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Chapter 2: What is Asbestos?

Asbestos is a naturally occurring, heat-resistant mineral that has been used for thousands of years. Archaeologists have found evidence that humans in what is now Finland used asbestos minerals to strengthen cooking pots and utensils 4,500 years ago; the Roman emperor Charlemagne was reputed to have a tablecloth made of asbestos during his reign from 800 to 814; and Marco Polo wrote of being offered clothing that couldn’t burn during his travels in Siberia.

Some archaeologists believe that ancient societies made asbestos shrouds for their rulers to prevent their ashes from being mixed with materials from the funeral pyre, and others have found evidence indicating asbestos was used to make “perpetual” wicks for lamps – a practice that continued for centuries. Indeed, the very word asbestos comes from the ancient Greek word for “unquenchable.”

In this chapter, learn what asbestos is, how it has been and continues to be used, and how its health hazards were discovered and documented.

Types of Asbestos and Their Uses

Asbestos actually is a set of six minerals. All six asbestos minerals – actinolite, amosite, anthophyllite, chrysotile, crocidolite and tremolite – are resistant to heat, fire and damage from chemicals or electricity. Asbestos also absorbs sound, making it useful for such applications as ceiling tile.

Asbestos minerals are composed of very thin, fibrous crystals. Of the six types of asbestos minerals, five are amphibole, or needle-like crystals. Only chrysotile, or white asbestos, crystals are curly (or serpentine). Because of its unique structure, white asbestos is more flexible than its needle-like counterparts and can be woven into fabric.

Although humans have used asbestos sporadically for thousands of years, the mineral came into widespread industrial use in the mid-1800s. In the United States, the first asbestos mine was developed on Staten Island in the late 1850s, and by 1866, asbestos was in common use as insulation in the U.S. and Canada. Less than 100 years later, asbestos was common in concrete, bricks, fireplace mortar, pipes, and fire-retardant coatings.

About 95 percent of all asbestos-containing materials in U.S. buildings are made with white asbestos, which has been used in the following ways:

 

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Amosite, also known as brown asbestos, is the second most common type of asbestos found in U.S. buildings. Although most developed countries banned all forms of amphibole, or needle-like, asbestos by the mid-1990s, products containing these kinds of asbestos still can be found in many structures. Such products include:

  • Low-density insulating board and ceiling tiles
  • Asbestos-reinforced cement sheets and pipes used in construction and casings for water, electrical and telecommunications systems
  • Thermal and chemical insulation

Over the years, asbestos found its way into far more than just building supplies and car parts. At one point, artificial Christmas snow, or flocking, was made with asbestos. Kent brand cigarettes used asbestos in its filters in the 1950s. And before the 1960s, gas mask filters contained asbestos. Other filters, including those used to remove particulates from chemical compounds and even wine, also were made with asbestos. It was even used in lawn furniture and some art supplies.

Asbestos also can contaminate other minerals. For example, the mineral vermiculite, which has been used as an asbestos substitute, sometimes contains small amounts of asbestos. One vermiculite mine in Libby, Montana, was contaminated and the Environmental Protection Agency has designated it a Superfund clean-up area.

In 2000, lab tests showed asbestos contamination in major brands of crayons, including Crayola. The asbestos was believed to have contaminated the industrial-grade talc the manufacturers used to make their crayons, and, as a result of the tests, all U.S. crayon manufacturers removed talc from their formulations.

Discovery of the Health Hazards of Asbestos

The nature of asbestos makes it especially easy to inhale. Asbestos fibers are extremely fragile and can break into tiny particles that are invisible to the naked eye, and activities like mixing, cutting, scraping, and even sweeping can make the particles airborne.

Although different types of asbestos have different chemical properties, all types are now known to be harmful to human health. Since at least the early 1900s, when researchers noticed a large number of lung problems and early deaths in asbestos mining towns, physicians and public health officials have investigated the impacts of asbestos. Many companies failed to do any research to determine whether asbestos was harmful. Other companies knew of its dangers but hid that knowledge from workers and their families.

The following timeline highlights some of the more important discoveries and documentation regarding the toxicity of asbestos.

Asbestos-Related Dangers Timeline
Year Event
1898 Annual report of Britain’s Chief Inspector of Factories notes that asbestos has “easily demonstrated” health risks.
1906 First documented asbestos-related death.
1918 A U.S. study notes that “in the practice of American and Canadian life insurance companies, asbestos workers are generally declined on account of the assumed health-injurious conditions of the industry.”
1924 First diagnosis of asbestosis (see Chapter 3).
1927 First known U.S worker’s compensation claim for asbestos-related disease.
Late 1920s A large public health study, generally known as the Merewether Report (named after one of its authors), found that about 25 percent of examined British asbestos-textile workers suffered from lung disease, leading to stronger regulation of asbestos-related manufacturing.
1931 The term mesothelioma makes its first appearance in the medical literature.
1932 In a letter to an asbestos manufacturer, the U.S. Bureau of Mines notes that “asbestos dust is one of the most dangerous dusts to which man is exposed.”
1934 Officials of two major asbestos companies edit an article about diseases in asbestos workers to minimize the reported dangers of asbestos dust.
1936 A group of asbestos companies sponsored research on the health effects of asbestos dust, but refused to allow the research findings to be published without their approval.
1944 A report by Metropolitan Life Insurance Company finds that more than 20 percent of a group of 195 asbestos miners suffer from asbestosis
(see Chapter 3).
1951 Asbestos companies deleted all references to cancer in research they had sponsored before agreeing to publication of the research findings.
1953 Officials at National Gypsum prevent delivery of a letter the company’s safety director had written to the Indiana Division of Industrial Hygiene. The safety director had recommended that workers mixing acoustic plaster wear respirators because of the product’s asbestos content.
1953 Mesothelioma is reported in an asbestos insulator.
1955 A major epidemiological study demonstrates that asbestos workers have a tenfold risk above the general population of contracting lung cancer.
1960 Another epidemiological study confirms reports that exposure to asbestos causes mesothelioma. This study also included the children and wives of asbestos workers who contracted mesothelioma.
1964 Dr. Irving Selikoff, a major researcher at Mt. Sinai Hospital in New York, confirms widespread disease among asbestos workers and from family members living with asbestos workers. A large number of job titles were implicated in the report, including construction workers, electricians, plumbers, and carpenters. Selikoff pointed out that asbestos did not “respect” job titles and could harm any person who breathed in asbestos.
Late 1960s After 1964, the medical literature continued to identify asbestos as a major carcinogen and environmental hazard. Over 200 publications described the hazards of asbestos by the end of the 1960’s.
Late 1970s The U.S. Consumer Product Safety Commission bans the use of asbestos in gas fireplaces and wallboard patching materials because using them can release asbestos into the air.
1979 Electric hairdryer manufacturers voluntarily stop using asbestos in their products.
1980s The Health Effects Institute in Cambridge, Massachusetts begins evaluating the lifetime cancer risks of people who work and live in buildings with asbestos products, as well as the risk of service workers in such buildings.
1989 The Environmental Protection Agency issues the Asbestos Ban and Phase Out Rule. The rule is subsequently thrown out by a federal appeals court, so uses developed before 1989 are still legal in the U.S.

Asbestos is still not banned in the U.S.
2000 Although the Consumer Product Safety Commission concludes that the risk posed by asbestos fibers in crayons is low, U.S. crayon manufactures agree to stop using talc in their products.
2000 The Environmental Protection Agency determines that asbestos-contaminated vermiculite poses a risk and recommends that consumers take measures to reduce dust generation when working with vermiculite, such as making it damp, using it in well-ventilated areas, and using premixed potting soil.
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