Officers who visited 10 night-clubs in the city found staff were exposed to music levels equal to an aircraft taking off or the sound of a pneumatic drill, for hours at a time.
Under the law, if noise levels in a workplace exceed 90 decibels, an employer must ensure staff wear ear protection. The assistant director of environmental services, Ian Coghill, said that in some night-spots the noise reached 115 decibels.
Now night-club owners face fines of up to pounds 5,000 or two years in prison under the Noise at Work Regulations 1989 if they do not protect their staff.
Mr Coghill said that out of the clubs visited, five owners had not bothered to check their noise levels, and of those that had, nothing had been done to protect staff.
He said: 'I can see that some night-club bosses and staff alike may see it as a bit of a strange idea that ear- muffs should be worn.' But he added: 'What seems harmless while the barperson is young can affect them greatly when they are older.'
Mark Jones, a director of Town and Country Inns which runs Stoodi Bakers, Bakers and Liberty's in Birmingham, said he was studying the report. 'It would look a bit silly to have staff walking around wearing ear- muffs, but if it is the law I suppose we will have to enforce it.' A spokesman for Orleans nightclub said: 'There is no way I can see any of our bar staff walking round with big woolly balls on their ears.'