The reporting of incidence where asbestos has been uncovered during renovation of a premises is still a frequent occurrence. While the majority of asbestos found hidden in the estimated half a million buildings around the UK is most likely to be chrysotile white asbestos, from time to time, other rare but more lethal forms of asbestos material can still come to light.

According to the Health and Safety Executive (HSE), early in 2010, building workers came across ‘brown asbestos’ while refurbishing a Wrexham nightclub. As is often the case, there was a lack of asbestos awareness by the premises owner and contractors to the deadly health risks posed by attempting to remove the material.

Discovering amosite ‘brown asbestos’ is unusual as this type of asbestos, along with crocidolite ‘blue asbestos’, was originally banned from use in 1985 by the introduction of the Asbestos (Prohibition) Regulations, before chrysotile ‘white asbestos’. Chrysotile continued to be used by the building industry in wall board / cement products, and sprayed surface coatings until prohibition began to be enforced from 1992 onwards.

For most of the twentieth century, right up until 1999, when the use and import of chrysotile was completely banned, different types of asbestos material were in use as a low cost heat insulator and fire retardant by many manufacturing, engineering and assembly plants across the north of England and the Midlands,as well as other industries such as shipbuilding and vehicle production.

There were six commonly used asbestos types in two defined groups – amphibole and serpentine.

The Amphibole group of asbestos consists of blue amosite and brown crocidolite, tremolite, actinolite and anthophyllite. This type was mostly used in heat resistant products such as pipe insulation, insulating board, sprayed asbestos coating, underfloor insulation and firedoors.

Amphibole asbestos fibres are sharp and straight and considered to be more dangerous because of their ability to pierce and permanently imbed themselves in the linings of the lungs after being inhaled.

The Serpentine group only contains chrysotile, considered less toxic than the Amphibole group but still can be a health risk if discovered in a worn and friable (disintegrating) condition. Chrysotile fibres are curly in appearance – hence the term ‘serpentine’- and was woven to make fireproof textiles such as fireblankets, oven seals and ropes. However, the the most common use was as a binding agent in liquids such as cement, plastic and resins to provide strength and stability to the mass production of cheap chemical resistant building materials such as roof sheets, cement board panels (AIB), floor tiles, guttering and roof tiles.

It has been estimated that as a result of the long gestation period of between 15 to 50 years from first inhaling the asbestos fibre dust until the first mesothelioma or asbestosis symptoms emerge, death from the incurable mesothelioma cancer from 1968 onwards was over 32,000, with the total fatality figure still increasing even as late as 2008 onwards to nearly 60,000.