Asbestos Exposure and Building Materials

Asbestos Exposure and Building Materials Asbestos is a group of minerals that occur naturally as bundles of fibers that can be separated into threads. In the 1800s, asbestos became very desirable as an ingredient in construction materials. It is very strong, lightweight, resistant to chemical destruction, does not conduct heat or electricity, and it is fireproof. The fibers can even be woven into textiles.

There are two subgroups of asbestos based on fiber shape. Chrysotile asbestos has long curly fibers, and amphibole asbestos has straight, needle-like fibers. The amphiboles include actinolite, tremolite, anthophyllite, crocidolite, and amosite asbestos. Chrysotile is the form that has been used the most in industrial applications. It is the only type currently mined on a large scale and is found in most of the asbestos-containing building materials currently being produced.

Asbestos has been mined and used in the US since the late 1800s. The building and construction industries use it primarily for insulation, roofing, fireproofing and soundproofing. Shipbuilding has historically used it for insulation around pipes and boilers.

Unfortunately, the characteristics of asbestos that make it so valuable for construction materials make it very dangerous to the human body. When asbestos fibers are inhaled, they may stay in the lungs for a very long time, causing inflammation and eventually some very serious diseases (1).

The medical community began to note the connection between asbestos in the workplace and serious disease during the late1800s. In 1906, a British doctor reported to a Parliamentary committee on a patient who had died at the age of 33. He concluded that the death was due to lung damage caused by asbestos dust. The patient had worked in the carding room of an asbestos textile plant. This is generally regarded as the first proven case of pulmonary disease from asbestos exposure. By 1930 there had been reports in British and US medical journals about asbestosis. Recommendations made in these reports included limiting dust exposure and providing medical examinations (2). In 1938 the United States Public Health Service issued guidelines on asbestos exposure.

These recommendations were ignored during World War II and even afterwards. During the war, the US government needed several hundred tons of asbestos every day, primarily for shipbuilding. There was even a moratorium placed on civilian uses for fear of running out of the valuable commodity. The construction boom after the war made heavy use of asbestos building materials (3). From 1940 through 1970, an estimated 27.5 million individuals were exposed to asbestos at work, in a very wide range of job sites and trades.

Since the 1970s, the U.S. Environmental Protection Agency (EPA) has stepped in with bans of certain asbestos-containing materials and regulation of others. Many of the asbestos-containing construction materials used through 1980 remain in older buildings as an enduring health hazard.  It is now estimated that 1.3 million workers in construction and general industry have significant exposure to asbestos on the job. The heaviest exposure occurs in construction, and especially during removal of asbestos during renovation or demolition.

It is a common misconception that all asbestos-containing building materials were banned by the EPA in 1989. In fact, the EPA banned many asbestos products in 1989 under the Toxic Substance Control Act, but most of the ban was overturned on appeal by the Fifth Circuit court in 1991.  The materials that remain banned are asbestos-containing corrugated paper, rollboard, commercial paper, specialty paper, flooring felt, and new uses of asbestos.  Asbestos is still allowed for use in other construction materials, though many corporations have made voluntary substitutions in their products out of concern for public health and consumer demand. An extensive list of asbestos-containing building materials published by the EPA can be found at http://www.epa.gov/Region06/6pd/asbestos/asbmatl.htm .

The EPA regulates asbestos-containing building materials according to their friability. A friable asbestos-containing material (ACM) contains more than 1% asbestos and can be crumbled, pulverized or reduced to powder by hand pressure when it is dry. A nonfriable ACM is one containing more than 1% asbestos that is not easily crumbled or pulverized under hand pressure. The EPA futher divides nonfriable ACMs into two categories, depending upon how likely they are to become friable when damaged. According to the EPA, a regulated asbestos-containing material (RACM) is any friable ACM and any nonfriable ACM likely to become friable through damage or destruction. The EPA regulates the handling of any RACM during renovation, removal, burning, demolition, transport and disposal. These rules may vary on a state and local level (4).

While the EPA regulates the disposition of asbestos materials, the U.S. Department of Labor regulates the treatment of employees working with asbestos. The Occupational Safety and Health Adminstration (OSHA) has three published standards mandating worker protection: 29 CRF 1926.1101 covers construction work, 29 CFR 1915.1001 covers exposure during work in shipyards, and 29 CFR 1910.1001 applies to general industry, such as custodian work, manufacture of asbestos textiles, and brake and clutch repair.

These standards classify the degree of potential hazard of asbestos work activities, with Class I work being the most hazardous, and Class IV being the least (5). 

OSHA sets a maximum exposure limit for construction workers and others working with asbestos. Workplace exposure must be limited to 0.1 fiber per cubic centimeter of air averaged over an 8-hour work shift. For short-term exposure, the limit is 1 fiber per cubic centimeter of air averaged over a 30-minute timespan.  Employers are required to monitor for the presence of asbestos, provide protective gear including respirators, properly label and warn of asbestos-containing materials and contaminated areas, provide clean rooms and filtered air where necessary, keep adequate records and provide medical exams (6).

'Asbestos Exposure and Building Materials' Resources:
  1. National Cancer Institute. Asbestos Exposure: Questions and Answers. National Cancer Institute FactSheet. 2007 February.
    Accessed: 20 August 2007.
  2. Baron and Budd, P.C. Occupational and Environmental Exposure to Asbestos in the U.S. Asbestos Awareness. 2006.
    Accessed: 20 August 2007.
  3. Scheberle, D. Indecent Exposure. Forum for Applied Research and Public Policy. 1998 Summer. Vol. 13 (2), pp. 110-114.
  4. U.S. Environmental Protection Agency. “Demolition Practices Under the Asbestos NESHAP.” Region 4, Asbestos (2007).
    Accessed: 14 July 2007.
  5. US Department of Labor. Occupational Safety and Health Administration. What is Asbestos? OSHA Fact Sheet.2002.
    Accessed: 20 August 2007.
  6. US. Department of Labor. Better Protection Against Asbestos in the Workplace. Fact Sheet No. OSHA 92-06.
    Accessed: 20 August 2007.