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Another long-term risk factor from firefighting is noise-induced hearing loss (NIHL). NIHL is caused by exposure to sound levels at or above 85dBA according to NIOSH and at or above 90dBA according to OSHA. The time of exposure required to potentially cause damage depends on the level of sound exposed to. The most common causes of excessive sound exposure are sirens, transportation to and from fires, fire alarms, and work tools. Just by traveling in an emergency vehicle has shown to expose a person to between 103 and 114dBA levels of sound. According to OSHA, exposure at this level is acceptable for between 17 and 78 minutes. and according to NIOSH is acceptable for between 35 seconds and 7.5 minutes over a 24-hour day before permanent hearing loss can occur. This time period considers that no other high level sound exposure occurs in that 24-hour time frame. Sirens are usually outputting about 120dBA, meaning that according to OSHA, 7.5 minutes of exposure can occur and according to NIOSH, 9 seconds of exposure can occur before permanent hearing loss can occur.

dBA represents A-weighted decibels. dBA is used for measuring sound levels relating to occupational sound exposure since it mimics the sensitivity of the human ear to different frequencies. OSHA uses a 5-dBA exchange rate, which means that for every 5dBA increase in sound from 90dBA, the acceptable exposure time before a risk of permanent hearing loss occurs decreases by half (starting with 8 hours acceptable exposure time at 90dBA). NIOSH uses a 3-dBA exchange rate starting at 8 hours acceptable exposure time at 85dBA.

The average day of work for a firefighter can often be under the noise exposure limit for both OSHA and NIOSH. The average day of sound exposure as a firefighter is under the limit, but firefighters can be exposed to impulse noise, which has a very low acceptable time exposure before permanent hearing damage can occur due to the high intensity and short duration.

There are also high rates of hearing loss, often NIHL, in firefighters, which increases with age and number of years working as a firefighter. Hearing loss prevention programs have been implemented in multiple stations and have shown to help lower the rate of firefighters with NIHL. Other attempts have been made to lower sound exposures for firefighters, such as enclosing the cabs of the firetrucks to lower the siren exposure while driving. NFPA is responsible for occupational health programs and standards in firefighters which discusses what hearing sensitivity is required to work as a firefighter, but also enforces baseline (initial) and annual hearing tests (based off of OSHA hearing maintenance regulations). While NIHL can be a risk that occurs from working as a firefighter, NIHL can also be a safety concern for communicating while doing the job as communicating with coworkers and victims is essential for safety.. Hearing protection devices have been used by firefighters in the United States. Earmuffs are the most commonly used hearing protection device (HPD) as they are the most easily to put on correctly quickly. Multiple fire departments have used HPDs that have communication devices built in, allowing firefighters to speak with each other at appropriate sound levels, while lowering the hazardous sound levels around them.