OSHA noise standard requirements for small manufacturing

Last updated 2026-07-10

What is OSHA's noise standard and which employers does it cover?

OSHA's occupational noise exposure standard lives at 29 CFR 1910.95 ^[1]. It covers general industry, which means nearly every small manufacturing shop: metal fabrication, woodworking, plastics, food processing, printing. If you run construction instead, the parallel rule is 29 CFR 1926.52, and the exposure limits are almost identical.

The standard applies to you the moment a worker's noise exposure hits an 8-hour time-weighted average (TWA) of 85 decibels (dBA). That threshold is the Action Level. Cross it and the full hearing conservation program requirements kick in. There's a second threshold, the Permissible Exposure Limit (PEL), set at 90 dBA TWA. At or above the PEL you also have to put feasible engineering and administrative controls in place, more than hand out earplugs.

Small manufacturers often assume they're too small to matter. OSHA disagrees. The standard has no employee-count exemption. A shop with four machinists running CNC lathes all day carries the same obligation as a plant with 400 workers if the noise exposure is the same.

Here's a useful frame. The standard uses a 5-dB exchange rate: every 5 dB jump in noise level cuts the allowable exposure time in half. So 90 dBA is allowed for 8 hours, 95 dBA for 4 hours, 100 dBA for 2 hours, on down to 115 dBA for 15 minutes flat ^[1]. If a worker moves through several noise sources during a shift, OSHA adds up the combined dose. The loudest single moment isn't the whole story.

What noise levels actually trigger OSHA requirements?

Two numbers do all the work: 85 dBA and 90 dBA. Memorize both.

85 dBA TWA is the Action Level. It triggers mandatory noise monitoring, audiometric testing, hearing protector availability, and annual training. Think of it as the "you have to have a program" line.

90 dBA TWA is the PEL. It triggers everything above plus a requirement to put feasible engineering controls (enclosures, damping, isolation) and administrative controls (job rotation, scheduling) in place before you lean on hearing protectors as the main fix.

To put 85 dBA in context: a typical shop floor with several machines running often sits at 85 to 95 dBA. A single angle grinder can hit 100 dBA ^[2]. Woodworking planers and jointers frequently reach 95 to 100 dBA. Pneumatic tools and metal stamping presses regularly clear 100 dBA. You don't need equipment to guess you have a problem. You need it to prove what the actual exposure is.

There's also a hard ceiling. OSHA sets a maximum of 115 dBA for any continuous noise and 140 dB peak for impulse or impact noise (think nail guns or presses). Go past those and no hearing protector makes the situation legal.

Noise Level (dBA)	Max Permissible Duration per Day
90	8 hours
92	6 hours
95	4 hours
97	3 hours
100	2 hours
102	1.5 hours
105	1 hour
110	0.5 hour
115	0.25 hour (maximum)

Source: 29 CFR 1910.95, Table G-16 ^[1]

How do you measure noise exposure in a small shop?

You have two tools: a sound level meter (SLM) and a personal noise dosimeter. A sound level meter gives you a spot reading at one location. A dosimeter clips to a worker's collar and logs their real exposure across the whole shift. For compliance, the dosimeter wins every time. It captures movement, machinery cycling on and off, and actual work patterns instead of one frozen snapshot.

OSHA requires monitoring when there's reason to believe exposure may reach the 85 dBA Action Level ^[1]. "Reason to believe" is a low bar. If workers routinely raise their voices to be heard by someone three feet away, you almost certainly have an exposure at or above 85 dBA. That's a field rule of thumb, not a legal standard, but it's a solid trigger for formal monitoring.

For the monitoring itself, you can hire an industrial hygienist (IH). That runs roughly $500 to $1,500 for a single-day assessment at a small facility, though fees vary a lot by region (I've seen quotes from $400 to $2,500). Or you rent or buy dosimeters and do it yourself after some basic training. A calibrated dosimeter rents for about $50 to $150 per day. Buying one runs $300 to $1,200 depending on features.

Whatever you measure, you have to tell affected workers the results, and they have the right to watch the monitoring happen ^[1]. That's not optional. Keep the monitoring records for at least two years.

