The Control of Noise at Work Regulations 2005 (the Noise Regulations) came into force for all industry sectors in Great Britain on 6 April 2006. It's aim is to protect workers' hearing from excessive noise which could cause them to suffer from tinnitus - a permanent ringing in the ears - or loss of hearing altogether.
The regulations state that employers must provide hearing protection at a level of 85 decibels (daily or weekly average exposure). However, employers must assess the risk to workers' health and provide them with information and training when levels reach 80 decibels.
More information can be found on the HSE website here.
An estimated 20,000 people working during 2016 suffered from NIHL (Noise-Induced Hearing Loss).