Biomedical Engineering Reference
In-Depth Information
recommendations has specifically addressed nanomaterials. Only recently, the NIOSH has provided
an interim guidance for medical screening and hazard surveillance for workers potentially exposed
to engineered nanoparticles, with their recommendations as follows:
•
Take prudent measures to control exposures to engineered nanoparticles
•
Conduct hazard surveillances as the basis for implementing controls
•
Continue the use of established medical surveillance approaches
Therefore, it is prudent to conduct medical surveillances of workers exposed to nanomaterials
composed of chemicals for which there are existing OSHA standards or NIOSH recommendations
(N IOSH, 20 09b).
2.6 A QUALITATIVE RISK-BASED CONTROL AND MANAGEMENT STRATEGY:
CONTROL BANDING
Control banding (CB) is a qualitative risk assessment strategy that determines workplace risks and
subsequently offers control measures appropriate for the determined level of risk. The original CB
strategy was developed in the 1980s by IH professionals in the pharmaceutical industry to manage
risks from exposures to a large number of new chemical compounds without firm toxicological and
exposure data (Zalk and Nelson, 2008; NIOSH, 2009c). The uncertainties faced by the pharma-
ceutical industry resemble those encountered at the early developmental stage of nanotechnology.
CB is based on the assumptions that the level of risk is a function of the severity of hazard and the
probability of exposure, and there are a limited number of control measures available, despite the
numerous hazards that exist. Typically, the hazards and exposures are stratified into 2-5 different
levels, also known as “bands.” The two bands are then combined together, resulting into risk-strat-
ified control bands, in which the degree of control increases with an increasing risk. In essence, in
a context of uncertainty, CB intends to focus limited resources on exposure controls and describes
how strictly a risk needs to be managed (NIOSH, 2010b). With that in mind, CB strategies in recent
years have gained international attention for its relative robust, ease-of-use framework and solution-
oriented approach.
Currently, there are several CB tools available to advise on the control of nanomaterial expo-
sures, such as CB Nanotool (Paik et al., 2008; Zalk et al., 2009), Precautionary Matrix for Synthetic
Nanomaterials (http://www.nanotechnologie.admin.ch; Höck et al., 2008), ANSES's CB tool for
nanomaterials (http://www.anses.fr; ANSES, 2010; Riediker et al., 2012), Stoffenmanager Nano
(http://nano.stoffenmanager.nl; van Duuren-Stuurman et al., 2012), Guidance on Working Safely
with Nanomaterials and Nanoproducts (Cornelissen et al., 2011), and GoodNanoGuide (http://good-
nanoguide.org). A commentary article by Brouwer (2012) has compared and described the similari-
ties and differences among several CB tools. Below, we introduce the CB Nanotool developed and
evaluated by Paik et al. (2008) and Zalk et al. (2009), and implemented at the Lawrence Livermore
National Laboratory as the required risk assessment approach for all work with nanomaterials. This
brief introduction is intended to serve as guidance on developing control and management strategies.
In the CB Nanotool, the control band of a specific operation is based on the overall risk level
(RL) determined for that operation. The RL is the result of a combination of the hazard severity
score and the exposure probability score. The factors that determine the severity score are selected
to take into account the physicochemical (40 points) and toxicological (30 points) characteristics
of the nanomaterial, and the toxicological characteristics (30 points) of their parent material. They
include the nanomaterial's surface chemistry, shape, diameter, solubility, the nanomaterial's as well
as their parent material's dermal toxicity, carcinogenicity, mutagenicity, asthmagen, reproductive
toxicity, and OEL. The factors that determine the probability score include the estimated amount
of chemical use (25 points), the dustiness/mistiness (30 points) of the nanomaterial, the number of
workers with similar exposures, and the frequency and duration of operation (45 points). If a factor
