What is Asbestos and Why does it pose so many problems?

All asbestos is a class 1 – carcinogen (cancer forming) material

Asbestos is the name for several silicate minerals which are highly fibrous with separable long thin fibres. The word asbestos is derived from a Greek adjective meaning inextinguishable. The Greeks termed asbestos the miracle mineral because of its soft and pliant properties, as well as its ability to withstand heat. Asbestos fibres are strong and flexible, having a tensile strength far greater than steel, yet flexible enough to be spun and woven. Due to asbestos being resistant to fire and heat, it is a poor conductor of electricity and has excellent thermal and acoustic properties and certain types being highly resistant to acids and alkalis. Asbestos has been widely used for many applications making it useful for a number of industrial and commercial uses.

The two main groups that asbestos is known as are:

Serpentine. (Chrysotile – white asbestos) Mineral or rock consisting mainly of the hydrous silicate of magnesia.

Amphibole.  (Amosite – brown asbestos & Crocidolite – blue asbestos) A group of minerals with similar crystal structures containing a silicate chain and combinations of chiefly sodium, calcium, iron and aluminum.

The most common types of these asbestos minerals are known as: - Chrysotile (White Asbestos), Amosite (Brown Asbestos), Crocidolite (Blue Asbestos), Anthophylite, Tremolite and Actinolite.
Asbestos became increasingly popular among manufacturers and builders in the late 19th century due to its resistance to heat, electricity and chemical damage, its sound absorption and tensile strength.

When asbestos is used for its resistance to fire or heat, the fibers are often mixed with cement or woven into fabric or mats. Asbestos was used in some products for its heat resistance, and in the past was used on electric oven and hotplate wiring for its electrical insulation at elevated temperature, and in buildings for its flame-retardant and insulating properties, tensile strength, flexibility, and resistance to chemicals.

Asbestos is known to cause serious illnesses, including malignant mesothelioma, lung cancer and asbestosis (also called pneumoconiosis).

White Asbestos

Chrysotile asbestosis obtained from serpentine asbestos rocks which are common throughout the world. Chrysotile asbestos fibers are curly as opposed to fibers from amosite asbestos, crocidolite asbestos, tremolite asbestos, actinolite asbestos, and anthophyllite asbestos which are needlelike. Chrysotile asbestos, along with other types of asbestos, has been banned in the United Kingdom and Europe. Chrysotile asbestos has been used more than any other type and accounts for about 95% of the asbestos found in buildings. Applications where chrysotile asbestos has been used are within corrugated asbestos cement roof sheets typically used for outbuildings, warehouses and garages. It is also found as flat sheets used for ceilings and sometimes for walls and floors. Numerous other items have been made containing chrysotile asbestos including brake linings, cloth (textile asbestos) behind fuses (for fire protection), asbestos pipe insulation, in floor tiles and in rope seals to boilers.

Brown Asbestos

Amosite asbestos, is a trade name for the amphiboles belonging to the Cummingtonite - Grunerite solid solution series, commonly from Africa, named as an acronym from Asbestos Mines of South Africa. One formula given for amosite asbestos is Fe7Si8O22(OH)2. It is found most frequently as a fire retardant in thermal insulation products and ceiling tiles.

Blue Asbestos

Crocidolite asbestosis an amphibole found primarily in southern Africa, but also in Australia. It is the fibrous form of the amphibole. One formula given for crocidolite is Na2Fe2+3Fe3+2Si8O22(OH)2. Notes: chrysotile asbestos commonly occurs as soft friable fibers. Asbestiform amphibole may also occur as soft friable fibers but some varieties such as amosite asbestos are commonly straighter. All forms of asbestos are fibrillar in that they are composed of fibers with widths less than 1 micrometer that occur in bundles and have very long lengths. Asbestos with particularly fine fibers is also referred to as "amianthus". Amphiboles such as tremolite asbestos have a crystal structure containing strongly bonded ribbon like silicate anion polymers that extend the length of the crystal. Serpentine (chrysotile asbestos) has a sheet like silicate anion which is curved and which rolls up like a carpet to form the fiber.

Other Asbestos Materials

Other regulated asbestos minerals, such as tremolite asbestos, CAS No. 77536-68-6,Ca2Mg5Si8O22(OH)2; actinolite asbestos (or smaragdite), CAS No. 77536-66-4, Ca2(Mg, Fe)5(Si8O22)(OH)2; and anthophyllite asbestos, CAS No. 77536-67-5, (Mg, Fe)7Si8O22(OH)2; are less commonly used industrially but can still be found in a variety of construction materials and insulation materials and have been reported in the past to occur in a few products.

Other natural and not currently regulated asbestiform minerals, such as richterite, Na(CaNa)(Mg, Fe++)5(Si8O22)(OH)2, and winchite, (CaNa)Mg4(Al, Fe3+)(Si8O22)(OH)2, may be found as a contaminant in products such as the vermiculite containing zonolite insulation. These minerals are thought to be no less harmful than tremolite asbestos, amosite asbestos, or crocidolite asbestos, but since they are not regulated, they are referred to as "asbestiform" rather than asbestos although may still be related to diseases and hazardous.

Amphibole Asbestos Group

Five types of asbestos are found in the amphibole group: amosite asbestos, crocidolite asbestos, anthophyllite asbestos, tremolite, and actinolite asbestos. Amosite asbestos, the second most likely type to be found in buildings, its uses include ceiling and wall panels, fire break bulkheads, moldings to safety glass, as linings to fire doors, asbestos cement sheets and pipes for construction, casing for water and electrical/telecommunication services.

This form of asbestos is more commonly know as asbestos insulation board (AIB). Amosite asbestos and crocidolite asbestos were formerly used in many products until the early 1980s. The use of all types of asbestos in the amphibole group has now been banned.