Asbestos is the name given to a number of naturally occurring, fibrous silicate minerals mined for their useful properties such as thermal insulation, chemical and thermal stability, and high tensile strength. Asbestos is commonly used as an acoustic insulator, and in thermal insulation, fire proofing and other building materials. Many products in use today still contain asbestos.

Asbestos is made up of microscopic bundles of fibers that may become airborne when asbestos-containing materials are damaged or disturbed. When these fibers get into the air they may be inhaled into the lungs, where they can cause significant health problems.

Information about the health hazards of asbestos came to light over a century ago. In 1898, British factory inspectors recognized the asbestos exposure was a health risk for workers. More than 100 years ago, in 1906, a London physician found asbestos fibers in the lungs of a worker who died from pulmonary fibrosis—scarring in his lungs. And in 1912, scientists used animal studies to show that asbestos inhalation causes pulmonary fibrosis. The U.S. Bureau of Labor Statistics reported in 1918 the “unusually high death rate” among asbestos workers.
By the 1920s, asbestosis was receiving increased attention from scientists. A series of papers appeared in British Medical Journal in 1924 on asbestosis—the disease named for the mineral that causes it. In 1930, two scientists, Drs. Merewether and Price, published a historic report on the asbestos textile industry and found a “definite occupational risk among asbestos workers as a class.” Highlights from the Merewether and Lewis report were republished in two prominent medical journals, the Journal of the American Medical Association (JAMA) and Lancet, including the astounding finding that “80% of asbestos workers employed for 20 years or more develop asbestosis.”

In the 1930s, scientists began to connect asbestos and cancer. Numerous well-known medical journals published scientific studies that linked asbestos exposure to cancer. German physicians identified lung cancer as an occupational disease of asbestos workers in 1938. And by 1945 it was accepted by the medical and scientific communities “in all countries” that asbestos is a carcinogen (cancer causing). In 1955, scientists confirmed that there was a definite connection between asbestos exposure and the development of a form of lung cancer that later came to be known as mesothelioma.

Despite the growing evidence of health risks of asbestos exposure, manufacturers and companies continued its use in many of their projects. In many cases, these manufacturers were aware of the potential health risks of asbestos exposure but chose to ignore them. These same companies also ignored the availability of safer alternative materials like fiberglass that were being developed at the time Unfortunately, the victims were, for the most part, men of working families who had no knowledge of the potential health risks of asbestos exposure.

Asbestos-containing products are used for thermal insulation. Most insulation materials before the mid-1970s did contain some degree of asbestos. Countless products have, at one time or another, contained asbestos, including (but not limited to): thermal seals, insulating cement, asbestos cloth, asbestos cement pipe, pipe-covering, refractory and boiler insulation materials, packing materials, fireproofing spray, transite board, gaskets, insulating block, joint compound, duct insulation for heating, vinyl floor tile, ceiling tile, adhesives, mastics, coatings, roofing products, acoustical textures, insulated electrical wire and panels, ventilation and air conditioning (HVAC) systems, and brake and clutch assemblies.

 The United States Occupational Safety and Health Administration (OSHA) has stated that no other toxic substance has more clearly demonstrated lethal health effects on humans than asbestos has. From the years 1940 to 1970, approximately 27.5 million individuals had potential work-related asbestos exposure. It has been estimated that only the number of workers exposed as a consequence of asbestos brake and clutch work is approximately 900,000. In 1989, EPA issued a rule banning most asbestos-containing products.  In 1991, however, this regulation was overturned by the Fifth Circuit Court of Appeals. EPA was unable to persuade the Justice Department to appeal the ruling. Asbestos products continue to be manufactured and imported for use here.

While more than 30 countries have banned the use of asbestos, the U.S. government has not.  However, four years after the introduction of the original bill, the U.S. Senate finally and unanimously passed a bill to ban asbestos, in 2007. The bill had faced opposition from the stone and mineral industries which had concerns about low levels (under 1%) of asbestos contamination of some of their materials. In order to overcome their opposition, compromises were made and the revised U.S. bill restricted the national prohibitions to materials with more than 1% asbestos. It is noteworthy that the figure of 1% has no health basis. Materials with well under 1% of asbestos can release high levels of airborne asbestos when used or disturbed.

Although manufacturers have removed the asbestos from many new products, asbestos may still be found at mines. Moreover, asbestos-containing building materials such as reinforced cements, could present a hazard during maintenance, construction, remodeling, rehabilitation, or demolition projects. Asbestos in manufactured products, such as electrical insulation, joint and packing compounds, automotive clutch and brake linings, and fireproof protective clothing and welding blankets, could present a hazard during activities that may cause a release of fibers.