Audiometric Testing Under 1910.95: Baselines, Annual Tests, and Threshold Shift

Audiometric testing is the part of a hearing conservation program that runs on a clock. A baseline audiogram is due within six months of a worker's first exposure at or above the action level; annual tests follow; and each annual result is compared back against that baseline to see whether the worker's hearing has moved. When it has moved far enough, the standard calls that a standard threshold shift and a series of obligations fire — notification, protector re-evaluation, sometimes a recordable entry on the 300 log.

This post covers that machinery: baseline timing, what a valid test requires, how a shift is calculated and age-corrected, and what you owe the worker once one is confirmed. It assumes you already know you are over the threshold. If you are still working out whether you are, the 85 dBA action level and the 90 dBA PEL covers the exposure side.

Where the Threshold Sits and Why It Matters

Testing obligations attach at the 85 dBA 8-hour time-weighted average action level — that is the trigger that puts a worker into the audiometric program, and it is separate from the 90 dBA permissible exposure limit that governs controls. The thresholds and what each one triggers covers that distinction in full. For testing purposes, the practical question is narrower: which specific employees crossed 85, and on what date, because that date starts the six-month baseline clock.

Eighty-five decibels might sound abstract until you put it in context. A pneumatic nail gun operates around 100 dBA. A metal stamping press can easily reach 95–105 dBA. An industrial vacuum system typically runs between 85 and 90 dBA. A table saw in a carpentry shop sits around 93 dBA. These are not extreme environments. They're the routine daily backdrop of thousands of small businesses, and in each one, workers are accumulating noise dose that the standard is designed to control.

The first step is noise monitoring, and this is where many small employers stall. The rule requires monitoring whenever there's a reason to believe employees are exposed at or above the action level. That doesn't mean guessing. It means using a sound level meter or personal noise dosimeter to take actual measurements during representative work tasks. OSHA requires that affected employees or their representatives be given an opportunity to observe monitoring, and they must be notified of the results. Results also inform who needs to be enrolled in the audiometric testing program. If noise levels change — new equipment, reconfigured production lines, shift changes — monitoring must be repeated.

What a Compliant Audiometric Testing Program Looks Like

Audiometric testing is the centerpiece of the hearing conservation standard, and it's the part that most trips up small employers who think providing earplugs is enough. Under 1910.95(g), employers must establish and maintain an audiometric testing program for all employees whose noise exposures equal or exceed the 85 dBA action level.

Testing must be provided at no cost to employees. It begins with a baseline audiogram — ideally taken before an employee starts work in noisy areas, or within six months of first exposure. After that, annual audiograms are required for as long as the employee remains in the hearing conservation program. A licensed or certified audiologist, otolaryngologist, or other qualified professional must supervise the program. For the baseline audiogram to be valid, the employee must have 14 hours of quiet before the test — meaning no occupational noise exposure and, ideally, no recreational noise either. Employers are required to notify employees of this requirement.

The annual audiogram is then compared against the baseline to check for a standard threshold shift — a change of an average of 10 dB or more at 2000, 3000, and 4000 Hz in either ear. When a standard threshold shift is identified, the employer must notify the employee in writing within 21 days, fit or refit them with hearing protectors, require them to use hearing protection, and refer them to an audiologist if the shift is not age-adjusted away. A revised baseline must eventually be established if the shift persists. All audiograms must be retained for the duration of employment plus 30 years.

Hearing Protectors Are Not a Last Resort

The standard treats hearing protection as one layer of a program, not a standalone solution. Under 1910.95(i), employers must make a variety of hearing protectors available at no cost to employees exposed at or above the action level. The emphasis on variety matters. Earplugs that fit well for one worker may be useless for another due to ear canal size, facial structure, or the nature of the work. Offering a choice — foam plugs, pre-molded plugs, banded plugs, earmuffs — is both a compliance requirement and a practical step toward actual noise reduction.

Critically, the hearing protectors selected must have a noise reduction rating (NRR) adequate for the actual noise levels measured in the workplace. OSHA's guidance on attenuation requires that protectors reduce exposure below the 90 dBA PEL, and below 85 dBA for employees with standard threshold shifts or who have not yet had a baseline audiogram. Handing workers a generic foam earplug and calling it done doesn't hold up under inspection if the NRR isn't sufficient for the measured noise levels.

Supervisors carry real accountability here. A program that includes hearing protection in the written plan but doesn't enforce its use on the floor is a program that exists on paper only. OSHA inspectors regularly interview workers to understand whether they actually wear the protectors provided and whether supervisors correct them when they don't.

Training and Recordkeeping Are Non-Negotiable

Annual training is required for every employee in the hearing conservation program. The content isn't optional: the rule at 1910.95(k) specifies that training must cover the effects of noise on hearing, the purpose of audiometric testing, the purpose and use of hearing protectors, and the attenuation offered by each type of protector available in your workplace. A brief all-hands meeting that checks a box won't demonstrate compliance if workers can't explain what they were taught.

Recordkeeping requirements are specific as well. Noise monitoring measurements must be kept for two years. Audiometric test records must be retained for the duration of employment plus 30 years — a long retention window that reflects the long latency of hearing loss as a health outcome. Records must be made available to employees and their designated representatives upon request.

Building the Program Without Overcomplicating It

For small business owners who haven't yet established a formal hearing conservation program, the path forward is more manageable than it appears. Start with noise monitoring — rent or borrow a sound level meter, document the results, and identify who needs to be enrolled. Find an occupational health clinic or mobile audiometric testing provider in your area; many serve small employers on a per-employee basis, which keeps costs predictable. Select hearing protectors with adequate NRR for your noise levels and make them freely available at every entry point to noisy areas. Schedule annual training as a fixed item on your safety calendar rather than something addressed when it comes up.

The standard is detailed, but none of it is technically complex. What it requires is sustained attention over time — the kind of attention that prevents a worker from arriving at retirement age unable to hear their grandchildren. That's the point. And for employers who haven't yet built the program, starting now is still better than starting after an inspection, a citation, and a workforce that's been accumulating damage for years without any protection.