Occupational hearing loss is defined as damage to either or both ears, at the inner ear or auditory nerve, that results from an exposure in a person's occupation. Although high levels of noise are the main cause of occupational hearing loss (also called noise-induced hearing loss) there are also other factors in the work environment that can result in it. Chemicals, foreign bodies, vibration, barotrauma, along with other hazards can result in hearing loss. These losses that these workers obtain, affect many aspects of their life, mainly social interactions.

Within the United States of America, approximately 10 million people have noise-related hearing loss. Over twice that number are occupationally exposed to dangerous noise levels. Hearing loss accounted for a sizable percentage of occupational illness in 2007, at 14% of cases. As in many countries, in the US organizations like the Occupational Safety and Health Administration (OSHA) and the National Institute for Occupational Safety and Health (NIOSH) are working to understand the causes of occupational hearing loss and how it can be prevented. They work to produce regulations and guidelines to help protect the hearing of workers in all occupations.

Chemically-induced hearing loss (CIHL) is a potential result of occupational exposures. Certain chemical compounds may have ototoxic effects. Exposure to organic solvents, heavy metals, and asphyxiants such as carbon monoxide can all cause hearing loss. These chemicals can be inhaled, ingested, or absorbed through the skin. Damage can occur to either the inner ear or the auditory nerve.

Both noise and chemical exposures are common in many industries, and can both contribute to hearing loss simultaneously. Damage may be more likely or more severe if both are present. Industries in which combinations of exposures may exist include construction, fiberglass, metal manufacturing, and many more.

Certain medications may also have the potential to cause hearing loss.

It is estimated that over 22 million workers are exposed to dangerous noise levels, and 10 million are exposed to solvents that could potentially cause hearing loss every year, with an unknown number exposed to other ototoxic chemicals.