Health Implications of Silica in the Built Environment Congress, London, June 1998. Special Topic Issue: Indoor and Built Environment 1999, Vol. 8, No. 2

Respirable crystalline silica can cause silicosis. But does it also cause lung cancer? Although the risk of cancer in silicosis patients is more than double that in people without the disease, experts do not agree on whether silicosis is a necessary pre-cursor for the development of a tumour. In 1997 the International Agency for Research on Cancer (IARC) published a controversial report stating that crystalline silica inhaled in the form of quartz or cristobalite from occupational sources is carcinogenic to humans. The analysis of many epidemiological studies concluded that mining and quarrying have only minor effect in the development of lung cancer, but in manufacturing industries, notably those which entail high temperature processes, the effect is significant. If this report will be universally accepted it could have far-reaching implications for many industries, especially those concerned with the built environment. This issue gives the opinions of various experts, including some who were on the IARC working party, and therefore is an indispensable contribution for those interested in this controversial debate.