Hi. I'm Adepeju Adesina, a graduate research assistant at the University of Minnesota School of Public Health.
This is a hands-on-activity on identifying occupational exposure bands of nanomaterials.
I developed this activity along with Dr. Pete Raynor from the University of Minnesota.
The objective of this activity is to illustrate the derivation of occupational exposure bands of nanomaterials.
To carry out this activity, you will need the National Institute for Occupational Safety and Health (NIOSH) occupational exposure
band chart based on the Globally Harmonized System for hazard classification and labelling.
Also, you will need the Safety Data Sheets (SDSs) of each nanomaterial. SDSs may be provided by the manufacturer,
the importer, or the distributor of the material. All SDSs are from Alfa Aesar in this case.
First, to determine the occupational exposure band of fullerene, buckytubes, or nanotubes, go to the hazard
identification section of the SDS, locate classification and codes of fullerene on the SDS.
Here, the codes are H315, which means that it causes skin irritation, H319, which means that it causes serious eye irritation,
and H335, implying that it may cause respiratory irritation.
H228 is a measure of its flammability but this is not considered in determining occupational exposure bands.
Using the H codes, place fullerenes/ nanotubes into an occupational exposure
band using the NIOSH GHS-based occupational exposure band chart.
Here, H315, H319 and H 335 fall under band C.
Therefore, the occupational exposure limit (OEL) range of fullerene/nanotube particles is
greater than 0.1 and less than 1 milligram per cubic meter.
Next, to determine the occupational exposure band of silicon carbide beta-phase nanopowder, go to the hazard
identification section of the SDS; locate the classification and codes of silicon carbide on the SDS.
Here, the codes are H351, which means that it’s a suspected carcinogen, H315, which means that its causes skin irritation,
H319, which means that it causes serious eye irritation, and H335, implying that it may cause respiratory irritation.
Using the H codes, place silicon carbide nanopowder into an occupational exposure
band using the NIOSH GHS based occupational exposure band chart. Here, H315, H319 and H335 fall under band C.
However, H351 falls under band E. Since band E is more protective than C, we place silicon carbide nanopowder in band E.
Therefore, the occupational exposure limit (OEL) range of silicon carbide nanopowder particles
is less than 0.01 milligram per cubic meter.
Next, to determine the occupational exposure band of cerium iron oxide, 20% in water, nanoparticle dispersion, go to the
hazard identification section of the SDS; locate the classification and codes of cerium iron oxide on the SDS.
Here, the codes are H360, which means that it may impair fertility or cause damage to unborn child, H315, which means that it
causes skin irritation, and H319, which means that it causes serious eye irritation.
It is important to note that the hazard-determining component of cerium iron
oxide is methoxyacetic acid, which was added as a nanoparticle stabilizer.
Using the H codes, place cerium iron oxide nanoparticle dispersion into an
occupational exposure band using the NIOSH GHS-based occupational exposure band chart.
Here, H315 and H319 fall under band C. However, H360 falls under band D.
Since band D is more protective than C, we place cerium iron oxide nanoparticle dispersion in band D.
Therefore, the occupational exposure limit (OEL) range of cerium iron oxide
nanoparticle dispersion particles is greater than 0.01 and less than 0.1 milligram per cubic meter.
Based on the respective bands and OELs of each of the three nanomaterials, priority of
evaluation for potential worker exposure will be assigned as follows:
silicon carbide nanopowder will be greater than cerium iron oxide nanoparticles,
while cerium iron oxide nanoparticles will have greater priority over fullerenes/nanotubes.
For silicon carbide nanopowder and fullerenes/nanotubes, the nano-scale objects are the primary health concern,
whereas, for cerium iron oxide nanoparticle dispersions, one of its components,
methoxyacetic acid, is the primary health concern.
This concludes the activity on occupational exposure banding. Thank you for watching.