Asbestos is a group of silicate minerals known to cause a rare form of cancer called mesothelioma.
Key Points about Asbestos
- Asbestos is the only scientifically proven cause of mesothelioma cancer.
- Asbestos is a general term that refers to six specific fibrous minerals.
- All types of asbestos share common properties, including a fibrous texture and resistance to fire, heat, and electricity.
- Since the late 19th century, asbestos has been used in an abundance of construction materials and household products.
- Although it is a known carcinogen, asbestos has yet to be banned in the United States.
What Is Asbestos?
Asbestos refers to a number of unique substances that are members of the serpentine and amphibole mineral groups. Asbestos is very resistant to chemicals, electricity, and water, making it a good insulator for a number of Industrial Age products such as steam engines, ovens, electrical generators, turbines, and boilers. Because it is malleable, it is useful for building materials (roofs, tiles, wall board, etc.) as well as binding and strengthening other products.
The Six Types of Asbestos
|Chrysotile (White) – The most common form of asbestos. Often found in homes, particularly in floors, walls, ceilings and roofs.||Tremolite (Many Colors) – Not mined commercially. Found as a contaminant in talc powders, vermiculite, and chrysotile.|
|Amosite (Brown) – Found in Africa. Often used in pipe insulation, cement sheets, and ceiling tiles.||Anthophyllite (Gray-Brown) – Not mined commercially. Found as a contaminant in flooring products.|
|Crocidolite (Blue) – Mined in Australia, South Africa, and Bolivia. Found in cement materials, spray-on coatings, pipe insulation, and steam engines.||Actinolite (Green or Colorless) – Not mined commercially. Found as a contaminant in various products.|
Other silicate minerals can share some asbestos properties, or may be found naturally in the same location as asbestos, leading to cross contamination. Such minerals include erionite, vermiculite, taconite, and talc.
Asbestos and Mesothelioma
In the 1960s, asbestos was shown by researchers to cause a rare form of cancer known as mesothelioma that forms in the linings of the lungs, abdomen, heart, or testes. Although some forms of asbestos may be more harmful than others, all types of asbestos can lead to cancer or other diseases or conditions. It typically takes decades after exposure to asbestos for mesothelioma to form.
Other Asbestos-Related Diseases and Conditions
|Asbestosis – A severe form of fibrosis, in which fibrous connective tissue develops around the lung cavity. Symptoms include shortness of breath and irreversible lung scarring. This is an industrial disease from exposure to high levels of any type of asbestos.||Pleural Effusion – Unnatural increase in fluid around the lung cavity. Pleural effusions can be an early manifestation of asbestos-related diseases and can appear within 10 years of exposure. Some pleural effusion can be benign.||Asbestos Warts – Unlike other asbestos-related diseases, asbestos warts appear on the outside of the body rather than internally. They can occur on the surface of the skin where asbestos fibers have been embedded, forming calluses.|
|Lung Cancer – Abnormal growth of cells in the lungs. The most common cause of lung cancer is smoking tobacco products. However, the presence of asbestos can also be a factor in the development of lung cancer, especially in combination with tobacco smoking.||Pleural Plaque – Thickened areas that can be seen on the surface of the pleura. Pleural plaques don’t become cancerous or cause breathing problems; however, they can be a symptom of other conditions, such as mesothelioma. They often form 20 to 30 years after asbestos exposure.||Pneumothorax – Air accumulated in the thoracic (chest) cavity, which then causes the lung to collapse. This can occur spontaneously or as a result of injury or lung disease. Mesothelioma can sometimes be misdiagnosed as pneumothorax.|
Most Common Uses of Asbestos
Humans have used asbestos as far back as prehistoric times when it was used in funeral shrouds, candle wicks, and pottery. In modern times, asbestos used increased significantly during the growth of the automotive and construction industries.
Asbestos has been used in just about all public and commercial buildings since before the 1900s in the United States, primarily because of its effectiveness as a fireproofing material for steel beams and columns.
Due to the strength and malleability of asbestos, it is added to adhesives, concrete, roof shingles, asphalt, pipes, wall board, and floor tiles. Since it is heat resistant, it is good for thermal insulation.
In the early 1800s, crocidolite was found in Africa, and in the late 1800s chrysotile was found in Quebec. Canada established the first commercial asbestos mines, and by 1870, Scotland, Germany, and England joined them in the global asbestos industry. In the 1880s, Australia began mining asbestos, and in the 1890s Finland joined in.
