Noise-induced hearing loss is permanent — and almost entirely preventable
Too much noise at work causes noise-induced hearing loss — permanent, irreversible, and one of New Zealand's most common work-related health conditions. WorkSafe's acceptable limits are 85 dB(A) averaged over 8 hours and a peak of 140 dB(C), both applying whether or not hearing protection is worn. If your workplace is likely to exceed these, you need a hearing conservation programme: control the noise at source first, and treat earmuffs as the last line of defence.
Loud noise destroys hearing cells that never grow back.
Exposure to hazardous noise damages and kills the receptor cells in the inner ear, causing hearing loss that is permanent and cannot be treated. It often develops gradually, so workers may not notice until the damage is done. Beyond hearing loss itself, noise is linked to tinnitus (ringing in the ears), communication difficulties, stress, and reduced safety because workers cannot hear warnings or vehicles. Because it builds up silently over years, it is easy to under-rate — which is exactly why it remains so common.
Two numbers define hazardous noise.
WorkSafe New Zealand sets acceptable workplace noise as no more than 85 decibels A-weighted, averaged over an 8-hour day (written LAeq,8h), and a peak sound level no higher than 140 decibels C-weighted. Both limits apply whether or not workers are wearing hearing protection — in other words, you cannot rely on earmuffs alone to meet them. As a rough guide, if you have to raise your voice to be understood about a metre away, noise is probably at a harmful level and warrants assessment.
Quieten the workplace first; protect the worker last.
| Control level | Examples for noise |
|---|---|
| Eliminate | Remove the noisy process; buy quieter machinery and tools at the design or purchasing stage. |
| Substitute / isolate | Use quieter equipment or methods; enclose or isolate noisy plant; move workers away from the source. |
| Engineering controls | Acoustic enclosures, silencers, damping, barriers and maintenance to reduce noise at source. |
| Administrative | Limit time spent in noisy areas, rotate tasks, schedule noisy work away from others, signage and training. |
| PPE | Properly selected, fitted and maintained earmuffs or earplugs — the last line, not the first. |
Relevant standards include AS/NZS 1269 (occupational noise management) and AS/NZS 1270 (hearing protectors). Source: WorkSafe NZ.
If noise is likely to exceed the limits, you need a managed programme.
A hearing conservation programme ties the pieces together: assess where noise is likely to exceed 85 dB(A) or 140 dB(C); have exposure (noise) monitoring done by a competent person such as an occupational hygienist; apply the hierarchy of controls; provide and train workers in hearing protection where needed; and arrange hearing tests (audiometry) so early changes are picked up. Workers must consent before taking part in hearing tests, and should be given their own results. Review the programme regularly and whenever the work or equipment changes.
General information, not legal advice. Noise requirements and standards can change. Confirm the current rules and exposure standards with WorkSafe NZ.
Audiometry detects damage early — and some hearing loss must be acted on.
Regular audiometry lets you spot early hearing changes before they become disabling, and check that your controls are actually working. Noise-induced hearing loss is a recognised form of work-related harm, so where monitoring reveals it, you must act on the result — reviewing controls and meeting any notification obligations that apply. The aim is always to prevent harm, not simply to record it.
Get a system that keeps your noise controls, monitoring and hearing checks in one place. Book a demo and we'll show you how it works — free 30-day trial included.
WorkSafe NZ sets acceptable noise as no more than 85 dB(A) averaged over an 8-hour day, and a peak of no more than 140 dB(C). Both limits apply whether or not hearing protection is worn.
No. Noise-induced hearing loss is permanent and cannot be cured, because it results from damage to the hearing cells in the inner ear. The good news is that it is almost entirely preventable with proper noise controls.
If noise at your workplace is likely to exceed 85 dB(A) over 8 hours or a peak of 140 dB(C), yes. That means assessing and monitoring noise, controlling it using the hierarchy of controls, providing hearing protection where needed, and arranging hearing tests.
No. Hearing protection is the last line of defence, not the first. Because the limits apply whether or not protection is worn, you must reduce noise at its source through elimination, quieter equipment and engineering controls, and use PPE to cover any remaining risk.
Audiometry is an important part of a hearing conservation programme because it detects early hearing changes, but workers must give consent before participating. They should also be given their own test results.
