Managing the unknown; the health risks of nanomaterials in the built environment

The application of nanomaterials, containing particles 1000 times smaller than the thickness of a human hair, is increasing but uncertainties persist regarding their potential health effects. An ongoing study to identify where nanomaterials are used in construction and to assess the impact of demolition processes on particle release has identified difficulties which arise when dealing with the unknown: assessing, and managing the risks of these, and other, new materials. The widespread use of materials whose risks are inadequately understood is clearly unsatisfactory. However, the timing of a detailed health evaluation for a new product or process is not straightforward - a focus on these aspects too early in a developmental lifecycle may derail potentially promising innovations. It is also necessary to carefully balance benefit and risk. A product with moderate risk potential may be tolerated provided there are significant benefits, and adequate control measures are available. Questions also arise regarding who should carry out and fund health risk assessments for new materials. Manufacturers clearly have responsibilities, but there are also advantages in centrally funded, objective assessment. Particular complications arise when assessing the health risks for nanomaterials in view of their wide variability and the lack of adequate exposure data. There is no requirement to label nano-enabled building materials. This makes it difficult to assess the extent of their usage, and hence also to determine the health risks to those working with them, or exposed to them due to demolition or recycling at the end of the product or building life. Manufacturers, researchers, governments and wider society share responsibility for addressing these challenges. However, there are steps which constructors can take in the interim to minimise the impact on those working with these uncertainties.