The TUC web pages on noise and vibration have relevant information, including the Noise and vibration chapter of its health and safety guide, Hazards at work. See under noise and vibration in the health and safety section. tuc.org.uk/h_and_s
The Health and Safety Executive website has information on noise for employers and employees, including Noise at work - advice for employers and Protect your hearing or lose it! Advice for employees and statistics, guides, advice and examples of good practice. hse.gov.uk/noise
The Royal National Institute for the Deaf (RNID) runs an Employment, Learning and Skills Service for the deaf or hard of hearing and provides resources and information on protecting your hearing. The website provides a free online hearing check service.rnid.org.uk