Types of asbestos

The hazard is the inhalation of respirable fibres that are too short and fine to be screened out by the body's natural filter mechanisms.

The risk depends on the type, friability (extent to which the fibres are bound into the matrix material), percentage content, condition, location and surface treatment or degree of physical protection.

Consider also other factors such as the age of and number of persons likely to be exposed and the likelihood of future damage or disturbance.

For most diseases the risk increases proportionally depending on the number of fibres inhaled progressively. Smokers are at far greater risk (see Appendix 3 of the Asbestos guidance note).

Is Blue the most dangerous form of asbestos and is White safe?

Because of its more durable and finer fibres, crocidolite (commonly known as 'Blue' asbestos) is generally considered to present a greater risk than the other two types of asbestos commonly found in buildings, namely amosite and chrysotile (commonly known as 'Brown' and 'White' asbestos respectively).

All things being equal, White is generally accepted as presenting a lower risk, but there is no recognised safe limit for exposure to any form of asbestos and all are a potential risk to health.

Scientific opinion differs on the degree of risk, if any, attached to White asbestos. Nevertheless in the UK the principal regulations, the Control of Asbestos Regulations 2012 (CAR 2012), apply to all asbestos irrespective of type with a single control limit for all asbestos.

See also Appendix 4 of the Asbestos guidance note.