In the 1800s, asbestos mining was not mechanized, which made it a slow, manual process. Once it was industrialized and manpower increased, production increased dramatically, allowing new applications to be developed.
The U.S. Navy specified the use of asbestos in submarines in 1922, using chrysotile for gaskets, insulation, packing, and tape. By 1939, the United States defined asbestos as a critical material and began stockpiling it.
During World II, the British Admiralty controlled most merchant shipbuilding, including the distribution of asbestos. Asbestos resists corrosion and high temperature making it very useful for shipbuilding. However, asbestos accumulation in the air, skin, and clothing makes naval shipyard workers the most frequently exposed to its harmful effects.
Asbestos is found in various parts of vehicles, including internal combustion parts, brake pads, gaskets, and other places where friction and high temperatures occur. Due to the ubiquity of the mineral in automobile parts, many workers in the automotive industry – including mechanics, technicians, and factory employees – are at risk of asbestos exposure.
Clothing and Textiles
Due to its fibrous nature, asbestos can be used to make protective clothing and textiles, such as jackets and fire blankets for firefighters or the overalls worn by racecar drivers. Workers in industries that use open flames and/or high heat also may wear specialized clothing made with asbestos, such as protective gloves (such as gauntlets or mitts) and aprons. This includes industries such as glass making, foundries, the steel industry, welding, or even cooking.
In addition to clothing and protective gear, asbestos has been used in other textile applications, including carpeting, drapes and curtains, upholstery, and ironing board covers.
There are a number of domestic items made with asbestos because of its durability and fire- and heat-resistant properties. These include toys, personal items, appliances, and home construction materials. Other items include fire starters, gaskets, toasters, hair dryers, ironing board covers, electric blankets, burner pads, portable heaters, dishwashers, and much more.
In the 1930s to 1950s, artificial snow made of asbestos was a big hit, having been marketed for use in homes across the country. It was also used in such movies as The Wizard of Oz. Recently, asbestos has been found in children’s toys and tools, such as crayons.
Alternatives to Asbestos
Since the hazards associated with asbestos are well understood, there are a number of alternative products currently available. Most of these alternatives are readily available at the store or through a contractor.
|Polyurethane Foam – A petroleum byproduct used in roofing and insulation. (Some environmentally friendly polyurethane foams are made from soy byproducts.)||Icynene Foam – Based on castor oil, icynene foam is used primarily as insulation in applications when some air or vapor needs to pass through the foam.||Flour Filler – Made of wheat, rice flour, or pecan shell flour, these fillers are used to fill in cracks and crevices and are environmentally friendly alternatives to asbestos fillers and similar products.|
|Cellulose Fiber – Made of shredded newspaper, this green alternative to asbestos has become very popular in recent years. It is chemically treated to reduce mold and improve fire resistance. Cellulose fiber is used in roofing materials, partitions, and cement mixtures.||Thermoset Plastic Flour – Made of plastic, thermoset plastic flour is used as a heat, cold, and sound insulator. It is often mixed with other fillers to lower the cost.||Amorphous Silica Fabrics – Fiberglass-based insulation and protection fabrics used in aerospace shipyards, molten metals, and electric power generation.|
When Was Asbestos Banned?
Currently, asbestos is not banned in the United States, even though more than 50 other countries have banned it. Despite the overwhelming medical and scientific evidence that asbestos is dangerous in any amount, there have been a number of significant hurdles to banning asbestos in the U.S.
The Toxic Substances Control Act (TSCA), originally passed in 1976, banned the manufacture, importation, processing and distribution of certain asbestos materials. In July 1989, the EPA issued a ruling banning most asbestos products; however, this ruling was overturned by the Fifth Circuit Court of Appeals, allowing manufacturers to continue making asbestos products with “established uses” prior to 1989.
Progress in Banning Asbestos
In May 2016, one of the biggest hurdles preventing a ban on asbestos was cleared when Congress passed the Frank R. Lautenberg Chemical Safety for the 21st Century Act. Although this bill does not ban asbestos outright, it empowers the EPA to review and ban substances that it deems to be toxic, and in December 2016, the EPA announced a plan to review whether asbestos should be banned.
While it may take several years for an asbestos ban to be put in place – and perhaps many more years after that to fight asbestos industry interests in the court system – the passage of this bill brings the U.S. one step closer to banning asbestos for good.