What is Asbestos?

Asbestos is a mineral fiber that can be positively identified only with a special type of microscope. There are several types of asbestos fibers. In the past, asbestos was added to a variety of products to strengthen them and to provide heat insulation and fire resistance. Trained inspectors can supplement their knowledge with the information offered in this guide.

How Can Asbestos Affect Human Health?

We know that breathing high levels of asbestos fibers can lead to an increased risk of lung cancer in the forms of mesothelioma, which is a cancer of the lining of the chest and the abdominal cavity, and asbestosis, in which the lungs become scarred with fibrous tissue.

The risk of lung cancer and mesothelioma increase with the number of fibers inhaled. The risk of lung cancer from inhaling asbestos fibers is also greater if you smoke. People who get asbestosis have usually been exposed to high levels of asbestos for a long time. The symptoms of these diseases do not usually appear until about 20 to 30 years after the first exposure to asbestos.

Most people exposed to small amounts of asbestos, as we all are in our daily lives, do not develop these health problems. However, if disturbed, asbestos material may release asbestos fibers, which can be inhaled into the lungs. The fibers can remain there for a long time, increasing the risk of disease. Asbestos material that would crumble easily if handled, or that has been sawed, scraped, or sanded into a powder, is more likely to create a health hazard.

Where Would Asbestos Be Found, and When Can it Be a Problem?

Most products made today do not contain asbestos. Those few products made which still contain asbestos that could be inhaled are required to be labeled as such. However, until the 1970s, many types of building products and insulation materials used in homes contained asbestos.
Common products that might have contained asbestos in the past, and conditions which may release fibers, include:
  • steam pipes, boilers and furnace ducts insulated with an asbestos blanket or asbestos paper tape.
  • resilient floor tiles (vinyl asbestos, asphalt and rubber), the backing on vinyl sheet flooring, and adhesives used for installing floor tile.
  • cement sheet, millboard and paper used as insulation around furnaces and wood-burning stoves.
  • door gaskets in furnaces, wood stoves and coal stoves. Worn seals can release asbestos fibers during use;
  • soundproofing or decorative material sprayed on walls and ceilings.
  • patching and joint compounds for walls and ceilings, and textured paints.
  • asbestos cement roofing, shingles and siding.
  • artificial ashes and embers sold for use in gas-fired fireplaces, and¬†other older household products, such as fireproof gloves, stove-top pads, ironing board covers and certain hairdryers; and
  • automobile brake pads and linings, clutch facings and gaskets.
  • Houses built between 1930 and 1950 may have asbestos as insulation.
  • 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 wood-burning 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.

How to Identify Materials That Contain Asbestos

You can’t tell whether a material contains asbestos simply by looking at it, unless it is labeled. If in doubt, treat the material as if it contains asbestos, or have it sampled and analyzed by a qualified professional. A professional should take samples for analysis, since a professional knows what to look for, and because there may be an increased health risk if fibers are released. In fact, if done incorrectly, sampling can be more hazardous than leaving the material alone.

Keith Roe Asbestos Inspector Certification

References

1. “Asbestos: Facts and Tips for Home Inspectors and Homeowners” NACHI, https://www.nachi.org/asbestos.htm#sitemap-get-started.