NIOSH Releases Materials on Call Center Noise Hazards

NIOSH research shows that workers at call and dispatch centers may face several hazards, including acoustic trauma from a sudden spike in noise levels and background noise from an incoming call.

Workers at call and dispatch centers may suffer health risks associated with high noise levels from their headsets. The National Institute for Occupational Safety and Health (NIOSH) has developed recommendations for prevention.

Millions of workers at call and dispatch centers in the United States use headsets during most of their workday. They mainly include dispatchers, medical transcriptionists, air traffic control specialists, customer service representatives, switchboard operators, reservationists, and bill collectors. Many work in high-pressure, stressful environments with noisy surroundings and poor ergonomic conditions. Although these other factors can pose additional health risks to workers, the scope of this document is limited to providing recommendations for reducing noise hazards.

NIOSH research shows that workers at call and dispatch centers may face several hazards:

  • Acoustic trauma from a sudden spike in noise levels (e.g., from feedback into the headsets or a sudden change in volume),
  • background noise from the incoming call, and
  • background noise and other stressors in the workplace.

Background noise in the workplace (radios played by other workers, conversations, noise from heating and air conditioning systems) or from the callers’ locations may cause workers to turn up the headset volume, resulting in sudden increase in noise levels transmitted into their ears. Some communication systems may experience feedback or interference that could cause spikes or squeals from the headset. Some workers complain of fluctuations in noise levels in the headset or having little control over headset volume.

The NIOSH recommended exposure limit (REL) for occupational noise exposures is 85 decibels. Exposures at or above this level are considered hazardous.

NIOSH has conducted several Health Hazard Evaluations (HHE) on workers who wear headsets for most of the workday, including FAA air traffic control specialists, emergency call center operators, and police station dispatchers. NIOSH has also conducted evaluations at several locations where medical transcriptionists work and at one fire department where emergency dispatchers work. Researchers interviewed workers, measured workers’ noise exposures, conducted area noise measurements, and measured sound levels from headsets using an artificial head fixture.

With the medical transcriptionists, the sound levels of the transcription recordings often varied even within a single dictation, forcing the transcriptionists to manually adjust the volume higher or lower. In some instances, the transcriptionists adjusted the volume to a higher or maximum setting to hear a low or quiet dictation, then the dictation levels or background noise spiked suddenly and was transmitted into their ears at those maximum levels. Researchers found that sound levels and high-frequency tones played at maximum volume resulted in equivalent sound levels under the headsets that were 4-18 dBA higher than the NIOSH recommended limit of 85 dBA. Thirteen of 21 transcriptionists (62 percent) interviewed reported having problems with the fluctuation in sound levels from the transcription communication equipment and headsets.

As for the 911 fire department dispatchers, background noise in the work area did not exceed the NIOSH REL (The median value of overall full-shift noise levels was 60 dBA). However, noise from loud alarms, visitors, and other distractions did cause the dispatchers to increase the volume on their headsets to mask the noisy environment. Although an examination of actual 911 recordings played through the headsets produced peak levels as high as 100 dB SPL at maximum volume, a review of the dispatchers’ audiograms showed no evidence of noise-induced hearing loss. How¬ever, repeated and prolonged exposure to such levels can cause hearing loss and ringing in the ear.

Overall, the NIOSH evaluations did not reveal hearing loss problems among call center operators and dispatchers that can be directly attributed to noise exposures from their headsets or the surrounding environment. However, most workers interviewed reported various symptoms often associated with prolonged exposure to high noise levels. Symptoms included ringing in their ears, headaches, irritability, increased tension, and fatigue.

NIOSH recommends that workers and employers at call centers take the following steps to protect against hearing damage and other adverse health effects:


  • Notify your supervisor and take protective action if you experience tinnitus (ringing in the ears), a dulled sense of hearing, or a fullness in the ears after a work shift or exposure to noise (that was not present before the exposure or work shift). This indicates an overexposure that, if repeated, will likely cause permanent effects.
  • Do not set the volume control above the middle point. The lower the better.
  • Ask to try different headsets with improved protection or noise-cancelling features.
  • Clean and maintain your headset periodically. Replace them when you notice damage or decreased performance.
  • Take advantage of breaks (in quiet areas) whenever possible.


  • Consider supplying communication systems with noise-limiting features.
  • Install noise controls to reduce background noise levels in the work environment, such as barriers between workstations or sound-absorbing materials on hard surfaces in the room.
  • Provide workers with a variety of communication headsets that offer adjustable volume controls, noise-limiting or cancelling features, and improved comfort and protection from ambient noise.
  • Establish a regular training program and educate workers about the proper use of headsets, communication equipment, and maintaining a quiet workplace environment.
  • Evaluate workplace exposure for noise levels above the NIOSH REL of 85 dBA and establish a hearing conservation program for exposed workers, including yearly hearing tests.

Click here to read the entire fact sheet.

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