THE SHORT ANSWER
Two features of the rating method explain nearly every disappointing hearing loss result in California. The first 25 decibels are free — the Guides subtract a 25 dB “low fence” before calculating anything, so a worker with a genuine, measurable, permanent 25 dB noise-induced loss rates zero. And your better ear counts five times more than your worse ear: the binaural formula is (5 × better ear + worse ear) ÷ 6, so a worker who is functionally deaf in one ear and normal in the other rates far lower than intuition suggests. Both are real rules, not evaluator choices.
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In thirty seconds
- The first 25 decibels are free. The Guides subtract a 25 dB “low fence” before calculating anything, so a real, permanent, measurable loss below that threshold rates zero.
- Your better ear counts five times more than your worse ear. Total deafness in one ear with a normal other ear rates about 6% whole person.
- Ask for your employer’s annual hearing conservation audiograms — they usually show exactly when the shift happened. The date of injuryDate of injury For a cumulative or occupational disease claim, the law sets it as when you first suffered disability and knew or should have known it was work-related — not when the wear began. Almost every deadline runs off this. is often much later than the exposure, so a claim that feels too late frequently is not.
Understanding the two rules above is the difference between an informed decision and a bad surprise. What follows is the arithmetic step by step, what tinnitus adds and when, the two things the audiogram never captures, how the claim itself works, and the apportionmentApportionment Dividing permanent disability between industrial and non-industrial causes. It is to disability, not to findings on an image. fight you should expect.
How the calculation actually works
| SITUATION | RESULT |
|---|---|
| 25 dB average loss, both ears | 0% |
| 40 dB average loss, both ears | 22.5% binaural → about 8% whole person |
| Total deafness one ear, normal other | About 16.7% binaural → about 6% whole person |
| Total deafness, both ears | 100% binaural → 35% whole person |
Five steps
- Average four frequencies. Pure-tone, unaided, at 500, 1,000, 2,000, and 3,000 hertz, each ear separately. Those four were chosen because most speech energy sits there.
- Subtract 25 decibels. This is the low fence. The Guides treat losses below it as producing no practical hearing impairment.
- Multiply the remainder by 1.5%. That produces monaural hearing impairment for that ear. The scale tops out at 100% monaural at approximately 91.7 dB.
- Combine the ears, weighted: (5 × the better ear’s percentage + the worse ear’s percentage) ÷ 6.
- Convert to whole person. Complete binaural hearing loss converts to 35% whole person impairmentWPI — Whole Person Impairment The percentage from the AMA Guides that a rating is built from. Extremity percent is not whole person percent: 100% upper extremity = 60% whole person, 100% lower extremity = 40%. This is the most common source of confusion in a rating.. So binaural hearing impairment is multiplied by roughly 0.35 to reach whole person.
The second and third rows are where the felt injustice lives. Losing an entire ear rates about 6% whole person, because the formula assumes the good ear does most of the work. That is defensible as a statement about speech comprehension in quiet and indefensible as a statement about what it is like to lose directional hearing, work in noise, or use a telephone.
Tinnitus
Up to 5% may be added — but only when tinnitus accompanies measurable hearing loss and interferes with activities of daily living.
That second condition is the one that gets left out. Tinnitus that disrupts sleep, concentration, or the ability to work in a quiet environment is an ADL interference and should be documented as such. Tinnitus mentioned in passing in a history is not.
And the first condition is a hard limit. Tinnitus without measurable hearing loss gets nothing under the strict method. That is a genuinely difficult outcome for workers with severe tinnitus and preserved audiograms, and it is where an Almaraz/GuzmanAlmaraz/Guzman The doctrine permitting a physician to depart from the strict AMA rating where it does not accurately reflect the impairment, using another method inside the “four corners” of the Guides. analysis has to be built deliberately rather than asserted.
What is missing from the method
Two things the audiogram does not capture, and both are worth raising.
THE FREQUENCIES ABOVE 3,000 HZ
Noise-induced hearing loss characteristically damages 4,000 and 6,000 Hz first — the classic “noise notch.” The rating formula does not include those frequencies at all. A worker with a textbook noise notch at 4,000 Hz and preserved thresholds at the four rated frequencies has documented, permanent, occupationally caused damage and a rating of zero.
SPEECH DISCRIMINATION IN NOISE
The rating uses pure tones in a quiet booth. The complaint is almost always “I can’t follow a conversation when there’s background noise,” which is a different measurement and is not part of the method.
Neither of these is a defect in your case. Both are limits of the instrument, and both are the kind of thing a physician has to explain on the record if a strict rating is going to be challenged as failing to capture the impairment.
