Nanotechnology involves the manipulation of nanometer length matter (one-billionth of a meter) to produce new materials, structures and devices. The U.S. National Nanotechnology Initiative (NNI) defines a technology as nanotechnology only if it involves all of the following:
- Research and technology development involves structures with at least one dimension in the 1-100 nanometer range.
- Creating and using structures, devices and systems that have new properties and functions because of their nanometer scale dimensions.
- Ability to control or manipulate on the atomic scale.
Nanostructured materials do not represent a new phenomenon. For example, the red and yellow hues in stained glass are the result of the presence of nanometer-sized gold and silver particles. However, the ability to probe, manipulate, understand and engineer matter at atomic scales has only recently become possibility In a 1959 lecture titled “There’s plenty of room at the bottom”, the Nobel laureate Professor Richard P. Feynman introduced the idea of a new and exciting field of research based on manipulating matter at the atomic level. At the time, Professor Feynman’s predictions were based on theoretical speculation. However, developments such as the invention of the Scanning Tunneling Microscope in 1981 have since made nanoscale science a reality. Nanotechnology is now a rapidly growing field of research and development that is cutting across many traditional boundaries.
More information on NIOSH’s nanotechnology research program can be found at the NIOSH Nanotechnology topic page. This is designed to be a robust source of information on NIOSH’s research program, with new information added as it becomes available. Additional information can be found on the National Nanotechnology Initiative (NNI)External website.
An increasing number of products and materials are becoming commercially available. These include nanoscale powders, solutions, suspensions as well as composite materials and devices containing nanomaterials. Nanoscale titanium dioxide is currently used in cosmetics, sun block creams and self-cleaning windows. Nanomaterials are increasingly being used in optoelectronic, electronic, magnetic, medical imaging, drug delivery, cosmetic, catalytic, and other applications. Nano-coatings and nano-composites are being used in a wide range of consumer products from bicycles to automobiles. Further details on existing products can be found hereExternal.
NIOSH is performing research to help answer questions that are critical for supporting the responsible development of nanotechnology in the United States and and the competitive global market. These questions include:
- Are workers exposed to nanomaterials in the manufacture and use of nanomaterials, and if so what are the characteristics and levels of exposures?
- Are there potential adverse health effects of working with nanomaterials?
- What work practices, personal protective equipment, and engineering controls are available, and how effective are they for controlling exposures to nanomaterials?
- NIOSH is addressing these questions through a program of multi-disciplinary research, communication, and partnerships with other agencies, organizations, and stakeholders.
NIOSH’s research role stems from its mission as the federal institute that conducts research and makes recommendations in occupational safety and health. For more than 30 years, NIOSH has led research to define and address occupational health concerns related to emerging technologies and workplace practices. To its research on nanotechnology and occupational health, NIOSH brings:
- Experience in defining the characteristics and properties of ultrafine particles (such as welding fume and diesel particulate), which have some features in common with engineered nanomaterials.
- Capability of conducting laboratory studies to determine advanced health effects laboratory studies.
- Historic leadership in industrial hygiene policies and practices.
- Close research partnerships with diverse stakeholders in industry, labor, the government, and academia.
NIOSH is working in partnership with other government agencies primarily through participation in the U.S. National Nanotechnology Initiative, a federal research and development program established to coordinate the multiagency efforts in nanoscale science, engineering, and technology. This initiative is managed within the framework of the National Science and Technology Council (NSTC). NIOSH is a member of the NTSC’s Nanoscale Science, Engineering, and Technology Subcommittee (NSET). Within that subcommittee, NIOSH co-chairs, with the U.S. Food and Drug Administration, the interagency Nanotechnology, Environmental and Health Implications (NEHI) Working Group.
By one estimate, there are 400,000 workers worldwide in the field of nanotechnology, with an estimated 150,000 of those in the United States [Roco et al. 2010]. The National Science Foundation has estimated that approximately 6 million workers will be employed in nanotechnology industries worldwide by 2020 (http://nano.gov/node/622External).
