Teachers are exposed to excessive noise more often than many industrial workers, the European Union's safety agency said.
Strict new regulations will mean that risks to health from noise will need to be cut to a minimum. And headteachers could face prosecution if noise levels rise to an average of 87 decibels over the day and they fail to take action.
Classrooms in Britain have an average noise level of 72 decibels, equivalent to standing next to a busy road junction. Researchers found that levels peaked for short periods at 112 decibels, as loud as a gunshot 20 feet away.
Professor Bridget Shield, from South Bank university in London, said:
"Teachers of particular subjects, such as music or design and technology, may be exposed to levels which could damage their hearing."
A music teacher in north-east Lincolnshire, who developed tinnitus following exposure to loud instruments, was awarded compensation of pound;40,000 after the National Union of Teachers took up his case.
Most staff would not be at risk, said Professor Shield, but classrooms are still noisy enough to affect children's performance and damage teachers'
In Hounslow, west London, schools are being soundproofed against noise from Heathrow jets. In the past, they have planned lessons around take-off times.
Les Carswell, deputy head of Lampton school, said: "Visitors notice the 10-second pauses when jets pass overhead, but staff and pupils don't. In terms of the long-term effects on health, who knows?"
Prolonged exposure to noise above 85 decibels can cause permanent loss of hearing. Noise is also associated with higher stress levels and damage to the voice.
Schools will be expected in future to conduct a risk assessment and introduce measures such as sound absorption or reduce teachers' exposure to noise if necessary.
The agency said it would be reasonable in its demands on schools, saying heads would have to work with health and safety officials in finding the right balance.
Professor Shield said: "Teachers have to raise their voices to be heard over the general noise for a large portion of the day. This contributes to ill-health."
The new regulations will come into force next February.