Asbestos (Mineral)

Where Found

Asbestos-form minerals are common in metamorphic rocks all over the world, but the great majority of the world’s production has come from only two types of deposits. The most important of these, represented by major deposits in Canada and Russia, are produced by metamorphic alteration of alpine-type ultramafic rocks—dark-colored, high-density igneous rocks low in silica and high in iron and magnesium. The second major type of deposit, much less important than the first, is produced by the metamorphism of layered ultramafic intrusions. Important deposits of this type occur in Africa.

Primary Uses

The major use in the world market is in the manufacturing of asbestos-cement products. Other important uses are in friction products, such as clutch facings and brake linings, and in roofing products. Asbestos with particularly long fibers is spun into cloth and used to manufacture fire-resistant conveyor belts, safety clothing, and other types of fireproof textiles, such as curtains and blankets. Asbestos has also been used in the chlor-alkali industry to produce sodium hydroxide as well as chlorine for water treatment.

Technical Definition

There are six different minerals that have been produced as asbestos. By far the most important one, accounting for approximately 95 percent of the world production and consumption, is chrysotile, or “white asbestos,” a fibrous form of the serpentine group of minerals. The serpentines are hydrous magnesium silicates with a layered structure. Commercial deposits of chrysotile occur in ultramafic rocks, particularly peridotite, that have undergone metamorphism.

The five other forms of asbestos are members of the amphibole group of minerals. In order of importance, these are crocidolite (“blue asbestos”), amosite (“brown asbestos”), anthophyllite, tremolite, and actinolite. The amphiboles are silicates with a chainlike structure and an extremely variable composition.

Description, Distribution, and Forms

Asbestos is not a or a rock; rather, it is an industrial term used to refer to a few minerals that sometimes occur in a fibrous form. Asbestos refers to a few types of minerals that sometimes occur as long, slender fibers. It is this fibrous nature that accounts for both the usefulness and hazards of asbestos. Asbestos minerals differ from one another in many ways, but they share great resistance to heat, chemical attack, and friction. These properties make asbestos an important industrial commodity.

The major asbestos deposits of the world are located in Canada, China, Russia, Kazakhstan, and some African countries. By 2022 Russia was by far the biggest exporter of mineral asbestos, followed by Kazakhstan, China, and Brazil. The Thetford District in the eastern townships of Quebec, Canada, and the Bazhenov area in the Ural Mountains of south-central Russia and Kazakhstan were previously the most productive sites for asbestos. Thetford production was continuous from 1878 until the Jeffery open-pit asbestos mine closed in 2011. The of both of these districts is similar. Chrysotile occurs as veins and fissures in ultramafic rock that has undergone metamorphism during mountain-building events. The Ural deposits have the greater tonnage of production, but the Thetford deposits are of a higher grade and produced more long-fiber asbestos. African production includes both chrysotile and amphibole asbestos (amosite and crocidolite) and comes from Zimbabwe, South Africa, and Eswatini (formerly called Swaziland). Zimbabwean production is minor compared to those of Russia, China, and Kazakhstan, whose combined output accounted for most of the world’s total production in 2022.

Production began to decline in the late 1970s due to health hazards. The rate of decline has leveled off from the late 1980s but is projected to continue because of opposition to the use of asbestos in building and consumer products. Decline in production in the United States was sharper, falling by more than 90 percent from the early 1970s to the end of the 1990s. The United States ceased production of asbestos in 2002. Globally mine production dropped from 2 million metric tons in 2010 to 1.3 million in 2023.

History

Neolithic Scandinavians and ancient Romans were among the first to use asbestos. The former embedded asbestos within their pottery, while the latter wove it into cloth for cremations and for permanent lamp wicks. In medieval Europe, asbestos was employed as insulation in armor and to assist with trebuchet attacks. Later Europeans began using it for wall plaster. The development of asbestos as an important industrial mineral began with the opening of the world’s first great deposit in eastern Quebec, Canada, in 1878.

