How Often Should Hearing Testing Be Conducted for Occupational Health Compliance?

Employers ask this question expecting a single number, once a year, and that is close to right, but the detail that trips up most programs is whose year it is. The audiogram clock does not run from January 1 or from the company's fiscal year. It runs from each employee's own baseline test date, which means a hearing conservation program with fifty employees can have fifty different due dates spread across the calendar, not one shared deadline everyone hits at once.

What does OSHA actually require?

Under 29 CFR 1910.95, employers must enroll employees in a hearing conservation program once their eight-hour time-weighted average noise exposure reaches 85 decibels, using the OSHA action level rather than the higher permissible exposure limit. Once enrolled, an employee gets a baseline audiogram within six months of that first exposure, extended to a year if a mobile test van is used, provided hearing protectors are issued in the meantime. From that baseline date forward, the standard requires an annual audiogram, not an annual calendar-year test, so the anniversary is tied to the individual, not to the company's testing season. Employers who schedule "everyone in October" are following a convenient business rhythm, not the actual regulatory clock, and can be out of compliance for employees hired at other times of year, even though every test on the calendar technically got done.

Why does the baseline date matter more than the calendar date?

The baseline audiogram is the reference point every future test gets compared against, and OSHA's annual test requirement exists specifically to catch a standard threshold shift, a documented worsening of hearing relative to that baseline, while it is still recent enough to act on. If a program tests everyone once a year on a fixed company date regardless of individual baseline dates, an employee hired eight months after the last company-wide test session goes nearly two years between their true baseline and their first annual comparison. That gap defeats the purpose of the standard, which is early detection, and it is also the kind of scheduling error that shows up clearly when an OSHA compliance officer pulls individual employee audiogram histories during an inspection rather than a company summary, since the gap is invisible at the program level and only visible one employee at a time.

What happens between annual tests?

Event	What triggers it	Timing relative to annual cycle
Baseline audiogram	Employee reaches the 85 dBA action level	Within 6 months of first exposure (12 with mobile testing)
Annual audiogram	Standard 1910.95 requirement	Every year from the employee's own baseline date
Standard threshold shift review	Comparison against baseline shows a significant shift	Triggers retest, notification, and possible retraining outside the normal cycle
Revised baseline	Persistent shift confirmed by a professional reviewer	Resets the reference point for future annual comparisons

Who reviews the results and what happens after a shift?

A licensed or certified audiologist, otolaryngologist, or physician must review audiogram results that show a standard threshold shift, and technicians performing the tests need training that meets OSHA's requirements, commonly documented through CAOHC certification. When a shift is confirmed, the employer has specific follow-up obligations: notify the employee in writing within 21 days, fit or refit hearing protectors, provide retraining, and refer for further evaluation if the shift is not attributable to a temporary threshold shift or an unrelated condition. None of this happens on the annual schedule. It happens on its own clock, triggered by the result itself, which is why a program that only tracks the once-a-year test date and not the shift-response deadlines will miss the follow-up steps even when the test itself happened on time, and why the notification deadline is the piece most often missed under deadline pressure.

How does Foster handle this?

When we run mobile hearing testing for a customer, we track each employee's actual baseline date, not just a company-wide test day, so the annual comparison is measured against the right reference point instead of whatever the last group session happened to be. Our technicians flag standard threshold shifts at the time of testing so the employer's 21-day notification clock starts immediately rather than after someone reviews results later, and our Compliance Workspace keeps each employee's next due date visible between visits instead of relying on someone remembering who was tested when.

FAQ

Does the annual audiogram have to happen on the same date every year?

It has to happen within roughly a year of the previous test, tied to the employee's own baseline or prior annual date. It does not need to fall on a fixed calendar date, and most programs build in a scheduling window rather than a single day.

What noise level triggers enrollment in a hearing conservation program?

An eight-hour time-weighted average of 85 decibels, OSHA's action level under 1910.95, which is lower than the 90 decibel permissible exposure limit that triggers engineering or administrative controls.

Who has to review a standard threshold shift?

A licensed or certified audiologist, otolaryngologist, or physician. The technician performing the test flags the result; the professional review and any required medical referral follow separately.

Can a mobile testing provider still meet the six-month baseline deadline?

Yes, OSHA extends the baseline deadline to twelve months when mobile test vans are used, as long as hearing protectors are issued and employees are instructed to wear them until the baseline test happens.

Foster provides on-site and mobile hearing testing and calibrates the audiometers these programs run on through our instrument calibration service. For more on the math behind a shift determination, see our related post on standard threshold shift calculations, or get a quote to set up baseline-accurate scheduling.

Sources

• 29 CFR 1910.95, Occupational noise exposure (OSHA)
• Council for Accreditation in Occupational Hearing Conservation (CAOHC)