Asbestos is a generic term for a group of naturally occurring silicate minerals that are primarily in South Africa, Canada, and the Russia. Asbestos can appear in fibrous crystal form, and when crushed, separates into flexible fibers. Asbestos minerals have the following characteristics in common:

• Separate into smaller an smaller fiber bundles when disturbed or handled
• Resistant to heat, bacteria, and chemicals
• Great tensile strength and stiffness
• Excellent electrical and thermal insulator
• Very good noise insulator
• Resistant to the effects of friction and wear

Asbestiform minerals are divided into two groups based on their morphology:

• Serpentine Minerals: Serpentine minerals have a sheet or layered structure. Chrysotile is white with fine silky fibers. It accounts for over 90% of the asbestos used in the United States.
• Amphibole Minerals: Amphiboles have a chain like structure. Amphiboles include Amosite and Crocidolite, which are used in fewer applications, but can be found in pipe insulation and heat insulation materials.

The Environmental Protection Agency (EPA) has identified three categories for the purposes of evaluating asbestos-containing materials in buildings.

• Surfacing Materials: sprayed or troweled-on asbestos used for accoustical, fireproofing, or decorative purposes on ceilings, walls, and structural members.
• Thermal System Insulation: insulation used to inhibit heat transfer or prevent condensation on pipes, boilers, tanks, ducts, and various components of plumbing and HVAC systems.
• Miscellaneous Materials: floor tile, ceiling tile, adhesives, asbestos-cement products, window glazing, caulking, textiles, and roofing materials.

The major route of exposure from asbestos is through inhalation, although asbestos fibers may gain entry through ingestion. Asbestos fibers have no odor, and some fibers are small enough to be invisible to the naked eye.

Most information about asbestos related disease comes from studying workers in asbestos related industries, such as shipbuilding, boiler workers, insulators, and asbestos mining. Exposure to very high levels of airborne asbestos typical of asbestos trades prior to 1972 has been linked to the following diseases:

• Asbestosis: a chronic disease in which the lungs become scarred (fibrosis) as a result of biological reaction to the inhalation of asbestos fibers. Asbestosis results after exposure to high concentrations of fibers over a long period of time. Symptoms usually occur 15-30 years after the first exposure.
• Mesothelioma: the rarest of asbestos-related diseases, it is a cancer of the covering of the lung or lining of the chest or abdominal cavities. The disease is always rapidly fatal, usually within a year after diagnosis. There is a direct relationship between smoking and the risk of developing mesothelioma. Symptoms usually occur 25-30 years after first exposure.
• Lung Cancer: now responsible for roughly one-half of the deaths that occur from past asbestos exposures. The cancer usually begins as a tumor in the lower lobes of the lungs. The earliest symptom is usually a persistent cough or change in chronic cough. Later symptoms include loss of appetite, weight loss, pain, and general weakness.

Other cancers have been noted in a very small number of individuals who are occupationally exposed to asbestos. The cancers usually start out as tumors in the gastrointestinal tract. Contact the American Cancer Society for more information about asbestos-related cancers.

Smoking and Asbestos

Smoking in combination with asbestos exposure multiplies the risk for lung cancer in a synergistic effect. Asbestos workers are approximately 5 times more likely to develop lung cancer than the general population. Smokers are 10 times more likely to develop lung cancer than the general population. A person who works with asbestos and also smokes is likely to have a 90 times greater risk of contracting lung cancer.

The presence of asbestos alone in a building does not mean that the building occupants are necessarily endangered. As long as asbestos-containing materials (ACM) remain in good condition, exposure is unlikely.

OSHA regulations define exposure at or above the permissible (PEL) of 0.1 fibers per cubic centimeter for 30 or more days a year.

ACM that can be reduced to powder by hand pressure are considered to be friable. Friable materials are more likely to release fibers into the air where they can be of source of exposure. Some non-friable materials may become friable if they are cut, drilled, or damaged by water.

When damaged, building maintenance, repair, renovation, or other activities may disturb ACM, creating a potential hazard to building occupants. Fiber release may occur by fallout, contact, or re-entrainment, where ACM on a horizontal surface may become re-suspended from activities like sweeping.

Damage and Deterioration

When ACM degrades or is damaged, it may release asbestos into the air:

• Avoid physical damage or disturbing ACM on ceiling, pipes, or floors when moving furniture, equipment, or supplies.
• Do not hang plants or pictures from structures covered with ACM.
• Do not drill, sand, or scrape materials that contain ACM.
• Do not attempt to clean any material that appears to contain asbestos.
• Contact your supervisor immediately to arrange proper cleaning of any material that you suspect may contain asbestos.
• Cleanup of ACM should only be done using a High Efficiency Particulate Air (HEPA) vacuum and/or wet methods by properly trained personnel.

Floor Care

In order to minimize the potential for exposure to asbestos during floor care, the following practices are recommended:

• Never sand or scrape asphalt or vinyl flooring that contains asbestos.
• Always strip floor finishes using wet methods and the lowest abrasion pads possible. Always use speeds less than 300 revolutions per minute (RPM) and never use coarse black pads.
• Burnish or dry-buff asbestos containing flooring only when it has enough finish so that the pad cannot accumulate and store the ACM.
• Do not dust, dry-sweep, or vacuum dirt or debris in an area that contains damaged thermal asbestos insulation, surfacing or deteriorated ACM. Use only wet methods or HEPA filtered vacuums.