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Appendix F of OSHA 1910.95 contains a provision most safety managers have never used: an age correction calculation that allows employers to subtract the expected contribution of presbycusis — age-related hearing loss — from an apparent standard threshold shift before deciding whether an STS has occurred. The calculation is based on NIOSH-developed tables, is entirely optional, and when applied correctly can prevent false-positive STS determinations for older workers. But it can only be used for one purpose, and using it incorrectly creates compliance gaps with real consequences.
Soundtrace’s Professional Supervisor applies age correction consistently and appropriately as part of every audiogram review, with the correction decision documented per worker.
A 58-year-old male worker with 10 dB of apparent threshold shift at 4000 Hz between his age-52 baseline and current audiogram may have 3–4 dB of that shift attributable to expected age-related hearing loss, not occupational noise. Without age correction, that worker appears to have an STS triggering notification, retraining, and potential 300 Log entry. With age correction, the adjusted shift may fall below the 10 dB STS threshold — no notification required, no 300 Log entry.
Presbycusis is the gradual, symmetric, high-frequency hearing loss that occurs as a normal part of aging. It is caused by degeneration of cochlear hair cells, changes in the cochlear blood supply, and neuronal loss in the auditory pathway — processes that begin in the third decade of life and accelerate after age 60. Presbycusis preferentially affects high-frequency hearing and creates a characteristic audiometric pattern of gradually increasing thresholds at 2000, 3000, 4000, and 6000 Hz.
Because presbycusis affects the same frequencies as noise-induced hearing loss, the two conditions are audiometrically difficult to distinguish. A worker who has developed 20 dB of threshold elevation at 4000 Hz over 10 years may have acquired that loss from occupational noise, from natural aging, or from a combination. Without age correction, all of it counts toward an STS determination under OSHA 1910.95(g)(10).
OSHA Appendix F provides sex-specific tables of expected age-related threshold changes at each audiometric frequency. The correction procedure involves three steps:
Step 1: Find the worker’s age at the time the baseline audiogram was taken. Look up the age correction values for each frequency (1000–6000 Hz) from the appropriate Table F-1 (males) or F-2 (females).
Step 2: Find the worker’s age at the time of the most recent (annual) audiogram. Look up the age correction values for those same frequencies from the same table.
Step 3: Subtract the baseline-age correction values from the current-age correction values. The difference represents the expected age-related threshold change over the period between the two audiograms. Subtract this from the apparent threshold shift in the annual audiogram to get the age-corrected threshold shift.
If the age-corrected average shift at 2000, 3000, and 4000 Hz is less than 10 dB, no STS has occurred under the age-corrected analysis. If it is still 10 dB or more, the STS persists even after age correction.
A male worker had his baseline audiogram at age 27. His current annual audiogram is taken at age 32. At 4000 Hz, his baseline threshold was 5 dB HL; his current threshold is 25 dB HL. The apparent threshold shift is 20 dB.
From OSHA Table F-1 (males): the age correction value at 4000 Hz is 3 dB at age 27 and 5 dB at age 32. The difference is 2 dB — the expected aging contribution over the 5-year period. Subtracting 2 dB from the apparent 20 dB shift yields an age-corrected threshold shift of 18 dB at 4000 Hz. This still exceeds the 10 dB STS threshold at this frequency, so the STS determination is unchanged in this case. But for a worker with a 12 dB apparent shift at 4000 Hz and 3 dB of expected aging contribution, the age-corrected shift drops to 9 dB — below the STS threshold.
The most important limitation of age correction is that it cannot be applied to the OSHA 300 Log 25 dB hearing threshold level test under 1904.10. The recordability test requires evaluating the worker’s actual, unadjusted total hearing level at 2000, 3000, and 4000 Hz against the 25 dB above audiometric zero threshold. Age correction is expressly prohibited here by 1904.10(b)(2)(ii).
Employers and some third-party HCP vendors mistakenly apply age correction to the 300 Log recordability determination as well as the STS determination. This is a recordkeeping violation. An employer who uses age correction to conclude that a 300 Log entry is not required — when the worker’s unadjusted hearing level exceeds 25 dB above audiometric zero — has failed to make a required recordkeeping entry. The correction applies only to the STS test under 1910.95, not to the recordability test under 1904.10.
OSHA does not require employers to apply age correction. It is entirely optional. But whatever decision an employer makes — to apply it or not apply it — must be applied consistently across the entire program. An employer who applies age correction for some workers but not others, or who applies it when it helps but not when it makes no difference, creates a compliance record that may be challenged during an inspection or litigation.
Best practice is to establish a written policy at the program level, document whether age correction is applied in each audiometric review, and have the Professional Supervisor confirm the application consistently. The decision is typically made during audiometric database setup and should be part of the written HCP documentation.
Soundtrace’s audiometric review applies Appendix F age correction consistently across all enrolled workers, with the correction decision documented per record — ensuring compliance and defensibility for both STS determinations and 300 Log entries.
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