For over two decades control banding has been used as a risk assessment and management tool for occupational health and safety issues. Control banding is implemented in areas where there is limited information on the severity and/or probability of a hazardous material exposure or isolated incident. The system is a qualitative approach to characterize and group workplace risks based on the available hazard and exposure information. Control banding was first applied in the pharmaceuticals industry as a means to identify control strategies for workers handling novel potent compounds. The process is now used in many industries and in diverse applications around the globe. More recently, control banding has been used for engineered nanomaterials, ergonomics, and injury prevention, as well as for environmental releases and consumer applications. Related methods include occupational exposure banding (OEB) to establish a range of permissible workplace exposure concentrations based on the health hazard category (e.g., where an OEL is not established or is otherwise lacking).
Applying control banding may be helpful when one or more of the following conditions exist:
- No occupational exposure limit (OEL) established for the material(s) of interest.
- Uncertainty or limited data available on health hazards (dose-response and toxicology).
- Lack of a validated method for workplace measurement or other challenges in exposure assessment.
- Other data gaps or uncertainties related to the severity and probability of an exposure or event.
Control banding relies on previous knowledge and the limited number of approaches to controlling occupational exposures to hazardous materials, despite the wide variety of materials, workplace applications, and risks. Here’s how it works – the hazards of a material or severity of an event are assessed following the procedure outlined in the model, and the most appropriate group or band is selected based on the defined categories and stratification criteria. Then, the probability or likelihood of workplace exposure is evaluated according to the model and assigned to a group or band. Based on these results, the risk level or control band is determined, with the model output typically indicating the recommended control strategies (e.g., general ventilation, local exhaust ventilation, enclosed ventilation, partial or full containment), or a specialist review. There are numerous models currently employed with differences in the intended use and application (e.g., for experts or use by non-EHS professionals/general practitioners), the complexity, number of bands, parameters included as inputs in the assessment, relative importance of each factor, criteria used for classification, and other design features. Results may vary depending on the model selected.
As with any method, it is important to understand the limitations of the overall approach and drawbacks to the specific model. Some criticisms of control banding include the need for better validation of models and operational analyses of implementation, and issues related to exposure variability and margins of safety. Control banding is largely qualitative, and its application can result in over-control or under-control errors.
Despite these limitations, where information is lacking or limited, a control banding framework can be used to provide a structured, standardized, and transparent process to assess and categorize the severity and probability of an exposure or event, and make risk management decisions (e.g., identify risk level and recommended controls). Control banding is not intended to replace the need for industrial hygiene expertise or quantitative measurements where applicable, but as another tool in our toolbox that can also be used in combination with other approaches.
Qualitative Risk Characterization and Management of Occupational Hazards: Control Banding. A Literature Review and Critical Analysis. US DHHS/CDC: NIOSH 2009-152, August 2009. http://www.cdc.gov/niosh/docs/2009-152/pdfs/2009-152.pdf
Michele Shepard, PhD, CIH