NIOSH research has shown that some nanoparticles, including certain types of carbon nanotubes and metal oxides, can be toxic to the heart and lung in mice and rats in laboratory experiments. Other research has demonstrated various other adverse effects of nanoparticles. Through its Approaches to Safe Nanotechnology, NIOSH recommends that specific precautions be taken to protect workers who might be exposed to any level of nanoparticles or nanoparticle-containing materials. A big question left unanswered is, can nanoparticles cause the same types of disease in humans?

Multi-walled carbon nanotubes, known as MWCNTs for short, are a type of engineered nanomaterial that shows promise for various applications. These include the potential for creating stronger, more durable building materials; improving cancer therapies; creating more efficient means of energy generation, storage, and transmission; and speeding computer processes. However, as with other types of engineered nanomaterials, the potential occupational health implications of MWNCTs are not well understood at this emergent stage of the technology. A broad group of health and safety practitioners and business observers have agreed that research is vital for determining if MWCNTs pose a health risk for workers engaged in their production and industrial use, and for informing the responsible development of this technology. There is general agreement that this issue must be approached in a proactive manner with good research in order for society to benefit from the many promises this new class of materials has to offer.