CAOHC Certification: What In-House Hearing Testers Need to Know

If you're bringing audiometric testing in-house, the first practical question is who will run the tests. For most employers the answer is an employee who completes CAOHC certification and becomes an occupational hearing conservationist. Here's what that involves and how it fits into an OSHA-compliant program.

What is CAOHC?

CAOHC is the Council for Accreditation in Occupational Hearing Conservation. It sets the standards for training occupational hearing conservationists — the technicians who perform audiometric testing and support hearing conservation programs in workplaces. CAOHC certifies Course Directors, who in turn teach the certification courses.

A technician who completes the course and certification is commonly referred to as a certified occupational hearing conservationist (COHC).

Does OSHA require CAOHC certification?

Not strictly — but it's the most common way to meet the requirement. OSHA 29 CFR 1910.95 says audiometric tests must be performed by:

• A licensed or certified audiologist, otolaryngologist, or other physician, or
• A technician who is certified by CAOHC, or who has satisfactorily demonstrated competence in administering audiometric examinations, obtaining valid audiograms, and properly using, maintaining, and checking calibration and proper functioning of the audiometers being used.

A technician — certified or not — must be responsible to an audiologist, otolaryngologist, or physician. And a technician who operates microprocessor audiometers does not need to be certified.

Because "demonstrated competence" is hard to prove after the fact, most employers choose CAOHC certification. It gives you a documented, recognized credential if an inspector or auditor asks who performed the tests.

What the CAOHC course covers

The certification course is roughly 20 hours, usually delivered over two and a half to three days, and taught by a CAOHC-certified Course Director. Content typically includes:

• Hearing and noise basics: How the ear works, how noise damages hearing, and what noise-induced hearing loss looks like on an audiogram
• OSHA (and MSHA) requirements: The elements of a hearing conservation program and the employer's obligations
• Audiometric testing: Hands-on practice with pure-tone air-conduction testing, instructing the employee, headphone placement, and recognizing unreliable responses
• Calibration and daily checks: What a functional (biological) check is and why it must be done before each day's testing
• Test environment: Why background noise matters and how Appendix D limits apply
• Hearing protection: Selection, fitting, training, and attenuation
• Records and follow-up: Baseline comparison, standard threshold shift, and when to refer to the professional supervisor

Courses end with an exam that includes both written and practical components. Specific requirements are set by CAOHC and the course provider, so confirm the details when you register.

Cost and time commitment

Course fees vary by provider and location. As an approximate range, many courses cost roughly $500–$1,000, not including travel. Some providers also run courses on-site for groups, which can make sense if you're training several testers at once. Get quotes from a few providers — the CAOHC website lists approved courses.

Plan for the employee to be away from their normal duties for the full course, plus some ramp-up time afterward to get comfortable running tests on your own equipment.

Questions to ask a course provider

• Is the Course Director currently CAOHC-certified? Only courses taught by a certified Course Director lead to CAOHC certification.
• How much hands-on time is included? Practical testing experience matters more than lecture hours for a new tester.
• What equipment is used in practice sessions? Ask whether trainees can practice on equipment similar to what they'll use on the job.
• What's included in the fee? Materials, exam, and certification processing are sometimes separate.
• Do you offer on-site group courses or recertification courses? Useful if you're training several testers or planning ahead for the five-year renewal.

How long certification lasts

CAOHC certification for occupational hearing conservationists is valid for five years. To keep it current, the technician completes a recertification (refresher) course before it expires. Put the expiration date on the same calendar you use for audiometer calibration — an expired certification is an easy finding to avoid.

Who to certify

The best candidates are usually already close to your safety or occupational health function:

• Occupational health nurses
• Safety or EHS coordinators
• HR or onboarding staff who already see every new hire — useful for getting baselines done in the first week
• Experienced shift leads on off-shift crews, so night and weekend employees can be tested without special scheduling

Certify at least two people if you can. One tester is a single point of failure: vacations, turnover, or a busy month can put your annual schedule behind.

The professional supervisor

Certification doesn't make a technician independent. OSHA requires the technician to be responsible to an audiologist, otolaryngologist, or physician, and problem audiograms must be reviewed by one of those professionals, who determines whether further evaluation is needed.

For an in-house program, that means arranging a professional supervisor before you start testing. Many employers contract with an audiologist or occupational medicine physician for this — reviewing flagged audiograms, signing determinations, and advising on referrals and baseline revisions.

What a certified tester does day to day

• Runs the functional check on the audiometer before each day's testing, and records it
• Confirms the test room meets Appendix D and nothing has changed nearby
• Tests new hires for baselines (after at least 14 hours without workplace noise exposure) and runs annual audiograms at 500, 1000, 2000, 3000, 4000, and 6000 Hz in each ear
• Schedules retests within 30 days when a standard threshold shift appears
• Refers problem audiograms to the professional supervisor
• Keeps calibration, background noise, and test records complete

For the full program setup, see how to start an in-house hearing conservation program. To see whether in-house testing makes financial sense compared with mobile vans or clinics, read our mobile van vs. in-house cost comparison.

Making the tester's job easier

A certified tester's time is best spent testing, not transcribing. AudiVault's iPad audiometer is built to ANSI S3.6-2025 audiometer specifications and sends results straight to the AudiVault cloud platform, where they're compared against the employee's baseline, checked for STS with OSHA age correction, and routed to your professional supervisor for electronic sign-off on determination letters. Every change is recorded in an audit trail, and results from other audiometers can be imported via CSV.