- Roco MC, Mirkin CA, Hersam MC  Nanotechnology research directions for societal needs in 2020: retrospective and outlook. Arlington, VA: National Science Foundation [http://wtec.org/nano2/External].
Nanomaterials that can be inhaled, ingested or can penetrate skin indicate a potential for exposure and present the possibility of potential health effects. Processes that lead to airborne nanometer-diameter particles, respirable nanostructured particles (typically smaller than 4 micrometers) and respirable droplets of nanomaterial suspensions, solutions and slurries are of particular concern for potential inhalation exposures.
Results from experimental animal studies with engineered nanomaterials have provided evidence that some nanoparticle exposures can result in serious health effects involving pulmonary and cardiovascular systems and possibly other organ systems. NIOSH researchers have conducted or participated in the following research activities that have determined that:
- Asbestos and carbon nanotubes (CNTs) affect similar molecular signaling pathways in cultured lung cells, with asbestos exhibiting greater potency
- Nano or ultrafine titanium dioxide (TiO2) causes pulmonary inflammation and neuro-immune responses
- Ultrafine TiO2 or carbon black causes more inflammation than fine TiO2 or carbon black on a mass-dose basis
- Dispersion of ultrafine carbon black nanoparticles in the lungs of rats following intratracheal instillation results in an inflammatory response that is greater than agglomerated ultrafine carbon black
- Pulmonary exposure to single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) in mice causes acute and chronic systemic responses associated with adverse cardiovascular effects
- SWCNTs, MWCNTs, and carbon nanofibers (CNFs) have equal or greater potency in causing adverse health effects in laboratory animals, including pulmonary inflammation and fibrosis, in comparison with other inhaled particles (ultrafine TiO2, carbon black, crystalline silica, and asbestos)
- CNTs are genotoxic and can transform lung epithelial cells after long-term, low-dose in vitro exposure
- Preliminary research has indicated that mice exposed to both MWCNTs and methylcholanthrene (a known cancer initiator) are significantly more likely to develop tumors than those exposed to just MWCNT alone. See NIOSH Science Blog.
An exposure assessment should review the process and material flow plans for the facility and identify tasks and workers that may be exposed to nanomaterials. Staff interviews and a preliminary walk-through of the facility should be performed to ensure that all activities and potential exposure pathways are identified prior to sampling. Information collected should include the potential magnitude, duration, and frequency of exposure during different job tasks, or at specific processes, and the amounts of materials being used. Current work practices and existing engineering controls should be evaluated.
Exposure assessment and control verification approaches can be performed with traditional industrial hygiene sampling methods that include the use of samplers placed at static locations (area sampling), samples collected in the breathing zone of the employee (personal sampling), and measurements with real-time direct reading instrumentation. An integrated sampling strategy should include the use of both direct reading instrumentation and filter-based samples. Direct-reading instrumentation can be used to data log particle concentrations Filter-based samples can be used to identify the nanomaterial of interest with electron microscopy and elemental analysis.
Identifying appropriate control methods depends on knowing the characteristics of the nanomaterial, how exposures to nanomaterials can occur in the workplace, what are the potential effects of workplace exposure to a given material, and how can exposures to nanomaterials be measured accurately and reliably.
Nanotechnology holds great promise for society, and occupational safety and health is no exception. Engineered nanomaterials may support the development of the following: high performance filter media, respirators, coatings in non-soiling/dust-repellant/self-cleaning clothes, fillers for noise absorption materials, fire retardants, protective screens for prevention of roof falls and curtains for ventilation control in mines, catalysts for emissions reduction, and clean-up of pollutants and hazardous substances. Nanotechnology-based sensors and communication devices may help empower workers during work-based emergencies so that they can take preventative steps to reduce their exposure to risk of injury. Their smallness of their size coupled with wireless technology may facilitate development of wearable sensors and systems for real time occupational safety and health management. Nanotechnology-based fuel cells, lab-on-chip analyzers and opto-electronic devices all have the potential to be useful in the safe, healthy and efficient design of work itself.