One practical tip: monitor your worst-case shift. If Tuesday afternoon is when the punch press, the compressor, and the grinder all run at once, measure then. A quiet Tuesday morning gives you a number that doesn't reflect real conditions and won't hold up if OSHA shows up.

What does a compliant hearing conservation program actually include?

When worker exposure reaches 85 dBA TWA, 29 CFR 1910.95(c) requires a continuing, effective hearing conservation program ^[1]. "Continuing" means it's not a one-and-done. It runs as long as the exposure exists. Here's what the program has to include.

Noise monitoring. Covered above. Repeat it when production changes, new equipment arrives, or worker complaints suggest things got louder.

Audiometric testing. You must provide baseline audiograms within 6 months of an employee's first exposure at or above the Action Level, or within 1 year if you use a mobile test van ^[1]. After that, annual audiograms are required. Testing has to be free to employees, done during or after work hours, and conducted by a licensed or certified audiologist, an otolaryngologist, another qualified physician, or a technician certified by the Council for Accreditation in Occupational Hearing Conservation (CAOHC) ^[1].

Audiogram review. A qualified professional compares each audiogram to the baseline. If a worker shows a Standard Threshold Shift (STS), meaning a 10 dB or greater average shift in hearing at 2,000, 3,000, and 4,000 Hz in either ear, you must notify the worker in writing within 21 days, refit or retrain them on hearing protectors, and refer them for further evaluation if needed ^[1]. An STS can also trigger OSHA recordkeeping on the 300 log (more on that below).

Hearing protectors. You have to make a variety of protectors available at no cost. Workers must wear them when they're at or above the Action Level and their baseline audiogram hasn't been established yet, or after they've shown an STS. At or above the PEL (90 dBA), everyone in the exposed area wears protection.

Hearing protectors carry a Noise Reduction Rating (NRR). OSHA requires you to verify that the chosen protector, properly fitted, cuts exposure to at least 90 dBA (or 85 dBA for workers who've shown an STS) ^[9]. Here's the catch: the labeled NRR is a lab number. Field attenuation is typically about half that. An earplug rated NRR 30 probably delivers 15 dB in the real world. Factor that in when you pick protectors.

Training. Annual training is required for every worker at or above the Action Level. It has to cover the effects of noise on hearing, the purpose and use of hearing protectors, the pros and cons of different protector types, and the purpose and procedures of audiometric testing ^[1]. Training doesn't have to be elaborate. A 30-minute session with a handout and a sign-in sheet satisfies the rule as long as you hit those four topics.

Recordkeeping. Noise exposure records for at least 2 years. Audiometric test records for the duration of employment plus 30 years ^[1]. Yes, 30 years after employment ends. Noise-induced hearing loss takes decades to show up and can trigger workers' comp claims long after someone leaves.

Does OSHA require engineering controls or can you just use earplugs?

This is where a lot of small manufacturers get it wrong. The standard is blunt: when exposures top the PEL of 90 dBA TWA, you must put feasible engineering and administrative controls in place first ^[1]. Hearing protection is the last line of defense, not the first.

Engineering controls cut noise at the source or along the path before it reaches the worker. Mount machinery on vibration-dampening pads. Enclose loud equipment in acoustic barriers. Install mufflers on pneumatic exhaust ports. Add sound-absorbing panels to walls. Swap impact processes for hydraulic or mechanical equivalents where you can. Keep equipment maintained, because worn bearings and loose parts add noise you don't need.

"Feasible" is the word that matters. OSHA won't expect you to spend $50,000 dampening a machine worth $10,000. The agency looks at whether controls are technically and economically achievable given your size and resources. But you don't get to skip the analysis. You need to document that you evaluated engineering controls and explain why each option was or wasn't feasible.

Administrative controls cut exposure by limiting how long workers spend in noisy areas. Job rotation is the classic move: spread four hours of press operation across two workers instead of dumping it all on one person. Scheduling noisy jobs for times when fewer people are around is another.

Below the PEL (between 85 and 90 dBA), engineering controls are strongly recommended but not explicitly required by the standard. At those levels, a proper hearing conservation program with protectors and audiometric testing meets your legal obligation. Still, engineering the noise out is the better long-term answer, for productivity, communication, worker stress, and liability.

How does OSHA's noise standard affect injury recordkeeping on the OSHA 300 log?

