This guidance, written with respect to UK law, is addressed primarily to employers. It is accessible to non-specialists so that they can use it as an introduction to the design of inhalation exposure monitoring strategies. The procedures can be used to investigate employee exposure, by inhalation, to substances hazardous to health. They will help you investigate the nature, extent and control of employee exposure. Contents include: UK Legislative requirements; Exposure limits; Inhalation exposure monitoring; Approaches to inhalation exposure assessment and monitoring.