Asbestos is a general name given to some types of naturally occurring minerals that can be found throughout the world in certain types of rocks. The asbestos found in these rocks can be separated into very fine and extremely durable fibers.
Due to its fire resistance, high tensile strength, poor heat and electrical conductivity, and being nearly impervious to chemical attacks, asbestos has proven to be well-suited for many uses in the construction industry. Asbestos gained wide-spread use because it is plentiful, readily available, and low in cost.
To be a significant health concern, asbestos fibers must be inhaled. Since the early 1900's modern knowledge has been capable of linking asbestos and a lung disease called asbestosis. In the 1970's, regulations were developed dealing with the manufacturing and removal of asbestos-containing materials and the massive asbestos mining efforts were abandoned. A reasonable substitute for asbestos could not be found for certain products leaving a few asbestos-containing products still being manufactured today.
Asbestos Containing Materials have been used in thermal insulation of pipes, duct work, boilers, and similar components. These thermal insulation materials tend to be more friable, meaning they can be crushed and reduced by hand, making the fibers air-borne. Surfacing materials containing asbestos. such as sprayed or troweled on acoustical ceilings, & sprayed on fireproofing also tend to be friable. Materials such as Transite, roofing felt, and floor tiles tend to be less friable & therefore pose less of a risk during the removal process.
While in place and in good condition, these Asbestos containing materials do not normally threaten exposure. Care must be taken when disturbing the asbestos containing materials in order to contain any fibers that will become airborne, as inhalation risk increases. When disturbing or removing these friable materials, containment precautions must be taken to prevent the fibers from escaping into the air.
The human body can not break down Asbestos fibers, which is why exposure can lead to negative health effects. Asbestosis is the buildup of scar tissue in the lungs that has formed around asbestos fibers. The scar tissue limits the ability of the lungs to expand and take in oxygen that the body needs to survive. This generally takes exposure to large doses of asbestos fibers and has a typical latency period of 15-30 years.
Mesothelioma is the more widely known and concerning disease related to asbestos exposure. Mesothelioma is a cancer of the chest or abdominal cavity. This cancer spreads rapidly and its physiological mechanism is still not fully understood. Mesothelioma does not have the dose or smoking relation and often takes 30-40 years after exposure to manifest. While advances in detection and treatment have been made, Mesothelioma is still often fatal with in six years of diagnosis.
To reduce the risk of contracting disorders from asbestos fibers, respirators, negative air machines, and protective clothing are used in conjunction with area containment, when asbestos containing materials are being worked on or removed. Accordingly, these processes along with sampling for identification have been standardized and are regulated by organizations like DHEC, AHERA, & OSHA to name a few. While low level exposures are not well established, there is still no known exposure limit.
In a situation needing removal of friable asbestos containing materials, along with the aforementioned containment and personal protective equipment, the taking and analyzing of air samples in and outside of the containment area are required to be performed. When renovations or demolition may include asbestos containing materials, an inspection and sampling of suspect materials is required before work can begin. Should suspect materials test positive for containing even 1% asbestos, removal should be performed by a licensed abatement contractor.