Noise-induced hearing loss is a recordable illness under 29 CFR 1904. You record it on the OSHA 300 log when two things are both true: the case is work-related, and the employee's overall hearing level is 25 dB HL or more averaged across 2,000, 3,000, and 4,000 Hz in the affected ear ^[3].

A Standard Threshold Shift alone doesn't automatically put a case on the 300 log. The worker also needs that overall hearing level of 25 dB HL or more. You can retest within 30 days of the STS under optimal conditions (quiet room, same protocol), and if the retest doesn't confirm the shift, you don't record it ^[3].

When a hearing loss case is recordable, check column M(5) on the 300 form ("hearing loss") rather than the injury columns. OSHA's recordkeeping rule for hearing loss lives at 29 CFR 1904.10 ^[3].

For an overview of incident documentation generally, see our guide on incident reports.

Keep these two record sets straight. The 300 log is separate from audiometric records, and both exist at the same time. Your audiometric records are medical records and stay confidential under OSHA's access standard, 29 CFR 1910.1020 ^[10]. The 300 log is a workplace record that employees, former employees, and OSHA inspectors can see.

What are the OSHA penalties for noise standard violations?

OSHA adjusts its civil penalty caps every year for inflation. As of January 2024, the maximum penalty for a serious violation is $16,131 per violation, and for a willful or repeated violation it's $161,323 per violation ^[4]. That gap is the whole ballgame for noise cases.

Noise citations come in a few flavors. Failing to monitor is common. Failing to provide audiometric testing is another. The most expensive citations tend to hit employers who knew about exposures above the PEL, did nothing about engineering controls, and left workers unprotected for long stretches. Those earn willful tags.

Manufacturing is squarely in OSHA's sights. The Bureau of Labor Statistics reports that hearing loss stays among the most common occupational illnesses in manufacturing ^[5]. OSHA's Site-Specific Targeting Program and National Emphasis Programs have long focused on high-noise industries: foundries, lumber mills, metal fabrication shops.

Small businesses can earn penalty reductions. OSHA offers up to a 60% reduction for small employers, and good faith efforts to comply can knock off more ^[4]. But you have to prove the effort with documentation: noise surveys, audiogram records, training logs, a written program.

Here's the honest math. A full hearing conservation program for a 20-person shop might cost $3,000 to $8,000 a year once you count audiograms ($25 to $60 per worker from mobile testing services), hearing protectors, and training time. A single willful citation is $161,323. The program pays for itself the first time an inspector walks in.

What should a written hearing conservation program include?

29 CFR 1910.95 doesn't spell out a written program the way some other standards do. But OSHA's plain expectation (and any competent compliance attorney will tell you the same) is that you document your program on paper. If you can't hand an inspector a document, you effectively don't have a program.

A written hearing conservation program for a small manufacturer should cover, at minimum:

1. Scope: which work areas and job titles are included based on monitoring results. 2. Monitoring protocol: how often you measure, who does it, what equipment you use, and how you notify workers of results. 3. Audiometric testing: the schedule, the testing provider, how you handle STS findings, and the notification process. 4. Hearing protector selection: which types are available, where workers get them, who checks fit, and how you verify adequate attenuation. 5. Training: who delivers it, what topics it covers, when it happens (annually), and how you document attendance. 6. Recordkeeping: where records are stored, who controls access, and the retention schedule (2 years for monitoring, employment plus 30 years for audiograms). 7. Program evaluation: a stated commitment to review the program when conditions change.

If building that from scratch sounds like a slog, a safety program generator can structure it correctly fast. SafetyFolio's program tool walks you through the required elements for 1910.95 specifically, so you're not staring at a blank page.

For how written programs fit into OSHA compliance generally, we have a broader overview worth reading before you start.

How does OSHA's noise standard interact with state plan states?

Twenty-two states and two territories run their own OSHA-approved occupational safety and health programs, called State Plan states ^[6]. In those places, the state agency, not federal OSHA, enforces workplace safety rules.

Here's the point that matters. State Plan states must have standards "at least as effective as" the federal standard. They can be stricter, never weaker ^[6]. California's Division of Occupational Safety and Health (Cal/OSHA), for example, runs its own noise standard (Title 8, Section 5096) that mirrors federal 1910.95 in most respects but has procedural differences in how audiograms are handled and who qualifies as a professional reviewer.

