Asbestos is banned from use in Europe due to its known toxicological effects. The question as to whether certain industrial minerals either contain asbestos fibres or occur in an asbestiform habit, i.e. whether they are asbestos-like, is an understandable one, which attracted a lot of attention in the United States in the 1970s. The mineralogical aspect of this issue is complex and requires specialist expertise to be fully understood. Nevertheless, it is important to remember that IMA-Europe member companies use selective mining methods where necessary and implement the highest quality control standards to ensure that the industrial minerals they supply do not contain asbestos, as defined by European Directive 83/477/EEC, when analysed by conventional methods.
Asbestiform is a term that is used to describe the mineral habit of minerals that are formed in a particular state that resembles asbestos. The American Society for Testing Materials (ASTM) has defined asbestiform minerals as mineral fibre populations generally having the following characteristics when viewed by light microscopy: (1) many particles with aspect ratios ranging from 20:1 to 100:1 or higher (greater than 5µm in length); (2) very thin fibrils generally less than 0.5µm in width; and (3) in addition to the mandatory fibrillar crystal growth, two or more of the following attributes: (a) parallel fibres occurring in bundles, (b) fibres displaying splayed ends, (c) matted masses of individual fibres, and (d) fibres showing curvature.
The common asbestos minerals fit this description perfectly, but in addition they are characterised by having high tensile strength and pronounced durability. Some minerals such as gypsum, calcite, brucite, talc can, on rare occasions, occur in a fibrous habit that can be described as ‘asbestiform’. The minerals in this unusual habit do resemble asbestos, but they do not share the other physical and chemical properties of asbestos. In particular they do not have any of the toxicological properties of asbestos. This mineral habit is very uncommon and asbestiform minerals of this kind are a geological curiosity, mostly found in the mineralogical collections of enthusiasts. They therefore have no significant public health risk implications.
Finally, the term `asbestiform‘ has also been applied to minerals containing asbestos. This is a misuse of the term since `asbestiform' can only ever be used to describe a mineral habit. The correct term for this mixture is simply “containing asbestos”. Thanks to high standards of quality control and selective mining methods where necessary, the commercial industrial minerals supplied by IMA-Europe affiliated companies do not contain asbestos as defined by the European directive 83/477/EEC, when analysed by conventional methods. This statement is based upon verification by certified independent laboratories.