The claim itself
Occupational hearing loss is almost always a cumulative traumaCT — Cumulative trauma Injury from repeated exposure over time. The largest injury category in California and the least claimed. claim, which changes the deadlines and the identity of the defendants.
The date of injury is set by § 5412 — when the worker first suffered disability and knew, or reasonably should have known, that it was work-related. In a hearing loss case that is frequently much later than the exposure, and the date drives everything.
The law limits liability to the last year of injurious exposure in most cases, which determines which employer and which carrier are on the claim. For a worker with thirty years across six employers, that rule is the whole fight over who pays.
And this is the most common reason a valid hearing loss claim fails: the worker assumes it is too late because the noise exposure ended a decade ago. That is frequently wrong.
Apportionment
Expect: age (presbycusis), recreational noise, firearms, motorcycles, diabetes, ototoxic medication, and genetics. Presbycusis is real and it is the argument you will get. Two responses matter.
THE TWO LOSSES LOOK DIFFERENT ON THE AUDIOGRAM
Presbycusis is characteristically a sloping high-frequency loss without a notch. Noise-induced loss characteristically produces a notch at 4,000 to 6,000 Hz with recovery at 8,000 Hz. That distinction is visible on the audiogram, and it is where these cases are actually decided.
SERIAL AUDIOGRAMS ARE THE BEST EVIDENCE IN THE CASE
Where an employer conducted the hearing conservation program required by Cal/OSHA, there is a baseline audiogram and annual audiograms in the employer’s file showing exactly when the shift occurred. Those records should be requested in every case. Where the employer failed to run a hearing conservation program at all, that absence is itself significant.
Under EscobedoEscobedo The en banc decision requiring an apportionment opinion to explain how and why. A percentage without reasoning is not substantial evidence., an apportionment opinion still has to explain how and why — a percentage assigned to “age” without reference to the audiometric configuration is not substantial evidenceSubstantial evidence The standard a medical opinion must meet to support a finding..
Who this happens to
| INDUSTRY | THE NOISE |
|---|---|
| Construction | Framing, demolition, concrete, jackhammer and saw work |
| Manufacturing and metal fabrication | Stamping, press, grinding |
| Aviation | Ramp, ground crew, maintenance |
| Rail and transit | Yard and trackside operations |
| Longshore and terminal operations | Container and terminal equipment |
| Firefighters and law enforcement | Sirens, apparatus, range |
| Musicians, sound engineers, and venue staff | Sustained amplified exposure |
| Agriculture | Equipment and processing |
| Landscaping | Blowers, mowers, chainsaws |
| Nightclub, bar, and event staff | Amplified music across full shifts |
Frequently asked questions
I definitely have hearing loss but my rating is zero. How?
Because the Guides subtract 25 decibels before rating anything. A real, permanent, measurable loss below that threshold produces no impairment rating.
I’m deaf in one ear.
That rates about 6% whole person, because the formula weights your better ear five times more heavily. It is a real rule and it is the most counterintuitive number in this area.
My audiogram shows a notch at 4,000 Hz.
That is the classic signature of noise-induced hearing loss — and 4,000 Hz is not one of the four frequencies the rating formula uses. It is strong evidence of causation and it contributes nothing to the number.
Does tinnitus count?
Up to 5% may be added, but only where it accompanies measurable hearing loss and interferes with activities of daily living. Both conditions have to be documented.
I stopped working in noise ten years ago. Is it too late?
Probably not. The law sets the date of injury when you first had disability and knew, or should have known, it was work-related, which is often much later than the exposure.
They say it’s just my age.
Age-related and noise-induced loss look different on an audiogram. Ask for your employer’s annual hearing conservation audiograms — they usually show exactly when the shift happened.
Sources
AMA Guides (5th ed.), the ear, nose, throat and related structures chapter, as applied by the California rating scheduleLabor Code § 5412§ 5500.5§ 4663Escobedo v. Marshalls (en banc)Almaraz/Guzman II (en banc)Cal/OSHA hearing conservation requirements. Impairment values are summarized, not reproduced; your rating depends on your own examination findings.
General information about California law, not legal advice about your case.
Impairment values described are from the AMA Guides, 5th Edition as applied under the California rating schedule; the Guides are a copyrighted medical text and figures here are summarized rather than reproduced. Your rating depends on your own examination findings.
Reviewed by Jamey Teitell, Partner & Trial Attorney · Last reviewed
Law Offices of Solov & Teitell, APC · (213) 380-9310
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