Working in a school can damage your ears. According to the Belgium paper De Morgen, especially kindergarten teachers visit ear specialists on a regular basis. They often suffer from tinnitus.
The biggest cause of this hearing damage would be the high-pitched noises small children in large groups can make.
DEC recommends kindergarten teachers to always wear hearing protection, like for instance the Crescendo Office. The unique filters in the universal eartips (4 sizes available) reduce all sounds to an acceptable level, thereby limit the chance to develop hearing problems and reducing stress.