If you're in a State Plan state, verify your state's version of the noise standard. The federal 1910.95 framework is the right mental model, but your actual obligation is to the state rule. OSHA's website lists every State Plan state and links to their programs ^[6].

For a map and a fuller explanation of how state plans work, see our OSHA training resource, which covers jurisdiction differences.

One practical note: if you run facilities in more than one state, you may face slightly different documentation requirements at each location. Build that into a single company-wide written program from the start.

What are the most common OSHA noise citation mistakes small manufacturers make?

After reviewing OSHA inspection data and enforcement patterns, a handful of failures keep showing up.

No monitoring on record. The most common gap by far. Employers assume their shop isn't loud enough, or they tested informally once with a borrowed phone app (which OSHA doesn't accept for compliance) and never documented anything formal.

Audiometric testing gaps. Missing baseline audiograms for new hires, letting annual audiograms slide a few months, or using a testing provider whose technicians aren't CAOHC-certified ^[12]. All three are citable.

Weak hearing protector variety. Tossing a box of foam earplugs in the break room doesn't meet the requirement to make a "variety" of protectors available ^[1]. Workers have different ear canal sizes. Some can't use foam inserts because of skin conditions or ear anatomy. Some need protectors that work alongside hard hats or face shields. You need at least two or three types on hand.

Training that misses the required topics. A general safety meeting that mentions "wear your ear protection" is not audiometric training. The standard names four content areas. If your training records don't reflect them, you're citable.

No STS follow-up. Spotting a Standard Threshold Shift and then doing nothing. The standard requires written notice to the employee within 21 days, refitting or retraining on protection, and referral for evaluation if indicated.

Treating earplugs as the only control above 90 dBA. Skipping the engineering controls analysis entirely. Inspectors will ask whether you evaluated and documented feasibility, and "we gave everyone earplugs" isn't the answer they want.

For how OSHA citations work across other safety topics, the lockout tagout enforcement pattern looks the same: paperwork gaps and missing training are the hooks inspectors reach for first.

How much does a hearing conservation program cost a small manufacturer?

Real numbers matter here, even if they move around. Here's a rough breakdown for a 20-person shop where 15 workers are exposed at or above the Action Level.

Noise monitoring (initial): $500 to $1,500 for an industrial hygienist, or $150 to $500 DIY with a rented dosimeter. Repeat when conditions change.

Baseline audiograms: Mobile testing companies charge roughly $25 to $60 per worker, so $375 to $900 for 15 workers. Clinic-based testing runs higher, often $80 to $150 per worker.

Annual audiograms: Same cost as baseline, every year.

Hearing protectors: Foam earplugs in bulk run $0.10 to $0.50 each. Reusable earplugs $1 to $5 each. Earmuffs $8 to $40 each. Budget $5 to $15 per worker per year for disposables plus $20 to $40 per worker for reusable options.

Training: In-house with a prepared presentation, your main cost is staff time (30 to 60 minutes, 15 workers). Third-party sessions run $200 to $800 for a group.

Written program development: A one-time cost. A consultant to write it: $500 to $2,000. A structured template or program generator: much less.

Total recurring cost for a 15-worker exposed population lands around $1,500 to $4,000 a year after setup. That's a normal cost of doing business, and it's a sliver of what a single OSHA citation or workers' comp hearing loss claim runs. NIOSH's criteria document on occupational noise puts hearing loss among the costliest chronic occupational conditions, and severe bilateral claims can reach six figures ^[2].

For building a broader safety framework, hazard communication is often the next written program small manufacturers tackle after noise.

Does OSHA's noise standard apply to part-time or temporary workers?

Yes. The standard protects workers, not job classifications. If a temporary or part-time employee is exposed at or above the Action Level on your worksite, you have obligations toward them.

For temp workers placed by a staffing agency, the question of who provides audiograms and training gets messy. OSHA's general position, stated in multiple letters of interpretation, is that the host employer controls the worksite conditions and is responsible for site-specific hazard controls, including hearing protector availability and noise monitoring ^[7]. The staffing agency is usually responsible for training that doesn't require site-specific knowledge. A written agreement between the two should spell out who does what.

