Asbestos

Sham S. Misri

What is Asbestos?

Asbestos is a mineral fiber that occurs in rock and soil.

Asbestos is a material which does not melt or catch fire when it is put into flames. It also helps to hold off heat because heat goes through it very slowly.

Because of its fiber strength and heat resistance asbestos has been used in a variety of building construction materials for insulation and as a fire retardant. Asbestos has also been used in 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.

Most uses of asbestos are not banned. A few are banned under existing regulations. Asbestos may be found in Attic and wall insulation, Vinyl floor tiles and the backing on vinyl sheet flooring, adhesives, Roofing and siding shingles.

Asbestos also finds its use in textured paint and patching compounds used on wall and ceilings, Walls and floors around wood-burning stoves protected with asbestos paper, millboard, or cement sheets, Hot water and steam pipes coated with asbestos material or covered with an asbestos blanket or tape, Oil and coal furnaces and door gaskets with asbestos insulation, Heat-resistant fabrics, Automobile clutches and brakes.

Other places where asbestos can be found:

•      Schools

•      Workplace

•      Soils and rock: naturally-occurring asbestos

•      Drinking water

•      Air: regulations

How Can People Be Exposed to Asbestos?

Asbestos fibres may be released into the air by the disturbance of asbestos-containing material during product use, demolition work, building or home maintenance, repair, and re modelling.

Health Effects from Exposure to Asbestos

Exposure to asbestos increases risk of developing lung disease. That risk is made worse by smoking. Disease symptoms may take many years to develop following exposure.

Three of the major health effects associated with asbestos exposure is:

•      Lung cancer

•      Mesothelioma, a rare form of cancer that is found in the thin lining of the lung, chest and the abdomen and heart

•      Asbestosis, a serious progressive, long-term, non-cancer disease of the lungs

Fire resistant asbestos cement sheets are made by mixing cement and asbestos fibres in water. Some pipes are also made from asbestos cement.

Most of world’s asbestos is mined in Canada and the Ural Mountains of Russia. It is often necessary to crush one hundred tons of rock to get five tons of asbestos.

Now we know that asbestos is heat resistant.

Did you know?

The heat resistance of asbestos has been known for many hundreds of years. King Charlemagne of France even had a table cloth of asbestos. When it became stained, it was just thrown into the fire to clean it, then pulled out and used again*.

[Ref.* Growing up with Science, Encyclopaedia of Invention P-102]