Key Takeaways
- You need a hearing conservation program once any employee’s noise exposure reaches an 8-hour time-weighted average (TWA) of 85 dBA, OSHA’s action level.
- Above 90 dBA TWA, the permissible exposure limit, you must also use feasible engineering controls or administrative controls, with hearing protection as backup.
- The OSHA noise standard, 29 CFR 1910.95, requires five program elements: noise monitoring, audiometric testing, hearing protection, employee training, and recordkeeping.
- Each exposed employee needs a baseline audiogram within 6 months and an annual hearing test after that. A standard threshold shift triggers written notice within 21 days.
- Keep noise exposure records for 2 years and audiometric records for as long as the employee works for you.
- Some hearing loss cases must go on the OSHA 300 log, in the hearing loss column.
Do You Need a Hearing Conservation Program? The 85 dBA Rule
If any employee’s noise exposure reaches an 8-hour time-weighted average of 85 decibels on the A-weighted scale (85 dBA), you need a hearing conservation program. That’s the occupational noise exposure action level in 29 CFR 1910.95, the Occupational Safety and Health Administration’s Occupational Noise Exposure Standard in 1910 Subpart G of the Occupational Safety and Health Standards. It equals a noise dose of 50%.
For plant and operations managers at Texas manufacturers, food processors, and bulk solids handlers, that threshold comes up fast. Grinders, compressors, pneumatic conveyors, bagging lines, hammer mills, and heavy equipment can all push noise levels past 85 dBA, and power tools used on maintenance jobs add to it. High noise levels also hurt communication, workplace safety, and worker productivity. The question isn’t whether noise is loud, but whether an employee’s time-weighted average reaches the action level.
The permissible exposure limit (PEL) is higher: 90 dBA as an 8-hour TWA. OSHA uses a 5 dB exchange rate, so every 5 dB increase halves the allowed time:
| Sound level (dBA, slow response) | Maximum duration per day |
|---|---|
| 90 | 8 hours |
| 95 | 4 hours |
| 100 | 2 hours |
| 105 | 1 hour |
| 110 | 30 minutes |
| 115 | 15 minutes or less |
From Table G-16 of 29 CFR 1910.95. Impulse or impact noise should not exceed a 140 dB peak sound level.
Above 90 dBA, OSHA requires feasible engineering controls (enclosures, sound barriers, mufflers, quieter equipment) or administrative controls (rotating workers out of loud areas) first, following the hierarchy of controls. Hearing protection devices, which are personal protective equipment at the bottom of the hierarchy of controls, fill the gap only when those controls can’t bring noise levels down. For comparison, the National Institute for Occupational Safety and Health (NIOSH), part of the Centers for Disease Control and Prevention, recommends a stricter 85 dBA limit with a 3 dB exchange rate.
Who the 1910.95 hearing conservation requirements cover
The hearing conservation requirements apply to general industry. Construction falls under 29 CFR 1926.52 and 1926.101, which set the same 90 dBA limit and require a “continuing, effective hearing conservation program” above it, with less detail. Under 1910.95(o), the hearing conservation paragraphs (c) through (n) don’t apply to oil and gas well drilling and servicing operations, though the 90 dBA limit still does.
How Noise Exposure Is Measured: Noise Dosimeter vs. Sound Level Meter
Noise monitoring is the first program element. You must monitor when information suggests any employee may be at or above 85 dBA, and your sampling must include all continuous, intermittent, and impulsive sound levels from 80 to 130 dB.
- Personal noise dosimetry. A noise dosimeter (also called an audio dosimeter) clips to the worker and logs the A-weighted sound level they’re exposed to over the shift. This is the best way to measure the time-weighted average for people who move around a plant.
- Sound level meter. A sound level meter takes spot readings of the A-weighted sound level at a location. It’s useful for noise surveys and area mapping, for checking a single machine, and, with octave band analysis, for designing engineering controls.
A good noise assessment usually starts with a survey of the A-weighted sound level in each area, then personal noise dosimetry on the job roles most likely to be over 85 dBA. Update the noise assessment whenever a change in production, process, equipment, or controls could put more employees over the action level or make current hearing protectors inadequate. You must notify each employee exposed at or above 85 dBA of the results, and let employees or their representatives observe the monitoring.
