Biomedical Engineering Reference
In-Depth Information
Gauntlet-type or polymer (e.g., nitrile) gloves with extended sleeves are required when handling
nanomaterials in their dry or liquid forms. It is important to note that the gloves should also be resis-
tant to the liquid chemicals that hold the nanomaterials. In addition, the gloves should be changed
frequently, as the penetration of and exposures to nanomaterials are not known to have good warn-
ing properties. Unlike nanomaterials, a skin burn sensation, such as from the exposure to strong
acid, is a good warning sign that exposure had occurred.
Spectacle-type safety glasses, with side shields, face shields, chemical splash goggles, and other
safety eyewear, should be worn appropriate to the type and level of hazard. Note that safety glasses
and face shields do not provide sufficient protection against airborne, dry nanomaterials.
2.5.4 f Ire aNd e xplosIoN c oNtrol
Airborne particles can cause fires and are explosion hazards when their concentrations are high
enough in the presence of oxygen and an ignition source. Nanomaterials have a substantially larger
surface-to-volume ratio than that of a same quantity of larger particles, and may, thus, present
a lower ignition energy, higher reactivity, combustion/catalytic potential, and combustion rate
(NIOSH, 2009a; Ostiguy, 2010). Therefore, relatively inert materials could become highly reactive
and combustible at the nanoscale. Many organic compounds, metal oxides, and some nonmetallic
inorganic compounds are potentially combustible, while aluminum, magnesium, zirconium, and
lithium are known to have high explosive potentials (Ostiguy, 2010). Recent studies show that the
minimum ignition energy of some nanomaterials is lower than the same material at a microscale.
In particular, metallic nanomaterials may display pyrophoric characteristics (e.g., aluminum begins
to burn on contact with air). However, several common nanomaterials, such as aluminum, iron,
zinc, copper, and several carbon nanomaterials, have been shown to have explosive characteristics
(maximum explosion pressure and rate of pressure rise) similar to conventional, microscale powders
(HSE, 2010; Steinkrauss et al., 2010). As a result, the authors concluded that nanomaterials may be
more prone to ignition, but, once ignited, the explosion violence is no more severe than microscale
powders. In general, the potential and severity of explosions increases with an increasing amount of
combustible nanomaterials. As a result, the risk of explosions at typical, laboratory-scale research
is smaller than that at pilot plants or full-scale production plants (NIOSH, 2012). According to
Ellenbecker and Tsai (2008), laboratory scale refers to working with substances in which the con-
tainers used for reactions, transfers, and other handling of substances are designed to be easily and
safely manipulated by one person. Storage of nanomaterials, however, potentially presents a case
where the quantity may be large and thus requires special attention to fire and explosion hazards.
Nevertheless, any nanomaterial-related activities should be carried out in ways that minimize the
release and airborne resuspension and in an environment that is isolated from an ignition source,
which could be an electrical, thermal, electrostatic, mechanical, or chemical source.
2.5.5 M aNageMeNt of N aNoMaterIal s pIlls aNd W aste
Cleanup procedures and kits should be developed and prepared in the case of nanomaterial spills.
In the case of significant spills (e.g., more than a few grams), it is prudent to activate emergency
response procedures. The key elements in the cleanup procedures include PPE (for minimizing the
inhalation and dermal exposures), containment, restricted access, and the removal of nanomaterial
spills. In addition, considerations should be given to potential complications due to the reactions
and compatibility between nanomaterials and cleaning materials; for example, inside the vacuum
cleaner filter and canister. Nanomaterial spills should be promptly contained by barricade tapes
or other barriers, walk-off mats placed at the entry points, and by reducing the amount of air cur-
rents passing over the surface of the spill area. Dry nanomaterials can be cleaned up using HEPA-
equipped vacuums and/or wet cleaning methods (e.g., moistened disposable wipes or humidification
of dry nanomaterials). Liquid spills containing nanomaterials can be cleaned up using absorbent
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