Until recently the use of asbestos as an insulating compound was widespread, as the substance is inexpensive to mine and process. Asbestos fibers are heat resistant and do not conduct electricity which made the mineral ideal for use in plaster and wallboards. Structures that housed industries such as metalworking, power production and smelting often used asbestos as part of the fireproofing plan, but exposure to this silicate mineral can lead to serious health problems including mesothelioma.
Once mined, asbestos can be separated from ore and shipped to processing plants where it is packaged for delivery to companies that use it as an insulating material. This practice was rampant throughout most of the 20th century until health warnings about the dangers of asbestos reached the public’s ears. A number of companies manufactured sheetrock and drywall products that contained asbestos fibers, or made paints and other chemicals that could be applied directly to wall panels and make them much more fire resistant.
Wallboards made with asbestos were usually placed in areas where heat was produced or there was danger of fire. Boiler rooms were very often shielded by using asbestos-laden wall panels and ceiling tiles, and steam pipes were wrapped with a paste made of asbestos and drywall mud. Plaster was mixed with asbestos and applied to the surface of sheetrock, making the wall nearly fireproof. As these buildings aged the microscopic asbestos fibers often became loosened, and when workers made remodeling changes to structures the act of sawing, drilling or tearing down these walls resulted in the freeing of countless asbestos fibers.
OSHA has put together a list of materials that likely contain asbestos, although a visual inspection cannot determine the existence of these fibers. Thermal system insulation, sprayed-on fire retardant chemicals, resilient flooring and troweled-on cement floors or other surface protection that was part of the construction industry prior to the 1980s are only a few of the “watch list” items that may contain asbestos.
Long-term exposure to asbestos can result in the inhalation of airborne fibers, which settle in the lungs and become trapped. After years or even decades these fibers can affect the surrounding tissue and affect the DNA of dividing cells much like any cancerous agent. Mesothelioma is the most deadly of these diseases, and can show symptoms as many as years after initial exposure. By the time a mesothelioma diagnosis has been made the cancer has usually spread too far to be stopped. Other lung cancers, asbestosis and certain benign growths in the stomach or intestine have been blamed on past exposure to asbestos in wallboards or ceiling tiles.