Evaluation of the control banding method--comparison with measurement-based comprehensive risk assessment

The control banding method, or "control banding", is a simplified risk assessment system for chemical handling tasks. This system is supposed to provide assessment results of reasonable quality without expert involvement. The objective of this study was to evaluate the appropriateness of control banding judgment on the basis of workplace safety. A common approach for assessing workplace risk, which is called "comprehensive risk assessment" in this study, is to measure workers' exposure and compare it with relevant occupational exposure limits. Risk assessment was performed with control banding (COSHH Essentials, UK) at 12 workplaces of a petroleum company in Japan, where health risks had already been assessed separately through comprehensive risk assessment by experts and control technologies implemented accordingly. The obtained control banding judgments were then examined with regard to their adequacy by comparing them with existing control technologies. There was majority of cases (seven) where judgments by control banding were identified as "over-controlled"; there was no judgments identified as "under-controlled". Control banding also requested the seeking of expert advice in the majority of cases (eight). Thus, it was demonstrated that control banding tends to provide safe-sided judgment. A possible interpretation of this is that control banding is inherently designed to secure workplace safety by compensating for its insufficient exposure information with safe-sided judgment criteria and by requiring experts' intervention in high-risk cases. Control banding could be widely and effectively utilized in Japan, especially by employers in small enterprises, provided that the above characteristics are pre-acknowledged and health experts are made available. To this aim, it is essential to develop new local health experts and establish institutional mechanisms for facilitating employers' access to expert advice. It should however be noted that the number of workplaces evaluated in this study was small.