Design of measurement strategies for workplace exposures
- Correspondence to: Dr H Kromhout, Environmental and Occupational Health Division, Institute for Risk Assessment Sciences, University of Utrecht, PO Box 80176, Yalelaan 2, 3508 TD Utrecht, The Netherlands;
Measurement strategies for hazard control will have to be efficient and effective to protect a worker's health and well being. No measurement strategy for hazard control will ever be cost efficient in the short run when it is compared with the promises of tools such as the Control of Substances Hazardous to Health (COSHH) essentials (box 1): “a simple system of generic risk assessments which leads to the selection of an appropriate control approach”.1 Going straight to benchmark standards without the need of exposure measurements will certainly eliminate the cost of measurements. However, generic risk assessment tools like COSHH essentials and expert systems like the Estimation and Assessment of Substances Exposure (EASE)2 (box 2), as well as expert judgement by an occupational hygienist, are known to be inaccurate and they do not take into account the various components of variability in exposure levels (box 3). In fig 1, results of EASE estimates are compared with actual measured concentrations. From these pictures it can be seen that EASE estimates tend to be (1) higher than the measured concentrations, and (2) inaccurate especially at lower “true” concentrations (< 50 ppm and < 5 mg/m3). Nowadays, the latter exposures are being more relevant for workplaces of the developed world.
Box 1 Control of Substances Hazardous to Health (COSHH) essentials: easy steps to control chemicals
▸ Generic risk assessment tool aimed at controlling exposure and meet legal duties by a one stop approach
▸ Aimed at the employer
▸ Primarily focused at chemicals supplied for use at work
▸ Not meant for hazards arising from work activities (for example, wood dust, welding fumes, oil mists, etc), chemicals like pesticides and veterinary medicines, naturally occurring and biological hazards, and a few agents such as lead and asbestos with their own regulations