Background information
Last updated:2.1 BACKGROUND INFORMATION ON ASBESTOS
The name asbestos does not describe a single substance, but is a general term applied to various minerals, made up of long, thin separable crystalline fibres that possess very high tensile strength and flexibility. It is the physical characteristics of these fibres, coupled with their resistance to heat and chemical attack, which made them so useful.
For example it has been used to prevent the spread of fire in buildings, where it can be found in the construction of doors, partitions, as a screen (fire-curtain) in open roof spaces, as lagging around pipework, behind wall-mounted heating units, in ceiling and floor tiles and as external roofing and cladding. It can also be found in equipment, such as kilns, cookers, and fume cupboards. There are three main types of asbestos:
- Chrysotile (white)
- Amosite (brown)
- Crocidolite (blue)
There is considerable evidence to show that these three represent varying degrees of hazard. There are other types, but because they are less common, we rarely refer to them. Blue and brown asbestos are considered the most hazardous, but all types can cause fatal diseases.
(See Appendix 1 for a full glossary of terms used in this policy.) The danger from asbestos is caused primarily by inhalation of free fibres. Key health issues are:
Excessive exposure, either long term to low levels, or short term to high levels, can lead to fibrosis (scarring) of the lung tissue.
This scarring can continue to develop, even after exposure has ceased, leading to more serious lung damage, including cancer.
It can take up to 40 years after the last exposure for an asbestos related disease to develop.
It is not possible to detect by health or medical screening whether asbestos exposure has occurred until a disease develops, and there are no cures for asbestos related diseases.
Existing records of the location of asbestos in Council buildings are closed but retained centrally for specific reference purposes. Current records are maintained on a database. Records of asbestos material will be retained for a minimum of 40 years