For part-timers working shorter shifts, remember the 85 dBA threshold is an 8-hour TWA. A worker present only 4 hours a day in a 90 dBA environment might land below the Action Level. Run the math instead of assuming they're automatically covered or automatically exempt. Use the dose formula in Appendix A ^[8].

Contractors trip up a lot of small manufacturers. Contractors are generally their own employer and run their own hearing conservation program. But if the noise source is your equipment or your facility, and you control the exposure conditions, OSHA can hold you to a multi-employer citation standard ^[7]. Document the noise levels in contractor work areas and tell the contractor what they are.

Frequently asked questions

At what decibel level does OSHA require hearing protection?

OSHA requires you to make hearing protection available to workers exposed at or above 85 dBA TWA (the Action Level under 29 CFR 1910.95). Workers must actually wear it when they're above the 90 dBA PEL, when they're between 85 and 90 dBA and their baseline audiogram isn't established yet, or after they've shown a Standard Threshold Shift.

How often does OSHA require noise monitoring?

There's no fixed interval for repeat monitoring. 29 CFR 1910.95 requires monitoring whenever there's an indication that exposure may have climbed to a level at or above the Action Level. That covers new equipment, changed production processes, or worker complaints. Most compliance professionals re-monitor after any significant operational change. Initial monitoring must happen when exposures may reach 85 dBA TWA.

How long do you have to keep audiometric testing records?

OSHA requires audiometric test records to be kept for the duration of the affected employee's employment plus 30 years, per 29 CFR 1910.95(m). Noise exposure measurement records have a shorter retention period of 2 years. The gap exists because noise-induced hearing loss develops slowly and claims can surface decades after exposure ends.

What is a Standard Threshold Shift and what do I have to do when one occurs?

A Standard Threshold Shift (STS) is a change in hearing threshold averaging 10 dB or more at 2,000, 3,000, and 4,000 Hz in either ear compared to the baseline audiogram. When you identify one, you must notify the worker in writing within 21 days, refit or retrain them on hearing protection, and refer them for evaluation if the STS isn't work-related or further medical review is indicated. An STS may also be recordable on the OSHA 300 log.

Can a phone app replace a calibrated sound level meter for OSHA compliance?

No. OSHA requires noise monitoring instruments to meet ANSI S1.4 specifications for Type 2 sound level meters at minimum, and personal dosimeters must meet ANSI S1.25. NIOSH has evaluated smartphone sound apps and found they aren't validated to those standards, so they won't satisfy an inspector. Use a calibrated, ANSI-compliant instrument, rented or bought, or hire a professional who brings one ^[11].

Does the noise standard apply to office workers in a manufacturing building?

Only if their actual exposure reaches the 85 dBA Action Level. Office workers in a separate, acoustically isolated room with exposures below 85 dBA TWA aren't covered. If the office sits next to the shop floor with no sound isolation and workers spend real time near machinery, measure their actual TWA to know for sure. Proximity alone doesn't determine coverage. Measured exposure does.

What types of hearing protection does OSHA require me to offer?

OSHA requires a "variety" of suitable hearing protectors at no cost to employees. In practice that means at least two or three types: usually foam earplugs, pre-molded reusable earplugs, and earmuffs. The selection has to accommodate workers with different needs, including compatibility with other required PPE. You must also confirm the protectors bring exposure below 90 dBA (or 85 dBA for workers with confirmed STS).

Are OSHA noise citations common for small manufacturers?

Yes. OSHA enforcement data consistently shows noise and hearing conservation violations among the top citations in manufacturing. BLS data puts hearing loss among the most common occupational illnesses in the sector. Small shops get cited often because they lack dedicated safety staff and frequently don't realize the monitoring and audiogram requirements apply to them at all. The most common citation is simply no monitoring record.

What's the difference between the Action Level and the Permissible Exposure Limit for noise?

The Action Level (85 dBA TWA) triggers the hearing conservation program: monitoring, audiograms, hearing protector availability, and training. The Permissible Exposure Limit (90 dBA TWA) triggers additional duties: you must put feasible engineering and administrative controls in place, more than rely on protectors. Between 85 and 90 dBA, hearing protection is required in some situations but engineering controls aren't legally mandated.

Can I use job rotation to comply with the noise standard instead of engineering controls?