Obtaining Asbestos

Fibers with a length-to-width ratio greater than fifty to one command the highest price because they can be mixed with other fibers and spun or milled into cloth. The shorter, or “nonspinning,” fibers are generally made into compressed, molded, or cast products, such as asbestos pipe and sheet, in which the fibers are added to a binder such as portland cement or plastic. Such products account for most of the asbestos produced each year. Of the six different minerals that have been produced as asbestos, only crocidolite and amosite have been produced in important quantities. Production of anthophyllite, tremolite, and actinolite has been extremely limited and was nonexistent by the end of the twentieth century.

Uses of Asbestos

Although the individual properties of asbestos minerals differ from one another, they share to varying degrees several properties that make them useful and cost-effective. These include nonflammability, great resistance to heat and acid attack, high tensile strength and flexibility, low electrical conductivity, resistance to friction, and a fibrous habit.

Over a span of only a few years, the public’s view of asbestos changed dramatically: Once considered a useful commodity, asbestos became known as an extremely dangerous material. The change began with passage of the Clean Air Act (1972), which classified asbestos as a carcinogenic material because studies of workers exposed to high concentrations of asbestos dust for many years showed a high incidence of asbestosis, a lung disease that decreases the ability to breathe, and mesothelioma, a cancer of the lungs. Then, in 1973, a lawsuit against a number of asbestos manufacturers on behalf of an asbestos worker was decided against the companies. Litigation mounted, and, in 1982, manufacturer Johns-Manville filed for bankruptcy in the face of overwhelming litigation; eventually, as a compromise measure, the company established a $2.5 billion fund to pay future asbestos claims.

Widespread publicity concerning asbestos hazards led to a near hysteria among the general public; many people were afraid to send their children to a school unless asbestos insulation had been removed. People brought lawsuits demanding that asbestos be removed from public buildings. The courts awarded large damage rewards based on the argument that low-level exposure to asbestos should be considered dangerous because a safe level of exposure had not been scientifically established. This led to the “single fiber” concept—that exposure to only one fiber of asbestos may be deadly—in keeping with a widely held public perception that there should be no exposure to carcinogenic materials in the environment. The “asbestos scare” was largely the result of mass media sensationalism and resultant political and legal pressure rather than the result of scientific investigation. For example, very few people realized that, according to scientific estimates, a person breathing normal outdoor air inhales nearly 4,000 asbestos fibers per day, or more than 100 million over a lifetime.

Most common uses of asbestos—applications such as pipeline insulation, clothing, and roofing felt—were banned in the United States in 1989 by the Environmental Protection Agency (EPA) as part of the agency's final rule under Section 6 of the Toxic Substances Control Act (TSCA). The ban for most of the products under this final rule was overturned in 1991 by the Fifth Circuit Court of Appeals. According to the EPA, the TSCA ban remained in effect for commercial paper, corrugated paper, specialty paper, flooring felt, and rollboard, as well as so-called new uses of asbestos in products that had not historically contained it. The EPA also banned sprays containing more than 1 percent asbestos from being used on buildings, structures, pipes, and conduits unless the sprays meet certain specifications. In 2024, the EPA banned the import and use of chrysolite as well.

Asbestos can be a health hazard, but the seriousness depends on the length of exposure, the amount of asbestos in the air, and the type of asbestos involved. The danger to miners and others working with asbestos in unprotected conditions is demonstrable, but the danger to the general public from minimal exposure has been greatly exaggerated. Some researchers believe that the danger is so small as to be virtually nonexistent. Melvin Benarde in Asbestos: The Hazardous Fiber (1990) outlined the statistical risks (the number of deaths expected per 100,000 people) for a number of potential hazards. The risk of dying from nonoccupational asbestos exposure is one-third the risk of being killed by lightning and nearly five thousand times less than the chance of dying in a car accident. Nevertheless, by the mid-1990s more than $35 billion had been spent on asbestos abatement in rental, commercial, and public buildings.

