Current control banding approaches for nanotechnologies
Control banding (CB) is a qualitative risk management approach which can be defined as: “A strategy or process in which a single control technology (such as general ventilation or containment) is applied to a defined range or band of exposure to a chemical (such as 1-10 mg/m3
) that falls within a given hazard group (such as harmful by inhalation or irritating to respiratory system)” (Schulte et al., 2008
In general CB can simplify the decision-making process with regard to selection of control approaches. With the CB approach, it is not necessary for organisations to undertake the steps of worker exposure measurement and make comparisons with occupational exposure standards. This is undertaken by experts in order to inform the development of the CB guidance. CB includes the estimation of a specific hazard band for which a hazardous substance is assigned, based on risk statements (often from a Material Safety Data Sheet; MSDS) in combination with other factors, such as the volatility of the substance.
Underlying the CB approach is the R-phrase (risk phrase) for a substance, which links toxicological data with relative hazard from exposure to a substance via a given route of entry. R-phrases have been referenced and applied as guides in the absence of Threshold Limit Values (TLVs) or occupational exposure limits (OELs) for inhalation of very toxic substances. However it remains doubtful at this point whether specific R-phrases for nanomaterials have been developed to the extent to which they could be used dependably for this purpose.
In relation to nanotechnologies, CB is likely to be a suitable risk control approach for managing nanoparticle exposure in many situations. It is particularly favourable for the control of chemical hazards where there is limited toxicological information and workplace exposure limits are absent, as is currently the case with engineered nanomaterials. CB has therefore been presented as a viable approach to aid in the comprehensive evaluation occupational hazards.
Various CB-based tools are publically available, including:
Key literature relevant to the area is summarised below.