100+ Free COHC Practice Questions
Pass your CAOHC Certified Occupational Hearing Conservationist exam on the first try — instant access, no signup required.
Under OSHA 1910.95, how long must an employer retain audiometric test records?
Key Facts: COHC Exam
20 hours
CAOHC Course Length
Required for initial COHC certification
85 dBA
OSHA Action Level
29 CFR 1910.95
90 dBA
OSHA PEL
29 CFR 1910.95 (8-hr TWA)
10 dB
STS Criterion
Average at 2/3/4 kHz
5 years
Recertification Cycle
CAOHC 8-hour refresher
50 questions
Written Exam Length
CAOHC certification assessment
30+ years
Audiogram Retention
Employment + 30 years (OSHA)
140 dB
Impulse Noise Peak Limit
OSHA 1910.95
The COHC exam is a 50-question written assessment administered within a 20-hour CAOHC-certified course. Topics include ear anatomy, audiometric testing, OSHA 29 CFR 1910.95 noise regulations, hearing protection devices, ototoxicity, and HCP management. No formal prerequisites; recertification is every 5 years via an 8-hour refresher.
Sample COHC Practice Questions
Try these sample questions to test your COHC exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.
1Which structure transmits sound vibrations from the tympanic membrane to the oval window?
2The cochlea is divided into three fluid-filled compartments. Which compartment contains endolymph?
3Inner hair cells are the primary sensory transducers in the cochlea. Approximately how many inner hair cells does the human cochlea contain?
4Which cranial nerve carries auditory information from the cochlea to the brainstem?
5The vestibular system detects two types of motion. Which structures detect linear acceleration and gravity?
6On an audiogram, higher frequencies are plotted to the right and greater hearing loss is plotted downward. What does the x-axis represent?
7dB A-weighting (dBA) is used for occupational noise measurements because it:
8If a sound increases by 10 dB, its intensity (energy) increases by approximately:
9What frequency range does pure-tone audiometry test during occupational audiometric monitoring under OSHA 29 CFR 1910.95?
10Under OSHA 29 CFR 1910.95, a standard threshold shift (STS) is defined as an average shift of how many dB at 2000, 3000, and 4000 Hz?
About the COHC Exam
The COHC (Certified Occupational Hearing Conservationist) credential, issued by CAOHC, qualifies technicians to conduct occupational audiometric testing and support workplace hearing conservation programs under the supervision of an audiologist or physician. Candidates must complete a 20-hour CAOHC-approved course including audiometric and HPD fitting practica, then pass a 50-question written exam and practical assessments. Recertification requires an 8-hour refresher course every 5 years.
Questions
50 scored questions
Time Limit
Within 20-hour course
Passing Score
Pass on written and practical assessments
Exam Fee
$695–$1,295 (CAOHC (Council for Accreditation in Occupational Hearing Conservation))
COHC Exam Content Outline
Ear Anatomy & Physiology
Pinna, ear canal, tympanic membrane, ossicular chain, cochlea, organ of Corti, hair cells, vestibular system, CN VIII, tonotopic organization
Hearing Physics & Audiometry
Frequency (Hz), intensity (dB SPL/HL/A), audiogram conventions, pure-tone air conduction, Hughson-Westlake technique, calibration (daily biologic/functional, annual ANSI S3.6), ANSI S3.1 booth requirements
Noise Exposure & Regulations
OSHA 1910.95 (85 dBA action level, 90 dBA PEL, 5-dB exchange rate), NIOSH REL (85 dBA, 3-dB exchange rate), TWA calculation, noise dose, continuous/intermittent/impulse noise, MSHA Part 62, 140 dB peak limit
Hearing Conservation Program
HCP five elements, noise monitoring (dosimetry/area), engineering and admin controls hierarchy, employee training (annual, OSHA content), professional review, OHC scope of practice, COHC course/recertification requirements, DOEHRS-HC
Hearing Protection Devices
NRR, EPA labeling, NIOSH derating factors, OSHA simplified method, foam/premolded/semi-insert/custom/earmuff types, double protection, fit testing (REAT), insertion technique
Ototoxicity & Chemical Hazards
Aminoglycosides, salicylates, loop diuretics, cisplatin, styrene/toluene/xylene solvents, lead, mercury — mechanisms and noise interaction
How to Pass the COHC Exam
What You Need to Know
- Passing score: Pass on written and practical assessments
- Exam length: 50 questions
- Time limit: Within 20-hour course
- Exam fee: $695–$1,295
Keys to Passing
- Complete 500+ practice questions
- Score 80%+ consistently before scheduling
- Focus on highest-weighted sections
- Use our AI tutor for tough concepts
COHC Study Tips from Top Performers
Frequently Asked Questions
What is the COHC certification?
The Certified Occupational Hearing Conservationist (COHC) is a credential issued by the Council for Accreditation in Occupational Hearing Conservation (CAOHC). It qualifies technicians to conduct occupational audiometric testing and administer hearing conservation programs under audiologist or physician supervision.
How do I become a COHC?
Complete a CAOHC-approved 20-hour certification course (no prerequisites) that includes at least 180 minutes of audiometric practicum and 60 minutes of HPD fitting practicum, then pass the 50-question written exam and practical assessments administered during the course.
What topics are on the COHC exam?
The COHC exam covers ear anatomy and physiology, hearing physics, audiometric testing procedures, OSHA 29 CFR 1910.95 noise regulations (85 dBA action level, 90 dBA PEL, 5-dB exchange rate), hearing protection device selection and NRR calculations, ototoxic chemicals, STS criteria, and hearing conservation program elements.
How often must COHC certification be renewed?
COHC certification is valid for 5 years. Recertification requires completing an 8-hour CAOHC-approved refresher course. There is no written-exam-only renewal pathway.
What is the OSHA action level for noise?
OSHA 29 CFR 1910.95 sets the action level at 85 dBA as an 8-hour TWA. At or above this level, employers must implement audiometric testing, provide hearing protection devices, and conduct annual training. The permissible exposure limit (PEL) is 90 dBA.
What is a standard threshold shift (STS)?
Under OSHA 1910.95, an STS is an average change of 10 dB or more in hearing thresholds at 2000, 3000, and 4000 Hz in either ear, compared to the baseline audiogram. Age correction per ANSI tables may be applied; confirmed work-related STS meeting the 25 dB HL criterion is recorded on the OSHA 300 log.
How is NRR derating applied?
NIOSH recommends derating the labeled NRR to estimate real-world attenuation: earmuffs × 0.75, formable (foam) earplugs × 0.50, all other earplugs × 0.30. OSHA's simplified method uses (NRR − 7) / 2 for dBA TWA calculations.