A hearing conservation program is the set of noise monitoring, audiometric testing, hearing protection, training and recordkeeping that OSHA requires when workers are exposed to noise at or above an 85 dBA eight-hour average.
A hearing conservation program is a structured set of practices an employer uses to prevent occupational hearing loss among workers exposed to hazardous noise. In US general industry, it is required by OSHA's occupational noise standard, 29 CFR 1910.95, whenever employee noise exposures equal or exceed an eight-hour time-weighted average of 85 decibels on the A-weighted scale (85 dBA). That threshold is called the action level.
The program has five core parts: noise monitoring, audiometric testing, hearing protection, training and recordkeeping. Together they are designed to find out who is exposed, catch early hearing changes before they become disabling, and make sure protection is actually used. A hearing conservation program does not replace efforts to reduce the noise itself. OSHA's permissible exposure limit is 90 dBA as an eight-hour average, and above that level employers must use feasible engineering or administrative controls first, with hearing protection as a supplement.
Hearing conservation matters because noise-induced hearing loss is permanent and usually painless. It builds slowly over years, and by the time a worker notices trouble following a conversation in a noisy room, the damage to the inner ear cannot be reversed.
NIOSH recommends a stricter limit of 85 dBA with a 3 dB exchange rate, under which allowable time halves with every 3 dB increase. Many employers use NIOSH criteria internally because they better reflect the energy that reaches the ear.
Employers must monitor noise to identify which employees are exposed at or above the action level. Area surveys with a sound level meter help map noisy zones, while personal noise dosimeters worn for a full shift capture what an individual actually receives as they move around. Monitoring must be repeated when changes in production, process, equipment or controls could increase exposures enough to bring more people into the program or make existing hearing protection inadequate. Employees must be notified of results that put them at or above the action level, and they have the right to observe monitoring.
Each employee in the program needs a valid baseline audiogram within six months of first exposure at or above the action level. If the employer uses a mobile test van, the deadline extends to one year, provided the employee wears hearing protection after the first six months. The baseline should be preceded by at least 14 hours without workplace noise exposure, which hearing protection can satisfy. After the baseline, audiograms are repeated at least annually.
Each annual audiogram is compared with the baseline to check for a standard threshold shift (STS), defined as an average change of 10 dB or more at 2,000, 3,000 and 4,000 Hz in either ear. OSHA allows an age correction. If an STS is found, the employee must be notified in writing within 21 days, hearing protection must be refitted or reevaluated, and the employee may need to be referred for further evaluation. A retest within 30 days can be used to confirm the result.
Employers must make hearing protectors available at no cost to all employees exposed at or above the action level and must offer a variety of suitable types, such as foam plugs, pre-molded plugs, banded plugs and earmuffs. Hearing protection is mandatory for employees exposed above the permissible exposure limit, for those with an STS, and for those who have not yet had a baseline audiogram. Protectors must reduce exposure to 90 dBA or below, or to 85 dBA for employees who have had an STS. Fit matters more than the rating on the box. A foam plug that is not inserted deep enough may give a fraction of its labeled noise reduction rating.
Employees in the program must be trained at least annually on the effects of noise on hearing, the purpose of hearing protectors along with the advantages, disadvantages and attenuation of different types, how to select, fit, use and care for them, and the purpose of audiometric testing. Training should be updated when protective equipment or work processes change.
Noise exposure measurements must be kept for two years. Audiometric test records must be kept for the duration of the affected employee's employment, and must include the employee's name, job, test date, examiner, the date of the audiometer's last calibration and the employee's most recent noise exposure assessment.
Under OSHA's recordkeeping rule at 29 CFR 1904.10, a hearing loss case must be recorded on the OSHA 300 log when an employee has an STS in one or both ears and the hearing level in the same ear is 25 dB or more above audiometric zero, averaged at 2,000, 3,000 and 4,000 Hz. Rising numbers of recordable hearing cases are a lagging indicator that a program is not working.
In construction, 29 CFR 1926.52 sets noise limits and requires a continuing, effective hearing conservation program when limits are exceeded, but it does not spell out the detailed elements found in the general industry standard. Many contractors follow the general industry model as best practice.
A corrugated packaging plant had run a hearing conservation program for years, with annual audiograms performed by a mobile van. When a new safety manager reviewed the files, she found that eleven employees had shown an STS over the previous two years, but none had been notified in writing, and no one had checked whether their hearing protection fit. Most of them worked near a new high-speed die cutter installed after the last noise survey.
The plant commissioned full-shift dosimetry, which showed exposures near the die cutter had climbed from 88 to 94 dBA. Maintenance installed an acoustic enclosure around the cutter's blower and replaced worn bearings, bringing exposures back under 90 dBA. All employees in the area received individual earplug fit testing, which showed several were getting less than half their plugs' rated attenuation. The affected employees were notified, refitted and retested, and the safety team added a monthly review of new audiogram results to its schedule so that no STS would sit unaddressed again.
Almost never. Typical office noise is well below 85 dBA. The requirement depends on measured exposure, not industry, so warehouses, print rooms, kitchens and maintenance shops attached to office buildings may still need to be assessed. If people have to raise their voices to be heard at arm's length, it is worth measuring.
Not above the permissible exposure limit. OSHA requires feasible engineering and administrative controls when exposures exceed 90 dBA, with hearing protection used in addition. Below that, hearing protection is the main control for exposures between 85 and 90 dBA, though reducing the noise at the source is always more reliable.
Individual fit testing systems measure the actual attenuation a worker gets from a protector. Without one, a quick check is that a well-inserted foam plug should make the wearer's own voice sound louder and outside noise noticeably muffled. Training on rolling, inserting and checking plugs makes a large difference.
Notify the employee in writing within 21 days, refit and retrain them on hearing protection, require its use if not already required, and refer them for clinical or otological evaluation where appropriate. Also review whether noise levels in their area have changed.
Part of SafetyIQ's EHS glossary: plain-English definitions of workplace health and safety terms.
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