Job rotation is an administrative control and counts toward reducing time-weighted average exposure. It can hold workers below the Action Level or PEL by limiting individual exposure time. But above the PEL, OSHA expects you to document why engineering controls weren't feasible before relying mainly on administrative controls. Rotation lowers each person's dose. It doesn't lower the noise level for anyone in the area.

Does OSHA's noise standard require a written program?

29 CFR 1910.95 doesn't use the phrase "written program" as explicitly as some standards do, but it requires an ongoing, documented hearing conservation program. In practice, inspectors expect written documentation of your monitoring protocol, audiometric testing schedule, hearing protector selection rationale, training records, and STS follow-up procedures. Without documentation, you effectively can't prove the program exists.

What happens if a worker refuses to wear hearing protection?

You're still responsible for their exposure. OSHA holds employers accountable for providing protection, making sure it's worn, and enforcing use. If a worker refuses, you need a documented progressive discipline process showing you required and enforced use. Documenting the refusal helps, but it doesn't erase your citation risk. Some employers have workers sign an acknowledgment that they were trained and provided protection, though that isn't a legal shield.

How do I calculate noise dose when workers move between areas with different noise levels?

Use OSHA's dose formula from 29 CFR 1910.95 Appendix A: D = (C1/T1) + (C2/T2) + ..., where C is actual time in each area and T is the maximum allowable time at that noise level. If the fractions sum to 1.0 (100% dose) or more, the worker is at or above the PEL. If they sum to 0.5 (50% dose) or more, the worker is at or above the Action Level. A dosimeter runs this math for you.

Sources

1. OSHA, 29 CFR 1910.95 Occupational Noise Exposure (full standard text): Action Level is 85 dBA TWA; PEL is 90 dBA TWA; 5-dB exchange rate; audiogram retention 30 years after employment; training must cover four specified topics; variety of hearing protectors required at no cost
2. NIOSH, Occupational Noise Exposure Revised Criteria 1998: Angle grinders and similar tools can reach 100 dBA; occupational hearing loss is among the costliest chronic occupational conditions and severe bilateral claims can reach six figures
3. OSHA, 29 CFR 1904.10 Recording Criteria for Cases Involving Occupational Hearing Loss: Hearing loss is recordable when work-related and the worker's overall hearing level is 25 dB HL or more averaged at 2,000, 3,000, and 4,000 Hz; retest within 30 days permitted
4. OSHA, Penalties (civil penalty amounts adjusted for inflation 2024): Maximum serious violation penalty $16,131; maximum willful or repeated violation $161,323 as of January 2024; small employer penalty reductions up to 60%
5. Bureau of Labor Statistics, Injuries, Illnesses, and Fatalities program: Hearing loss is consistently among the most common occupational illnesses in manufacturing
6. OSHA, State Plans (list of approved state programs): 22 states and 2 territories operate State Plan programs; state standards must be at least as effective as federal OSHA standards
7. OSHA, Standard Interpretations on multi-employer and temporary worker responsibilities: Host employers control site conditions and share responsibility for temporary workers' hazard protection including noise; staffing agencies typically responsible for training not requiring site-specific knowledge
8. OSHA, 29 CFR 1910.95 Appendix A (Noise Exposure Computation): Dose formula for calculating combined noise exposure from multiple sources or areas: D = sum of (Cn/Tn); dose of 50% triggers Action Level, 100% triggers PEL
9. OSHA, 29 CFR 1910.95 Appendix B (Methods for Estimating the Adequacy of Hearing Protector Attenuation): Methods for derating NRR for real-world field attenuation; hearing protector must reduce exposure to at least 90 dBA (85 dBA for workers with STS)
10. OSHA, 29 CFR 1910.1020 Access to Employee Exposure and Medical Records: Audiometric records are medical records subject to confidentiality requirements under the access standard; separate from 300 log records
11. NIOSH, Sound Level Meter Apps (mobile phone apps do not meet ANSI standards): Smartphone apps are not validated to ANSI S1.4 specifications and are not acceptable for OSHA compliance monitoring
12. Council for Accreditation in Occupational Hearing Conservation (CAOHC), Certification requirements for audiometric technicians: Audiometric testing technicians must be CAOHC-certified or supervised by a licensed audiologist or physician under 29 CFR 1910.95