Biomedical Engineering Reference
In-Depth Information
2.5.2.4 Personal Hygiene
Good personal hygiene should also be practiced regularly where nanomaterials are handled to avoid
the migration of nanomaterials out of the workplace. In addition to the required PPE described in
the following section, hand-washing and showering facilities should be available and easily acces-
sible for the decontamination of workers, particularly before drinking, eating, smoking, and leav-
ing the workplace. To prevent carrying nanomaterials back home, it is necessary to provide locker
rooms and laundry services for the storage and decontamination of work clothes. Do not eat, drink,
or smoke in the areas where nanomaterials are handled.
2.5.3 p
ersoNal
p
rotectIve
e
quIpMeNt
Exposure controls by means of PPE should be considered on a precautionary basis, despite the limited
information on the effectiveness of PPE for the protection against nanoparticles. PPE include respira-
tors, clothing, gloves, glasses, and other garments designed to protect the workers by means of filtra-
tion, shielding, or a clean air supply. PPE should be considered as a last resort, when engineering and
administrative controls are unfeasible or unsatisfactory, to provide sufficient protection to the workers.
Specific PPE requirements should conform to the OSHA regulation 29 CFR Part 1910 Subpart I.
2.5.3.1 Respirator
An evaluation of the airborne exposure to nanomaterials by IH professionals is necessary to deter-
mine whether or not respirators are required. As a general guideline, activities that involve agitating
dry nanomaterials (e.g., cleaning, scooping, and pouring) or handling nanomaterials without effective
control measures are at a high risk of inhalation exposure, and, thus, require respiratory protection.
When respirators are required, the IH professionals are responsible for developing and implementing
a respiratory protection program (RPP) that includes the following key elements: respiratory selection
procedures, medical evaluation and fit testing, procedures and schedules for respirator cleaning and
maintenance, employee training, and program effectiveness evaluations. For more information about
the RPP, readers are referred to the NIOSH publications
Approaches to Safe Nanotechnology
(NIOSH,
2009a) and
Respirator Selection Logic
(Bollinger, 2004). A brief summary is provided below.
The respirator and, when applicable, cartridge should be selected according to the actual and
acceptable exposure levels. Thus, the desired protection factor will increase when the acceptable
exposure level is low and/or the actual exposure level is high. Ellenbecker and Tsai (2008) recom-
mended that, if it is required, the respirator should be at minimum a half-mask, P100 cartridge-type
respirator that has been properly fitted for the workers. In addition, disposable respirators with at
least an N95 rating are acceptable for workers not required to have respirators. However, Ostiguy
(2009) recommended against the use of negative-pressure respirators because a loose fit will result
in the penetration of nanomaterials into the respirator. This highlights that employee training on the
proper use of respirators is crucial in ensuring the effectiveness of the respirator.
Recently, the NIOSH has proposed recommended exposure limits (RELs) for airborne carbon
nanotubes and nanofibers (CNT and CNF), and nano titanium dioxide (TiO
2
) (NIOSH, 2010a,
2011b). With respect to 8-h, time-weighted average (TWA) mass concentrations, the REL is 7 μg/
m
3
of elemental carbon for respirable CNT and CNF, whereas it is 0.3 mg/m
3
for nano-TiO
2
. In
workplaces where the estimated exposure level exceeds the above REL, an RPP may be necessary.
OSHA shows that the assigned protection factor (APF) for fit-tested half/dust mask and elastomeric
half mask is 10, loose-fitting or hood-powered air-purifying respirator is 25, and elastomeric full
facepiece is 50 (OSHA, 2009a).
2.5.3.2 Protective Clothes, Gloves, and Other Equipment
The NIOSH has recommended that protective clothing normally required for wet chemistry labo-
ratory would be appropriate for the handling of nanomaterials until new information is available,
including close-toed shoes, long pants without cuffs, long-sleeved shirts, and laboratory coats.
