Safety hazards with nanomaterials vary based on the composition of the materials. However, a few general observations are possible. For flammable or combustible solids (e.g. some metals), nanoscale materials could present a higher fire-explosion risk compared to coarser particles of the same material14. Decreased particle size can increase the combustion potential and combustion rate, and reactive/catalytic properties can exist at nanoscale that do not exist at larger scales. Gold is relatively inert as a macromolecule, but gold nanoparticles can catalyze the conversion of carbon monoxide to carbon dioxide.

The greater activity of nanoscale materials forms the basis for research into nanoenergetics. For example, nanoscale thermite powders composed of aluminum and molybdenum trioxide ignite more than 300 times faster than corresponding micrometer-scale material15.

14Health and Safety Executive. Horizon scannon information sheet on nanotechnology. Sudbury, Suffolk, United Kingdom: Health and Safety Executive. (2004).

15Granier JJ and Pantoya ML. Laser Ignition of Nanocomposite Thermites.Combustion Flame 138:373-382 (2004).