Following is some information from the Environmental Protection Agency regarding asbestos (www.epa.gov/asbestos)

Why Do You Need to be Concerned About Asbestos?

Asbestos is a mineral fiber that has been used commonly in a variety of building construction materials for insulation and as a fire-retardant. Because of its fiber strength and heat resistant properties, asbestos has been used for a wide range of manufactured goods, mostly in building materials (roofing shingles, ceiling and floor tiles, paper products, and asbestos cement products), friction products (automobile clutch, brake, and transmission parts), heat-resistant fabrics, packaging, gaskets, and coatings.

When asbestos-containing materials are damaged or disturbed by repair, remodeling or demolition activities, microscopic fibers become airborne and can be inhaled into the lungs, where they can cause significant health problems.

Examples of Where Asbestos Hazards May Be Found In The Home

• Some roofing and siding shingles are made of asbestos cement.
• Houses built between 1930 and 1950 may have asbestos as insulation.
• Attic and wall insulation produced using vermiculite ore, particularly ore that originated from a Libby, Montana mine, may contain asbestos fibers. Vermiculite was mined in Libby, Montana between 1923 and 1990. Prior to its close in 1990, much of the world's supply of vermiculite came from the Libby mine. This mine had a natural deposit of asbestos which resulted in the vermiculite being contaminated with asbestos. 
• Asbestos may be present in textured paint and in patching compounds used on wall and ceiling joints. Their use was banned in 1977.
• Artificial ashes and embers sold for use in gas-fired fireplaces may contain asbestos.
• Older products such as stove-top pads may have some asbestos compounds.
• Walls and floors around woodburning stoves may be protected with asbestos paper, millboard, or cement sheets.
• Asbestos is found in some vinyl floor tiles and the backing on vinyl sheet flooring and adhesives. 
• Hot water and steam pipes in older houses may be coated with an asbestos material or covered with an asbestos blanket or tape.
• Oil and coal furnaces and door gaskets may have asbestos insulation.