There are four main groups of SMF:

 Continuous Glass Filaments used in textiles, reinforced plastics and concrete, and as electrical insulation and plumbing materials.

 Fibreglass, glass fibre or glasswool used mainly in insulation mats. (Examples include ceiling insulation)

 Rockwool used in formed insulation, in limpet materials, such as acoustic insulation and fire-rating materials.

 Ceramic Fibres used as insulation blankets and for high temperature applications and fire-rated products.

The variety of different products used as SMF can results in a range of differing fibre diametres and chemical composition. It is in these range of chemical composition and fibre diamtre that health effects can be present. Typically glass fibres have higher fibre sizes and ceramic fibres have lower fibre sizes.*

For some years, there were concerns that SMF may be associated with health effects similar to those found with asbestos. This was because of the similarities of appearance, as well as the industrial application, of SMFs and asbestos. Now there is a large amount of scientific data from various studies, including epidemiological studies of workers in SMF industries. Reviews of these results show a number of health effects from exposure to various SMF.

Short term exposure can result in:

 Skin and eye irritation – more likely in workers having direct contact with SMF products for the first time or after a period of absence. May involve reddening, burning, itching, prickling, scaling, thickening and inflammation around the fingernails.

 Upper respiratory tract irritation – likely during exposure to very high concentrations of SMF in the air.

Long term exposure to SMF was shown to be associated with a slightly increased risk of lung cancer among exposed workers in early SMF industries. Animal studies have shown the potential of SMF to cause mesothelioma, but no cases of this lung disease were reported from studies in the fibreglass and rockwool manufacturing industries.

Animal studies and epidemiological results have led the World Health Organisation (WHO) and the International Agency for Research on Cancer to classify fibres such as rockwool, ceramic and glass fibre as Class 2B carcinogens. That is, they are possibly carcinogenic to humans.

With other cancer-causing substances (carcinogens), we know that there is no safe level of exposure -that is, there is no low level that can be guaranteed not to cause an increased cancer risk. However, Current scientific opinion is that SMF caused chronic health effects will not occur under typical “modern-day” operations, provided adequate precautions are taken in the workplace.

In particular fibrous dust is less easy to limit and control on construction sites and it is very important to ensure that workers in the construction, as well as the manufacturing, industry are protected from over exposure.