Asbestos Containing Materials in Your Home - November 19th 2010
Asbestos was a popular material used widely in construction and many other industries. If asbestos fibres are enclosed or tightly bound in a product, for example in asbestos siding or asbestos floor tiles, there are no significant health risks. Asbestos poses health risks only when fibres are present in the air that people breathe.
Asbestos is the generic name for a variety of fibrous minerals found naturally in rock formations around the world. Because asbestos fibres are strong, durable and non-combustible, they were widely used by industry, mainly in construction and friction materials. Commercial asbestos fibres belong in two broad mineralogical groups: serpentine (chrysotile) and amphibole (tremolite, actinolyte and others).
- Amphibole asbestos often contains more iron and resists acid and extremely high temperatures. Because of this, it has been heavily used in industrial furnaces and heating systems. However when inhaled, amphibole fibres stay much longer in the lungs than chrysotile fibres and they are more likely to inflict damage and cause disease, including cancer. Accordingly, amphibole asbestos has been drastically controlled and largely replaced.
- Chrysotile is the only serpentine asbestos that is found in almost all asbestos-based products available today and is the main form of asbestos still mined. Chrysotile is different from the amphiboles both structurally and chemically. It is generally accepted that chrysotile asbestos is less potent and does less damage to the lungs than the amphiboles.
How much asbestos is in a product does not indicate its health risk. If the asbestos fibres are enclosed or tightly bound in a compound, there is no significant health risk. One of the main problems with asbestos came from sprayed or "friable" (easily broken up) amphibole asbestos used in buildings until the 1970s. People working in construction, maintenance or in the renovation of older buildings should be particularly careful when handling this asbestos.
Sources of Asbestos
The risks are greatest for workers in industries which produce and use asbestos, such as mining and milling. In the past, workers in these environments were exposed to 100 - 1,000 times more asbestos than today's workers. Today's strict standards limit workers' exposure and the ban of most uses of amphibole asbestos have reduced the risks.
During renovations and repairs to older buildings, construction workers, tradespeople and other building maintenance workers may be exposed to very high concentrations of asbestos fibres. The environment and work methods of these occupations are more difficult to control than fixed workplaces, but most tradespeople are trained in the proper handling of asbestos-containing materials.
Negligible levels of asbestos fibres are found in the soil, water and air, both naturally and from man-made sources. Asbestos concentrations in the air in rural areas are about ten times lower than those in larger cities, which are about 1,000 times lower than levels accepted in today's asbestos-related jobs. With such low exposure, environmental risks are negligible.
Due to natural erosion, high concentrations of chrysotile asbestos fibres may be found in some raw water supplies. Conventional water treatment methods can substantially reduce asbestos levels and there is no evidence that swallowed chrysotile fibres are a health hazard.
Buildings and Homes
Because it is a valuable reinforcing, insulating and fire-proofing material, asbestos was used widely in construction materials such as insulation board, asbestos cement, and floor and ceiling tiles. These products are very dense and do not release significant amounts of fibres under normal use. However, fibres may be released if these products are cut or damaged.
Asbestos fibre concentrations in the air in buildings are usually about the same as in the air outside, and are not a significant risk. However, levels may be higher if friable asbestos materials are disturbed.
There is also concern about vermiculite insulation which may contain small amounts of amphibole asbestos, principally tremolite or actinolite. These amphibole fibres may cause health risks if disturbed. However, there is currently no evidence of risk to your health if the insulation is sealed behind wallboards and floorboards, isolated in an attic, or otherwise kept from exposure to the home or interior environment.
The Health Risks of Asbestos
Asbestos poses health risks only when fibres are present in the air that people breathe. How exposure to asbestos can affect you depends on:
- the concentration of asbestos fibres in the air;
- how long the exposure lasted;
- how often you were exposed;
- the size of the asbestos fibres inhaled; or
- the amount of time since the initial exposure.
When inhaled in significant quantities, asbestos fibres can cause asbestosis (a scarring of the lungs which makes breathing difficult), mesothelioma (a rare cancer of the lining of the chest or abdominal cavity) and lung cancer. The link between exposure to asbestos and other types of cancers is less clear.
Minimizing Your Risk
Construction and maintenance workers should avoid creating asbestos dust from scraping, brushing, rubbing or cutting damaged insulation. Insulation damage should be reported to the appropriate authority, such as the Occupational Health and Safety Manager. If you work in this area, determine whether asbestos is present before beginning work and take appropriate precautionary measures.
Public and commercial building owners should keep an inventory of asbestos-containing materials to inform users, authorities and contractors.
Homeowners should receive expert advice before removing materials that may contain asbestos. If you think your home may contain asbestos, check regularly for signs of wear or damage. However, you can't always tell just by looking at a material. If in doubt, have it analyzed by a qualified professional, who can be found by looking up experts in "asbestos abatement /removal".
If you must handle small amounts of damaged asbestos-containing materials, follow these steps:
- Keep other people and pets away, and seal off the work area;
- Wet the material to reduce dust, making sure it is not in contact with electricity;
- If possible, do not cut or damage the materials further and do not break them up;
- Clean the work area afterwards using a damp cloth, not a vacuum cleaner, and seal the asbestos waste and cloth in a plastic bag. Check with your local municipality on how to dispose of asbestos-containing waste;
- Wear appropriate protective clothing, including a single-use respirator approved by the National Institute for Occupational Safety and Health (NIOSH); and
- Wash or dispose of clothing and shower after finishing the job.
Experiences with Asbestos
As a restoration contractor, we are called out to damage incidents and need to determine quickly if the materials that are impacted by the damage event and must be manipulated or removed are containing asbestos. If we suspect so, we send a sample to the lab for analysis. The turn around time is usually one day, however it can be the same day if required.
The issue with asbestos is when the renovation or restoration activity has the potential to cause a release of asbestos fibres into the air where the occupants and/or workers suck them deep into their lungs. Sanding, grinding and demolition/removal activities are the highest risk activities.
It is NOT an issue if the material doesn't need to be disturbed. Every home built prior to approximately 1985 has asbestos in various building materials. It is not the obligation of the insurance company to remove all the asbestos from your home and replace it with new materials that do not contain asbestos when you have an insurance claim. Nor is it the obligation of the owner selling his property to remove all asbestos containing materials from their building just because the home inspector identifies that it exists.
There seems to be a move about, striking fear into the heart of buyers and sellers alike that the asbestos containing materials in homes they are wanting to buy/sell are dangerous and must be removed or it's presence will most certainly devalue the property. Virtually all older homes contain ACM (asbestos containing materials).
In summary, if you are renovating an older home, be safe.