Noise & Hearing Loss
Hearing loss is one of the most common work-related illnesses in construction and manufacturing. It builds up so slowly that most people don’t notice until it’s too late, and once it’s gone, it doesn’t come back. The good news: noise-induced hearing loss is almost completely preventable.
- Construction
- General Industry
How noise damages your hearing
Inside your inner ear are thousands of tiny hair cells that turn sound into signals for your brain. Loud noise bends and breaks these cells. A single very loud blast, like a gunshot or a powder-actuated tool, can damage them instantly. Years of everyday loud noise wears them down a little at a time. The body can’t grow new ones.
Noise-induced hearing loss usually hits the higher pitches first, the ones that make speech clear. That’s why people with early hearing loss say, “I can hear you, I just can’t understand you.”
Warning signs
- Ringing, buzzing or hissing in your ears after work (tinnitus)
- Hearing seems muffled at the end of the day
- Trouble following conversations in a noisy room or truck
- Turning the TV or radio up louder than others like
- Asking people to repeat themselves, or thinking people mumble
Temporary ringing or muffled hearing is a warning that permanent damage is starting. Tinnitus can also become permanent.
How loud is too loud?
| Sound | Typical level (dBA) |
|---|---|
| Normal conversation | 60 |
| Heavy traffic, a bulldozer at a distance | 85 |
| Skid steer, generator up close, belt sander | 90–100 |
| Circular saw, impact wrench, hammer drill | 100–110 |
| Jackhammer, chop saw, cut-off saw | 100–115 |
| Chainsaw | 105–120 |
| Powder-actuated tool, gunshot (impulse noise) | 140+ peak |
Actual levels depend on the tool, its condition, the material and the space. Hard, enclosed rooms such as stairwells, tanks and parking garages make noise louder.
The decibel scale is tricky
- Decibels are logarithmic. Every 3 dB increase doubles the sound energy reaching your ears.
- Distance helps. For a single noise source outdoors, doubling your distance cuts the level by about 6 dB.
- The 3-foot rule: if you have to raise your voice to be heard by someone an arm’s length away, the noise is probably above 85 dBA and you need hearing protection.
Exposure limits
Safe exposure depends on both how loud the noise is and how long you’re around it.
| Sound level (dBA) | OSHA permissible time per day | NIOSH recommended time per day |
|---|---|---|
| 85 | 16 hours | 8 hours |
| 88 | 10.6 hours | 4 hours |
| 90 | 8 hours | 2.5 hours |
| 94 | 4.6 hours | 1 hour |
| 95 | 4 hours | 47 minutes |
| 100 | 2 hours | 15 minutes |
| 105 | 1 hour | 5 minutes |
| 110 | 30 minutes | 1.5 minutes |
| 115 | 15 minutes | Less than 30 seconds |
- OSHA’s permissible exposure limit is 90 dBA averaged over 8 hours, with a 5 dB exchange rate: every 5 dB louder cuts the allowed time in half.
- NIOSH recommends a stricter limit of 85 dBA over 8 hours with a 3 dB exchange rate, which better matches how hearing is actually damaged.
- Impulse or impact noise should never exceed a peak of 140 dB.
Because the limits are averages over a shift, a few minutes with a loud saw can use up your whole day’s “noise budget.” Wear protection every time, even for short jobs.
Hearing conservation programs
In general industry, when noise averages 85 dBA or more over 8 hours, the employer must run a hearing conservation program. It includes:
- Noise monitoring to find out who is exposed, repeated when equipment or processes change. Workers can observe the monitoring.
- A baseline hearing test (audiogram) within 6 months of first exposure, then annual hearing tests, at no cost to workers.
- Follow-up on hearing changes. If a test shows a “standard threshold shift” (an average loss of 10 dB or more at the speech frequencies), the worker must be told in writing within 21 days, and the employer must refit or upgrade hearing protection.
- Hearing protectors in a variety of types, free of charge, with help fitting them. They’re required for anyone exposed at or above 90 dBA, and for workers at 85 dBA or above who have had a threshold shift.
- Annual training on how noise damages hearing, how to use protectors, and what the hearing tests mean.
- Records of noise monitoring and hearing tests.
Construction: OSHA’s construction rule (29 CFR 1926.52) uses the same 90 dBA limit and requires employers to use feasible controls, provide hearing protection, and run a “continuing, effective hearing conservation program” when noise exceeds the limit. It is less detailed than the general industry rule, but many contractors follow the general industry program as best practice.
Recordkeeping: a work-related hearing loss is recordable on the OSHA 300 log when an employee has a standard threshold shift and their overall hearing level is 25 dB or more above normal in the same ear.
Control the noise first
Hearing protection is the last line of defense. Under the hierarchy of controls, employers should reduce noise at the source first:
- Buy quiet: choose quieter tools and equipment, such as low-noise compressors and saw blades designed to reduce noise.
- Maintain equipment: fix mufflers, lubricate bearings, tighten loose panels and replace worn blades.
- Distance and barriers: put generators and compressors far from work areas, behind walls or berms, with exhausts pointed away.
- Enclosures: use enclosed, sound-insulated cabs on equipment, and keep the doors and windows closed.
- Scheduling: limit time near loud tasks and rotate workers.
Protect your hearing
- Wear earplugs or earmuffs whenever you’re around loud tools or equipment, even for “just a minute.”
- Learn to insert foam earplugs correctly: roll, pull, hold. A poorly inserted plug may block almost nothing. See Hearing Protection.
- For very loud work (above about 100 dBA), wear earplugs and earmuffs together.
- Choose protection you’ll actually wear all day. Comfort matters more than the highest rating.
- Put protection on before you start the tool, and keep it on until you’re out of the noise.
- Step away from noise when you aren’t using the tool, and turn off equipment that isn’t needed.
- Get your hearing tested if you notice any warning signs.
Tip: The number on the package (the NRR) is measured in a lab with a perfect fit. Real-world protection is usually much less. OSHA tells its inspectors to cut the NRR roughly in half to estimate real protection. A good fit beats a big number.
Other things that harm hearing
- Off-the-job noise adds up: hunting and target shooting, motorcycles, power tools at home, loud music through earbuds, concerts and sporting events.
- Some chemicals, including certain solvents (toluene, styrene, xylene), lead, mercury and carbon monoxide, can damage hearing on their own or make noise damage worse. See Solvents.
- Vibration and some medications can also play a role. Ask your doctor if you take medicines with hearing warnings.
Check the noise yourself
A professional sound level meter or noise dosimeter gives the most accurate results. The free NIOSH Sound Level Meter app for iPhone can give a reasonable estimate on the jobsite. If readings are near 85 dBA, ask your employer for proper monitoring.
Standards & references
- 29 CFR 1910.95: Occupational noise exposure (general industry)
- 29 CFR 1926.52: Occupational noise exposure (construction)
- 29 CFR 1926.101: Hearing protection (construction)
- 29 CFR 1904.10: Recording hearing loss cases
- NIOSH: Noise and hearing loss
Related: Hearing Protection · Hand-Arm Vibration · Hierarchy of Controls
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