The Five Elements of an OSHA Hearing Conservation Program
| Program element | What 1910.95 requires |
|---|---|
| Noise monitoring | Measure exposure for anyone who may be at or above 85 dBA TWA; repeat when conditions change; notify exposed employees |
| Audiometric testing | Baseline audiogram within 6 months, annual audiograms, and STS follow-up, at no cost to employees |
| Hearing protection | Free hearing protectors for everyone at or above 85 dBA, a choice of types, and required use in some cases |
| Employee training | Training every year for everyone in the program |
| Recordkeeping | Noise exposure records (2 years) and audiometric records (duration of employment) |
Appendices A, B, C, D, and E of 1910.95 are mandatory and cover noise exposure computation, hearing protector attenuation, audiometers, test rooms, and calibration. Put all of this in a written program. Our guide to building a written safety program covers how OSHA reviews one.
Audiometric Testing: Baseline Audiogram, Annual Tests, and Standard Threshold Shift
Audiometric testing is the medical surveillance part of the hearing conservation program, and it works like other medical surveillance programs: the goal is STS detection before hearing loss becomes permanent. It must be available at no cost to every employee at or above 85 dBA.
- Baseline audiogram: within 6 months of an employee’s first exposure at or above the action level (within 1 year if you use a mobile test van, with hearing protection worn after 6 months). The baseline audiogram must follow at least 14 hours without workplace noise exposure; hearing protectors can substitute for the quiet period.
- Annual audiogram: a new hearing test at least once a year, compared with the baseline.
- Test details: pure-tone, air-conduction hearing exams at 500, 1000, 2000, 3000, 4000, and 6000 Hz, done by an audiologist, otolaryngologist, or physician, or by a technician certified by the Council for Accreditation in Occupational Hearing Conservation (CAOHC) or otherwise shown competent.
Standard threshold shift (STS)
A standard threshold shift is an average change of 10 dB or more at 2000, 3000, and 4000 Hz in either ear, compared with the baseline. Finding it early is the whole point of annual hearing testing, because noise-induced hearing loss can be stopped before it gets worse. You may correct for age using Appendix F and may retest within 30 days.
When a shift is confirmed, you must tell the employee in writing within 21 days. Unless a physician finds it isn’t work-related, you must also refit or retrain the employee on hearing protectors, require their use, and refer the employee for further evaluation if needed.
Emerging technology like tablet audiometry, along with mobile test vans, can make hearing testing easier to schedule at multiple sites. Whatever you use, it still has to meet the calibration and test-room requirements in Appendices C, D, and E.
Choosing Hearing Protection Devices and Checking Attenuation
You must provide hearing protectors at no cost to every employee exposed at or above 85 dBA, and let them choose from a variety of suitable hearing protection devices, such as foam earplugs, pre-molded plugs, and earmuffs. Hearing protection is personal protective equipment, so it’s the last line of defense after engineering controls and administrative controls.
Wearing hearing protection is mandatory for anyone above the 90 dBA limit, and for employees at 85 dBA or more who haven’t had a baseline audiogram yet or who have had a standard threshold shift.
Hearing protectors must reduce exposure to 90 dBA TWA or below, or to 85 dBA for employees with an STS. To check this, Appendix B lets you use the Noise Reduction Rating (NRR) on the package. When your noise measurements are in dBA, subtract 7 dB from the NRR before subtracting it from the noise level. The OSHA Technical Manual cautions that actual protection is usually lower than the label because most workers aren’t fit tested. Fit testing isn’t required, but it’s the most reliable way to know each worker’s hearing protectors are working.
Employee Training Requirements
Every employee in the hearing conservation program needs employee training every year. It must cover the effects of noise on hearing, the purpose of hearing protectors (including the pros, cons, and attenuation of each type, and how to select, fit, use, and care for them), and the purpose of audiometric testing and how the test works. You must also post a copy of the OSHA noise standard in the workplace and make it available to employees. Keep this training and education short and practical, in the languages your crews speak, and tie it into your other safety training initiatives. Our online safety training catalog can support the rest of your worker education and training.
