3.7.1 Definitions of Nanomaterials
This section is a summary of the information provided by Northwestern University’s Office for Research Safety on the safe handling and treatment of research quantities of nanomaterials. Interested readers should refer to that resource for additional details. “Engineered nanoparticles” are defined as laboratory-created particles with two or more dimensions between 1 and roughly 100 nanometers (nm) that are capable of being dispersed. “Industrial nanoparticles” are those associated with an industrial process (e.g. welding fumes) while engineered nanoparticles are produced to take advantage of their unique chemical and physical properties. These are further referred to as “bound” when dispersed into a solid matrix and not likely to become airborne, such as when part of a polymer matrix, and “unbound” when in aerosol or dispersed in a liquid matrix. All of the recommended safe work practices of the chemical hygiene plan apply for handling the matrix components of a nanomaterial in solution or as part of solid matrix.
3.7.2 Health and Safety
The toxic effects of nanomaterials vary with their size, shape, and composition, hence recommendations for their safe handling cannot be directly inferred from the results of studies on other nanomaterials. Given the limited information on the toxicity of nanomaterials, the recommendation is to assume the nanomaterials may be toxic and to minimize the use of nanomaterials in the unbound state to prevent ingestion, dermal and inhalation exposure. Given the limitations of our current understanding and the pace of research in this area, those working with nanomaterials are expected to periodically review the literature so they have the most recent data to guide their use of engineering controls and personal protective equipment. Surface deposited and aerosolized nanomaterials may not be visible to the naked eye, so it’s important to not rely on solely on visual cues to assess contamination or a release of material.
Engineering controls are necessary when manipulating potentially aerosolized nanomaterials. At a minimum, fume hoods should be used when weighing and handling small quantities of unbound nanoparticles. Moreover, it may be necessary to implement a HEPA filter on an exhausted enclosure, such as that found in modern biosafety cabinets, as an appropriate engineering control. Work with unbound nanoparticles outside of an exhausted enclosure or container should not be conducted without prior approval from the Director of Environmental, Health and Safety as aerosolized nanoparticles can reach the alveolar spaces of the lungs and remain airborne for days.
Other safe work practices include:
- Regularly wipe down work and potentially-contaminated surfaces with a wet cloth. Lab furnishings in the work area should be non-porous for ease-of-cleaning.
- Wear gloves when handling dry nanomaterials or those in a solvent matrix. Consult the solvent manufacturer’s safety data sheets or glove compatibility chart to choose the appropriate gloves for a project. Unbound engineered nanomaterials in a solvent matrix may present an additional dermal exposure hazard as the solvent may aid the transfer of a nanomaterial into skin cells.
- Decontaminate equipment that has been exposed to engineered nanomaterials prior to disposal or relocation. Post a decontamination form (available in the chemistry stockroom or through the Director of Environmental Health and Services) on the equipment prior to repairs or removal from the work space.
- Fill out hazardous waste tags with the words “engineered nanomaterials” in the chemical name field or the appropriate common name for disposal.
- Utilize NIOSH-approved N-, P-, R-100 (HEPA) respirators for protection from airborne nanomaterials.