Asbestos

Asbestos

Asbestos

(from Greek

meaning "unquenchable" or

"inextinguishable") is a set of six naturally occurring silicate

minerals exploited commercially for their desirable physical

properties. They all have in common their asbestiform habit, long,

(1:20) thin fibrous crystals. The inhalation of asbestos fibres can

cause serious illnesses, including malignant lung cancer,

mesothelioma (a formerly rare cancer strongly associated with

exposure to asbestos), and asbestosis (a type of pneumoconiosis).

Since January 1, 2005, the European Union has banned all use of

asbestos

[1]

and extraction, manufacture and processing of asbestos

products.

[2]

For environmental samples, one must normally resort to electron

microscopy for positive identification.

[3]

However today

gravimetric and PCM/PLM techniques are employed, which cannot

readily identify the smallest, most hazardous, fibers. These

techniques being limited to PM10 particulate size evaluation which

completely ignores ultrafine particles (UFPs).

Asbestos became increasingly popular among manufacturers and

builders in the late 19th century because of its sound absorption,

tensile strength, and its resistance to heat, electrical and chemical

damage. When asbestos is used for its resistance to fire or heat, the

fibres 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.

Fibrous asbestos on muscovite

Asbestos

Asbestos

Contents

1 Types and associated fibres

1.1 Serpentine

1.1.1 White

1.2 Amphibole

1.2.1 Brown

1.2.2 Blue

1.2.3 Other materials

2 Producing nations

3 Uses

3.1 Historic usage

3.2 Recent usage

3.3 Specific product

Asbestos

-




Types and associated fibres 

 

Six minerals are defined by the

 

 

 

United States Environmental

Protection Agency as "asbestos" including that belonging to the serpentine class chrysotil

e and that

belonging to the amphibole class amosite, crocidolite, tremolite, anthophyllite and actinol

ite.

There is an important distinction to be made between serpentine and amphibole asbestos due

to

differences in their

chemical composition and their degree of potency as a health hazard when inhaled

Blue asbestos (crocidolite) from

Wittenoom, Western Australia. The

ruler is 1 cm.

3.3.1 Serpentine group

3.3.2 Amphibole group

4 Health problems

4.1 Other asbestos-related diseases

4.2 Asbestos as a contaminant

4.3 Environmental asbestos

5 History of health concerns and regulation

5.1 Before 1900

5.2 1900s–1910s

5.3 1920s and 1930s

5.4 1940s

5.5 1950s

5.6 1960s–early 1980s

5.7 Modern regulation

5.7.1 United States

5.7.2 New Zealand

5.7.3 Australia

6 Contamination of other products

6.1 Asbestos and vermiculite

6.2 Asbestos and talc

7 Asbestos in construction

7.1 Asbestos construction in developed countries

7.2 Asbestos construction in developing countries

7.3 Asbestos and 9/11

8 Litigation

9 Critics of safety regulations

9.1 EU-Canada dispute

9.2 Other criticism

10 Substitutes for asbestos in construction

11 Recycling and disposal

12 See also

12.1 Mineralogy

12.2 Other asbestos-related topics

13 References

14 Additional reading

15 External link