Asbestos is a naturally occurring stone-based collection of materials that was widely used in roofing and in other exterior and interior building materials. Once touted as a miraculous solution to assorted construction drawbacks and difficulties, asbestos has proven to be a dangerous component of construction materials. Yet, due to its many virtues, for many years it was added to an assortment of common products, from exterior siding to the tiles in your basement.
The use of asbestos fibers is not new: They have been known for at least 2000 years. Beginning in the late 1800s, asbestos was added to cement and asphalt, and by 1907 it had become a leading additive in asbestos-asphalt shingles in the United States and was also used in cement-asphalt shingles. Eventually, almost all petroleum-based roofing components once included asbestos fibers.Unlike other roofing products such as asphalt shingles and wood shakes, asbestos is not flammable; it is resistant to insect damage; it is not heavy like concrete tile; it does not rust like metal; it is lightweight, thereby solving structural problems caused by heavy roofing; it is an insulator; it does not react to heat; it does not conduct electricity; it is chemically inert; it resists corrosion; it is durable; it protects against temperature extremes in roofing material; it is readily obtainable and is cost-efficient.
In addition to its incorporation into roofing shingles, this miracle worker became part of other roofing materials such as caulking, flashing, cement, vents, felt, underlayment, roofing tar and asphalt liquids. Chrysotile asbestos was incorporated into sealants such as caulking and adhesives, which were easily injected into cracks and onto porous surfaces. Thus it can be found in chimneys, boilers, water pipes, roofs and exterior walls. Asbestos was used as a fireproofing component in boilers, furnaces and fireplaces, and to stop electrical contacts. It was valued for its pliability and was used in applications demanding high heat and as a sealant in high-pressure steam and gas lines. Look in your basement and examine the material wrapped around your heating pipes: It may be filled with asbestos fibers.
Roofing manufacturers incorporated two kinds of asbestos fibers into roofing materials: chrysotile or white asbestos, and amphibole, the latter being the more dangerous of the two. Amphibole fibers have sharp and spiny structures. Chrysotile fibers, also known as serpentine asbestos, are long, twisted and have soft edges.
In the home, until its use was banned, asbestos was widely used. Prior to the 1980s, and beginning in the 1940s, almost all sheetrock products used in the United States contained dangerous amounts of asbestos. Asbestos was valued because it lightened the weight of sheetrock, was durable and was fireproof. Most United States buildings constructed between 1950 and 1980 contain asbestos-based sheetrock.
It is not uncommon to find vinyl floor and ceiling tiles containing lethal amounts of asbestos fibers in homes today. Asbestos was used because it is fireproof, it increased tiles’ strength and durability, it made tiles easy to clean, it weighs less than petroleum asphalt tiles, it has insulating qualities that reduce heat loss and it absorbs sound. Most tiles have blends of both types of asbestos; some tiles are composed of as much as 50 percent asbestos. However, many ceiling tiles are composed of as much as 80 percent chrysotile, creating a “popcorn” effect—great for insulation and soundproofing.
Until the mid-1980s, asbestos fibers were used in vinyl wallpaper rolls to make the wallpaper sturdier, washable, strong, flexible and fire resistant, and to retain color and pattern indefinitely. This wallpaper weighed less, was a natural insulator and was inexpensive to produce.
As we now know, the use of asbestos presented grave dangers to those who manufactured and worked with asbestos-containing products. Although some insurance companies refused to insure asbestos workers as early as 1918 and physicians and other health professionals as early as the 1930s warned of the correlation between airborne asbestos fibers and deadly lung diseases, manufacturers knowingly continued to manufacture and to sell these products, thus allowing workers to continue to produce and to install them. For example, workers who installed, cut, taped and sealed sheetrock put themselves at risk because all of the products with which they worked contained asbestos fibers. Because there is an incubation period of perhaps 10 to 50 years before mesothelioma becomes manifest, workers are still becoming ill.
Thanks to the EPA and OSHA, in 1989 the Asbestos Ban and Phase Out Rule banned the incorporation of asbestos fibers in roofing products. Asphalt shingles are now reinforced with fiberglass or cellulose.
Asbestos incorporated into other products in the home is generally safe until it becomes old and brittle, becomes dust and is released as fibers into rooms and duct systems; thus, asbestos fibers in the air is especially dangerous in homes with forced-air heating systems when dried wallpaper and delaminated drywall crumble, releasing tiny inhalable particles. (Chrysotile asphalt fibers were mainly used in wallpaper.) Danger to home inhabitants also occurs when demolition occurs, when old asbestos-containing sealants are removed and when other asbestos-containing materials crumble. When sealants dry out, they become friable and microscopic asbestos particles become airborne and deadly.
Asbestos shards can lodge in the lungs, peritoneum and pericardium causing pleural, peritoneal and pericardial mesothelioma. These shards cannot be expelled, nor do they break down like organic compounds. The asbestos fibers lodge in the outer tissue linings of these organs in the thin layer of cells known as the mesothelium. The fibers inflame the surface of these membranes to produce scar-tissue plaques that become cancerous tumors.
Although it eventually became illegal to manufacture asbestos-containing products, it is sad to note that some stores continued to sell vinyl-asbestos wallpaper until they had exhausted their inventories.
If you suspect that any materials in your home contain asbestos fibers and you want to remove these materials, then hire professionals to do the work.
By Vivian J. Oleen
Vivian J. Oleen is an associate broker at Sopher Realty.