Audiometric Testing Services: What They Cover and Who Needs Them

Audiometric testing services measure an employee's hearing against a baseline so an employer can catch noise-induced hearing loss before it becomes permanent. Under 29 CFR 1910.95, any employee with an 8-hour time-weighted average noise exposure at or above 85 decibels has to be enrolled in a hearing conservation program, which includes a baseline test, annual retests, and a review of any shift in hearing ability. Foster provides mobile hearing testing that brings this service to the worksite instead of a clinic.

What does an audiometric test actually measure?

Pure-tone audiometry presents tones at set frequencies and volumes through headphones or insert earphones and records the quietest level the employee can hear at each frequency, usually 500 Hz through 6000 Hz. The result is an audiogram: a graph of hearing threshold by frequency for each ear. A baseline audiogram, taken within six months of an employee's first exposure (one year if a mobile van is used and hearing protectors are worn in the meantime), becomes the reference point every later test is compared against. Annual retests are then measured against that baseline, not against the prior year's test, so a slow multi-year decline doesn't get missed one comparison at a time.

Does the test have to happen in a soundproof booth?

No. OSHA's standard sets maximum permissible ambient noise levels for the octave bands used in testing, listed in Appendix D to 1910.95, rather than mandating a sound-isolating booth. A mobile testing vehicle or a quiet room that meets those background-noise limits is compliant. What matters is that the vendor or in-house technician actually measures ambient noise at the test location and documents that it falls under the Appendix D limits; a booth is simply one way to guarantee that, not a requirement in itself.

Who is qualified to administer the test?

1910.95(g)(3) allows the test to be given by a technician certified by the Council for Accreditation in Occupational Hearing Conservation (CAOHC), or by someone who has demonstrated competence in administering audiometric exams and is supervised by an audiologist, otolaryngologist, or physician. The CAOHC credential (an Occupational Hearing Conservationist, or OHC, certification) is renewed every five years. Audiogram review, meaning the judgment call on whether a shift is a standard threshold shift (STS) requiring employer action, must be done by a licensed or certified audiologist, otolaryngologist, or physician, or under their supervision by a CAOHC-certified technician using their defined criteria.

What is a standard threshold shift, and what happens after one?

A standard threshold shift is a change in hearing threshold relative to the baseline audiogram, averaged over 2000, 3000, and 4000 Hz, of 10 dB or more in either ear. When a retest shows an STS, 1910.95(g)(8) requires the employer to notify the employee in writing within 21 days, and the reviewing professional decides whether the shift is work-related and whether the employee needs referral for further evaluation. An age correction can be applied to the comparison per Appendix F before confirming the STS, which sometimes reclassifies what looked like a shift as expected age-related change instead. A confirmed, work-related STS is also an OSHA 300 Log recordable event under 1904.10.

Test stage	Timing	Compared against
Baseline audiogram	Within 6 months of first exposure (12 months if using mobile testing with interim hearing protection)	No prior test; this becomes the reference
Annual retest	Every 12 months while enrolled	The baseline audiogram, with optional age correction
Revised baseline	After a confirmed, persistent STS, at the professional's discretion	Replaces the original baseline going forward

What should a compliant audiometric test report include?

A usable report states the test date, the technician's credential, the audiometer's calibration status, and the frequency-by-frequency results for both ears, alongside an explicit flag for any STS or OSHA-recordable finding rather than raw numbers alone. Records themselves must be kept for the duration of employment plus 30 years under 1910.95(m) and 1910.1020. A report that buries an STS inside a column of numbers, with no flag and no notification trigger, puts the employer at risk of missing the 21-day written notice requirement even though the data was technically delivered on time.

How Foster handles this

Foster's audiometric testing is performed by CAOHC-certified or demonstrated-competence technicians, on audiometers carrying current calibration certificates, with ambient noise verified against Appendix D at every test location whether it's a dedicated booth or a mobile setup. Reports flag STS and recordable findings explicitly rather than leaving the employer to do that math. For employers also tracking respirator fit testing and BAT training renewal dates against separate OSHA and DOT clocks, Foster's compliance workspace keeps every employee's due dates in one place instead of three separate spreadsheets.

Related reading: see our breakdown of what an OSHA hearing conservation citation actually costs and our guide to STS follow-up actions for what happens after a shift is confirmed. Foster also offers instrument calibration and on-site occupational health testing; request a quote for your site.

FAQ

Is a baseline audiogram required before an employee starts noisy work?

The baseline must be completed within 6 months of the employee's first exposure at or above the 85 dBA action level, or within 12 months if mobile testing is used and the employee wears hearing protection in the interim.

Who can legally review an audiogram for a standard threshold shift?

A licensed or certified audiologist, otolaryngologist, or physician, or a CAOHC-certified technician applying that professional's defined review criteria under their supervision.

Does a standard threshold shift automatically go on the OSHA 300 Log?

Only once the shift is confirmed as a 10 dB or greater average change at 2000, 3000, and 4000 Hz relative to baseline, found work-related by the reviewing professional, and (after any permitted age correction) still meets the threshold. At that point it is OSHA-recordable under 1904.10.

How long do audiometric test records need to be kept?

For the duration of the employee's employment plus 30 years, under 29 CFR 1910.95(m) and the medical/exposure recordkeeping requirements in 1910.1020.

Sources

• 29 CFR 1910.95 - Occupational noise exposure (OSHA)
• OSHA standard interpretation, February 3, 1984 - baseline audiograms and mobile testing
• CAOHC - Occupational Hearing Conservationist FAQ