Warning signs at high-noise areas aren’t required by 1910.95, but they help employees know where hearing protection is needed. The National Hearing Conservation Association is a good source for training ideas.
Records You Must Keep and for How Long
| Record | Retention |
|---|---|
| Noise exposure measurement records | 2 years |
| Audiometric test records (name, job classification, test date, examiner, last calibration date, employee’s most recent noise exposure assessment) | Duration of the employee’s employment |
| Background sound level measurements for audiometric test rooms | Maintain with your audiometric program (no separate period listed) |
These records and documents are part of workers’ rights under the standard: employees, former employees, their representatives, and OSHA can request access to them. Transfer them to a successor employer if you sell the business.
Program review or evaluation
OSHA doesn’t set a schedule, but an annual program review or evaluation is good practice. Your environmental health & safety (EHS) team should compare this year’s audiograms, noise surveys, and hearing protector choices against last year’s, and keep those records and documents with the program. A rising number of shifts means your controls or hearing protection aren’t working.
When Hearing Loss Is Recordable on the OSHA 300 Log
Under 29 CFR 1904.10, record a hearing loss case on the OSHA 300 log when both of these are true:
- The employee has a work-related standard threshold shift in one or both ears, and
- The employee’s total hearing level in that same ear is 25 dB or more above audiometric zero, averaged at 2000, 3000, and 4000 Hz.
You can age-adjust when deciding whether an STS happened, but not for the 25 dB test. If a retest within 30 days doesn’t confirm the STS, you don’t have to record it. Check the hearing loss column on the OSHA 300 log. Our guide to OSHA recordkeeping requirements covers the rest of the log.
Frequently Asked Questions
At what noise level is a hearing conservation program required?
OSHA requires a hearing conservation program when employee noise exposure reaches an 8-hour time-weighted average of 85 dBA, the action level in 29 CFR 1910.95(c). That equals a noise dose of 50%.
What is the OSHA noise exposure limit?
The permissible exposure limit is 90 dBA as an 8-hour time-weighted average, with a 5 dB exchange rate: 95 dBA for 4 hours, 100 dBA for 2 hours, and 115 dBA for 15 minutes or less. Impulse noise should not exceed a 140 dB peak sound level.
How often is audiometric testing required?
Employees need a baseline audiogram within 6 months of their first exposure at or above 85 dBA (1 year if you use a mobile test van), then an annual audiogram every year after that.
What is a standard threshold shift?
A standard threshold shift (STS) is an average hearing loss of 10 dB or more at 2000, 3000, and 4000 Hz in either ear, compared with the baseline audiogram. The employee must be told in writing within 21 days, which is why fast STS detection matters.
When is hearing loss recordable on the OSHA 300 log?
Record it when an employee has a work-related standard threshold shift and their total hearing level in the same ear is 25 dB or more above audiometric zero, averaged at 2000, 3000, and 4000 Hz.
How long must hearing conservation records be kept?
Keep noise exposure measurement records for 2 years and audiometric test records for the duration of the employee’s employment.
Does OSHA require fit testing for hearing protectors?
No. 1910.95 doesn’t require fit testing of hearing protection devices, but OSHA notes that real-world protection is usually lower than the label because most workers aren’t fit tested, so individual fit testing is a strong practice.
Where Aggie Safety Fits In
Aggie Safety helps Houston-area plants and their environmental health & safety teams build hearing conservation programs that hold up to OSHA review. Our noise conservation program services include noise surveys and personal noise dosimetry, on-site audiometric testing in a calibrated mobile booth with audiologist review, help selecting hearing protection, annual training in English and Spanish, and recordkeeping. For broader program support, see our OSHA compliance services in Houston.
Related reading: OSHA Recordkeeping Requirements for Houston Employers, How to Build a Written Safety Program That Actually Satisfies OSHA, and Crystalline Silica Exposure Limits (another exposure-monitoring standard that works the same way).
Call (713) 613-2830 or request a free consultation to find out whether your plant needs a hearing conservation program and what yours is missing.
