Engineered nanomaterials are those that are intentionally created (in contrast with natural or incidentally formed) and possess dimensions <100 nanometers. This definition excludes biomolecules (proteins, nucleic acids, and carbohydrates). Like most other laboratory chemicals nanoparticles may enter the human body through inhalation, skin exposure and ingestion. The specific hazards associated with most nanomaterials are yet to be identified in a systematic manner. Limited safety information available on such materials suggests that nano-sized particles are likely to be relatively more toxic than larger sized particulate matter. Owing to their reduced size and hence higher specific surface area, such materials have been found to be more reactive than higher sized particulate matter. Also, for the same reason nanomaterials are expected to be far more penetrable into the human body and hence can find their way to the body fluids (blood) and to specific organs more readily. Thus, if the material is toxic on its own, a higher level of toxic response is anticipated. Also, the nanoparticulate forms of some materials show unusually high reactivity, especially for fire, explosion, and in catalytic reactions.
In spite of the uncertainties on the nanomaterial hazards it is believed that the same general technical hazard control measures which are usually adopted for most chemicals may also be applied effectively for nanoscale materials. The Oak Ridge Institute for Science and Education (ORISE) a U.S. Department of Energy institute which focuses on scientific initiatives to research health risks from occupational hazards, prescribes, amongst other,the following work practices for nanomaterials:
- Transfer engineered nanomaterials samples between workstations (such as exhaust hoods, glove boxes, furnaces) in closed, labeled containers, e.g., marked “Zip-Lock” bags.
- Take reasonable precautions to minimize the likelihood of skin contact with engineered nanoparticles or nanoparticle-containing materials likely to release nanoparticles (nanostructures).
- If engineered nanoparticle powders must be handled without the use of exhaust ventilation (i.e., laboratory exhaust hood, local exhaust) or enclosures (i.e., glove-box), evaluate hazards and implement alternative work practice controls to control potential contamination and exposure hazards.
- Wear appropriate PPE on a precautionary basis whenever the failure of a single control, including an engineered control, could entail a significant risk of exposure to researchers or support personnel. Alternatively, ensure that engineered controls (e.g., laboratory chemical hoods) are equipped with performance monitors that will notify users if equipment malfunctions.
- Keep potentially contaminated clothing and PPE in the laboratory or change out area to prevent engineered nanoparticles from being transported into common areas.
- Consider any material that has come into contact with dispersible, engineered nanoparticles (that has not been decontaminated) as belonging to a nanomaterial-bearing waste stream. This includes PPE, wipes, blotters and other disposable laboratory materials used during research activities. Do not put material from nanomaterial-bearing waste streams into to the regular trash or down the drain.
- Evaluate surface contamination or decontaminate equipment used to manufacture or handle nanoparticles before disposing of or reusing it. Treat wastes (cleaning solutions, rinse waters, rags, PPE) resulting from decontamination as nanomaterial-bearing waste.
For more relevant information and guidance on preferred HSE practices for nanoscale materials the user may refer to the following document (from the US Department of Energy, Nanoscale Science Research Centres) on Approaches to Nanomaterials ES&H
(NSRC,Revision 3a,May 2 2008)
http://orise.orau.gov/ihos/Nanotechnology/files/NSRCMay12.pdf