1. Level of exposure to substances, intensities of radiation etc. or other conditions considered to represent specified good practise and a realistic criterion for the control of exposure by appropriate plant design, engineering controls, and, if necessary, the addition and use of personal protective clothing.

2. In GBR, health-based exposure limit defined under COSHH Regulations as the concentration of any airborne substance, averaged over a reference period, at which, according to current knowledge, there is no evidence that it is likely to be injurious to employees, if they are exposed by inhalation, day after day, to that concentration, and set on the advice of the HSE Advisory Committee on Toxic Substances.