The Noise at Work Regulations 1989 and the Control of Noise at Work Regulations 2005 (the Regulations) are designed to minimise risk of occupational noise-induced hearing loss in the UK. The present study examined their effectiveness in a longitudinal field study, where participants were seen annually over a period of 3 years. Audiometric and otoacoustic emission measures were obtained in 154 recruits aged 18-25 years at risk of noise-induced hearing loss through occupational exposure and 99 non-exposed controls. The study had power to detect approximately 1-2 dB change per year, which is a smaller change than would be expected in the noise-exposed participants without protection. There were no significant effects on auditory function, or rate of change in function, of risk group when other potential explanatory variables were taken into account. Nor were there significant effects when contrasting exposed participants working in companies demonstrating relatively lower or higher compliance with the Regulations. Noise levels in exposed participants averaged approximately 88-89 dB(A) before accounting for hearing protection. The only significant effects on hearing demonstrated in the study were small effects of estimated social noise prior to the study, for example at nightclubs or from personal audio systems. Limitations of the study arise from the range of noise level encountered and the restricted duration of the study, which precludes showing longer-term effects. The companies involved in the study are not necessarily representative of the UK in terms of their compliance. Within these limitations, no evidence for lack of effectiveness of the Regulations was found. This report and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy. HSE Books