If you have to raise your voice to be heard by someone 3 feet away, the noise is probably around 85 decibels — the level at which the National Institute for Occupational Safety and Health (NIOSH) says hearing starts to be at risk at work. Its recommended exposure limit is 85 A-weighted decibels (dBA) averaged over an eight-hour workday; workers at or above it risk significant hearing loss over a working lifetime, though people differ in how susceptible they are.
Whether noise is hazardous depends on how loud it is, how long it lasts and how often it is repeated.
Louder means shorter
For every 3 dBA above 85, NIOSH recommends halving the daily exposure time — the exchange rate. Likewise, a workday longer than eight hours means a lower safe level.
For every 3 dBA increase, the allowable exposure time is cut in half. CDC/NIOSH.
| Level | You have to… | Typical sources |
|---|---|---|
| About 85–90 dBA | raise your voice to be heard 3 feet away | printing presses, lawn mowers, vacuums, power tools |
| 95 dBA or more | shout to be heard 3 feet away | bulldozers, ambulance sirens, chain saws, bars and nightclubs, large sporting events |
Other signs: ringing ears, or sounds that seem dull or flat after you leave; needing the car radio or phone louder at the end of a shift than at the start — and the radio seeming too loud the next morning. A sound level meter measures it; NIOSH makes a free Sound Level Meter app for iOS.
Who is at risk
Hazardous noise is present in every industry, most often mining, manufacturing and construction — but janitors and office staff in noisy workplaces are at risk too.
What employers should do
Preventing noise exposure is ultimately the employer's responsibility. NIOSH's hierarchy of controls, most effective first — often in combination:
| Control | Examples |
|---|---|
| Elimination | Remove the noise source |
| Substitution | Quieter equipment or tools |
| Engineering | Enclose the source in an insulated room; put a barrier between it and workers; put workers in a booth |
| Administrative | Schedule loud work when fewer people are around; rotate workers onto quieter tasks and give breaks; provide quiet break areas — without exposing more workers in the process |
| Hearing protection | When nothing else brings noise to a safe level, and whenever it exceeds 85 dBA, however briefly — chosen correctly and worn consistently |
Isolating noise doesn't reduce exposure to ototoxic chemicals — substances that damage hearing — in the same area.
What workers can do
- Take breaks from noisy work and spend less time in noisy areas.
- Keep radios and personal devices low, and use them only in quiet areas.
- Always wear hearing protection in noisy areas, and wear it as the manufacturer instructs.
Management, unions or workers can request a NIOSH Health Hazard Evaluation to find out whether a workplace has hearing hazards.
Sources
Based on "Noise-Induced Hearing Loss," National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention; a work of the United States government in the public domain.
Licence: CC0 1.0 (public domain) · Adapted from www.cdc.gov
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