Some experts estimated that in the years from 1965 to 2029 the United States would see 432,465 asbestos-related cancers. Although this figure has been disputed by some epidemiologists and other experts, it is enough to indicate the misery that many will suffer because of their exposure to asbestos. Nevertheless, the litigation-centered approach to asbestos issues in the United States has been criticized. In a 2008 report, the Manhattan Institute’s Center for Legal Policy, a conservative think tank, described asbestos litigation as the longest-running mass tort in the history of the nation and arguably the most unjust. Some critics have claimed that the massive asbestos tort litigation is more likely to enrich lawyers than relieve victims. The Manhattan Institute estimated that of the $70 billion paid out by companies for asbestos claims by 2007, $40 billion had gone to plaintiffs and defense lawyers. Numerous companies were driven into bankruptcy by asbestos lawsuits, some of which had only a tangential connection to the original asbestos exposure. Of the twenty-nine companies that filed for bankruptcy in the years from 2000 to 2002 because of asbestos litigation, six were valued at more than $1 billion. These included such industrial giants as Owens Corning, W. R. Grace, and U.S. Gypsum. As the companies that directly produced asbestos went gone under, plaintiffs’ lawyers increasingly sued companies outside the asbestos and building products industry. Companies in more than one-half of all industries in the United States had been sued over asbestos. With the total eventual cost of asbestos litigation estimated at $200 billion, Congress considered several proposals to establish a compensation fund in place of litigation. In 2004, industrial states such as Michigan and Ohio enacted measures to implement some form of asbestos tort reform.

In the late 2010s and early 2020s, several major corporations facing asbestos lawsuits, including Johnson & Johnson, Saint-Gobain, Trane Technologies, and Georgia Pacific, employed the controversial “Texas two-step” business maneuver. In the Texas two-step, a company divides into two entities—one with all the liabilities of the original business, and the other, all the assets—and then the new company holding liabilities files for bankruptcy. Critics such as asbestos plaintiffs claim this is an abuse of the bankruptcy system designed to avoid payment to victims, while the corporations involved and their attorneys assert it is the best method for remuneration in such cases.

Although asbestos use has become rare in developed countries, the same cannot be said of developing economies. In over fifty countries, including most of Europe and North America, use of asbestos is strictly limited or banned by law. However, emerging nations have continued and even increased the use of asbestos in manufacturing and building. Countries such as China, India, and Indonesia were major consumers of asbestos in 2022. Asbestos mining is widespread in Africa. Many developing nations consider the low cost and the effectiveness of asbestos as an industrial material to outweigh the health risks. The adverse effects of asbestos as an industrial pollutant are below the surface and long-term. Many of these nations face a more obvious health risk from such epidemics as HIV/AIDS, cholera, tuberculosis, and malaria, which have been linked to poverty or inadequate infrastructure. Likewise, many developing nations have accepted a great deal of air, water, and ground pollution as the price of accelerating the growth of fragile economies. Asbestos has apparently been accepted as another pollutant. Certainly these countries lack the extensive and ubiquitous legal and regulatory system of the United States that has focused attention on asbestos. However, in some African nations, such as South Africa and Eswatini, compensation for workers suffering the effects of asbestos has been provided.

China is perhaps the most dynamic and fastest-growing of all emerging markets. Many have called China the most important economy of the twenty-first century. It is worth noting, therefore, some facts about asbestos consumption in China. China continues to make extensive use of asbestos. Production in China has remained steady. China was one of the five leading producers of asbestos and its leading consumer in 2023. Estimates indicated that more than 100,000 workers in China were exposed to asbestos. Although the Chinese government has official policies against pollutants, they are often not enforced.

With the United States and China taking such different approaches to the use of asbestos, it is not yet possible to speak of a unified world approach to this industrial product. Certainly its use, associated health risks, and remediation represent one of the most important confluences of industry, medical concerns, and law in the world economy.

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