How noise harms hearing:

We’ve known for centuries that too much noise can cause hearing loss, says Richard Neitzel. He works at the University of Michigan in Ann Arbor. Some 200 years ago, accounts described blacksmiths who developed hearing loss from their constant hammering of metal.

Neitzel is an industrial hygienist, someone who studies how to keep people healthy at work. Most of what we know about noise and health, he says, comes from studying workers in loud jobs.

Science News: Too much noise can harm far more than our ears