To achieve harder metals that don’t wear down quickly, manufacturers are considering the use of tungsten-carbide nanoparticles and cobalt, which is thought to increase the strength and durability of the finished product.

Unfortunately, as Susanne Bastian et al’s article "Toxicity of Tungsten Carbide and Cobalt-Doped Carbide Nanoparticles in Mammalian Cells in Vitro" (Supplemental Material available here), demonstrates, increased exposure to these nanoparticles will, in all likelihood, lead to increased incidences of asthma, other respritory illnesses, and lung cancer among workers.

The good thing about studies like this is that, since nanomanufacturing is still in its infancy, there is time to make the necessary changes to the industrial environment that could lower the potential exposure of workers to these types of nanoparticles.