermal insulation products. Raw amosite asbestos is a type of asbestos used for commercial purposes.
Crocidolite
Crocidolite (blue asbestos) was commonly used to insulate steam engines. It was also used in some spray-on coatings, pipe insulation, plastics, and cement products. Raw crocidolite asbestos is a type of asbestos used for commercial purposes.
Anthophyllite
Anthophyllite was used in limited quantities for insulation products and construction materials. It also occurs as a contaminant in chrysotile asbestos, vermiculite, and talc. It may have a grey, dull green or white color. Raw anthophyllite asbestos is a type of asbestos used for commercial purposes.
Tremolite
Tremolite and actinolite are not used commercially, but they can be found as contaminants in chrysotile asbestos, vermiculite, and talc. These two chemically similar minerals can be brown, white, green, gray, or transparent. Raw tremolite asbestos is a type of asbestos used for commercial purposes.
Regulations and Research
The AHERA granted the U.S. Environmental Protection Agency (EPA) permission to regulate these six types of asbestos in 1986, and more than 50 countries have banned them completely.
In July 2020, a U.K. study successfully identified different types of asbestos in mesothelioma samples using a type of mass spectrometry, which identifies compounds by measuring their molecular weight. Researchers said the discovery can be used to help diagnose mesothelioma and prove the cancer was caused by asbestos exposure.
Is Asbestos Dangerous?
All types of asbestos are considered dangerous by leading health agencies, including the U.S. Department of Health and Human Services, the EPA, and the International Agency for Research on Cancer. Although some types of asbestos may be more hazardous than others, they all have the potential to cause serious diseases, including asbestosis, malignant mesothelioma, lung cancer, ovarian cancer, and laryngeal cancer.
The Two Mineral Families of Asbestos
Asbestos can be classified into two mineral families: serpentine and amphibole. Serpentine asbestos has curly fibers made up of sheets of crystals, and historically, the single type of asbestos from the serpentine family, chrysotile, has accounted for over 95% of all asbestos used worldwide. Amphibole asbestos, on the other hand, has needle-shaped fibers, and studies suggest that it takes much less exposure to amphibole asbestos to cause cancer compared to serpentine asbestos. The most commercially valuable types of amphibole asbestos are amosite and crocidolite, while anthophyllite, tremolite, and actinolite are considered non-commercial forms.
Opinions on the Most Dangerous Forms of Asbestos
Some agencies, such as the Health Protection Agency in the U.K., claim that amphibole varieties of asbestos are the most dangerous forms. However, the EPA has abandoned projects aimed at identifying which asbestos fiber types are the most toxic, as the overall regulation of asbestos and asbestiform minerals is a more pressing priority.
Chrysotile Asbestos: Overview and Uses
Chrysotile, also known as “white asbestos,” was widely used in various asbestos-containing products throughout the 20th century in the United States and Canada. Even though naturally occurring deposits of chrysotile may contain small amounts of amphibole asbestos, which increase its toxicity, exposure to chrysotile asbestos fibers alone is still hazardous and can cause serious health problems. The National Institute for Occupational Safety and Health (NIOSH) recommends treating chrysotile asbestos with the same level of concern as other forms of asbestos.
Some common products that may contain chrysotile asbestos include adhesives, brake pads, cement, drywall, fireproofing, gaskets, insulation, roofing, and vinyl tiles.
Amosite Asbestos: Overview and Uses
Amosite, also known as “brown asbestos,” was the second most commonly used type of asbestos in the United States, as determined by the U.S. Environmental Protection Agency. The mineral is naturally found as grunerite and was primarily mined in South Africa. According to the American Cancer Society, exposure to amosite asbestos poses a greater risk of cancer compared to the more commonly used chrysotile asbestos.
Products that may contain amosite asbestos include:
Cement sheets
Fire protection materials
Gaskets
Insulation
Roofing products
Vinyl tiles
Crocidolite Asbestos and its Health Risks
Crocidolite, also known as “blue asbestos,” is a highly toxic form of asbestos that has been linked to numerous serious illnesses. Its thin, needle-like fibers make it particularly dangerous, as they can easily penetrate deep into lung tissue and cause significant damage.
The primary mining sites for crocidolite asbestos were located in Bolivia, Australia, and South Africa, and it was commonly used in various industries throughout the 20th century.
Exposure to crocidolite asbestos has been linked to several serious health conditions, including lung cancer, mesothelioma, and asbestosis.
Crocidolite asbestos-containing products include:
Acid storage battery casings
Ceiling tiles
Cement sheets
Fireproofing
Insulation
Kent Micronite cigarette filters
Overview of Anthophyllite Asbestos
Anthophyllite is a less common form of asbestos that has not been widely used commercially. It was first mined in Finland, with smaller deposits found in other countries.
Products Containing Anthophyllite Asbestos:
Cement
Insulation
Roofing
Rubber
Tremolite and actinolite
Tremolite and actinolite asbestos were not typically used intentionally in commercial products, unlike other forms of asbestos. Instead, they were often extracted incidentally during the mining of other minerals. However, even small traces of these types of asbestos can be hazardous and may lead to the development of asbestos-related illnesses.