Asbestos is the generic term for a group of naturally occurring fibrous minerals with high tensile strength, flexibility, and resistance to thermal, chemical, and electrical conditions.

Asbestos is used in the manufacture of heat-resistant clothing, automotive brake and clutch linings, and a variety of building materials, including floor tiles, roofing felts, ceiling tiles, asbestos-cement pipe and sheet, and fire-resistant drywall. Asbestos also is present in pipe and boiler insulation materials and in sprayed-on or troweled-on surfacing materials on walls, ceilings, beams, crawlspaces, and between walls.

Asbestos fibers enter the body through inhalation or ingestion and become embedded in the tissues of the respiratory or digestive systems. Exposure to asbestos can cause numerous diseases, including asbestosis, an emphysema-like condition, lung cancer, mesothelioma, and gastrointestinal cancer. The symptoms of these diseases generally do not appear for 20 or more years after initial exposure.

Likelihood of exposure to airborne asbestos fiber is high in the following workplaces:

• Primary mining and manufacture of asbestos products.
• Secondary manufacture of asbestos containing products, such as fire-resistant clothing, fire-resistant wall board, roofing materials, brake and clutch parts, and asbestos cement pipe;
• Construction activities that include installation of "asbestos-containing materials" or the demolition, "removal", "disturbance" or alteration of asbestos containing building materials. Buildings constructed prior to 1981 may contain significant amounts of asbestos building materials. "Thermal system insulation", sprayed or troweled-on "surfacing materials", and vinyl or asphalt flooring installed before 1981 is particularly likely to contain asbestos.
• Shipbuilding
• Automobile brake and clutch repair activities.

Workers in the listed categories and those workers who are in the area where such activities are being conducted are particularly susceptible to exposure.

Custodial workers or other employees who perform housekeeping and clean waste, debris and accompanying dust in an area containing accessible thermal system insulation or surfacing material or visibly deteriorated Asbestos-Containing Material (ACM) /Presumed Asbestos-Containing Material (PACM) may be exposed.

Many small-scale "maintenance activities", repair, installation, or modification projects in buildings constructed prior to 1981 may cause exposure to workers. These activities include (but are not limited to) cutting into plaster walls to install or service electrical outlets, servicing lighting fixtures in ceilings, or cutting away insulation to work on pipes or heating system components. If these activities disrupt the matrix, crumble, pulverize, or generate visible debris from ACM or PACM (not to exceed an amount contained in a 60 inch by 60 inch glove bag), they are examples of Class III work under the construction standard.

The OHS asbestos standards require employers to take certain steps to guard against hazardous exposures to asbestos. These steps include:

• making an exposure assessment
• Have a Code of Practice developed.
• notifying employees about asbestos in the workplace, posting signs, establishing regulated areas
• providing employee training
• providing supervision by specially trained personnel
• providing protective clothing and equipment
• compiling records
• instituting medical surveillance of exposed workers.