OSHA Occupational Noise Exposure and Hearing Conservation Compliance in Manufacturing: What Inspectors Are Looking For

Every year, manufacturing plants across the country receive OSHA inspections where the compliance officer walks in, confirms the NAICS code on the way through the front door, and starts evaluating one thing: whether the employer has a functioning hearing conservation program. Not whether the plant is noisy — it almost certainly is. Whether the program built around that noise meets the requirements of 29 CFR 1910.95.

Noise-induced hearing loss is the most commonly recorded occupational illness in U.S. manufacturing.¹ It is also one of the most preventable, and one of the most consistently cited. OSHA Region 5 — covering Illinois, Indiana, Michigan, Minnesota, Ohio, and Wisconsin — spent five years running a Regional Emphasis Program (REP) specifically targeting manufacturing industries with above-average hearing loss rates. That REP, CPL 04-00-27, was active from June 1, 2021 through May 31, 2026.² It expired just days before this article was published.

Whether a renewal is coming, and when, is worth watching. But the more important point is this: the underlying standard never expires. 29 CFR 1910.95 applies to every general industry employer in the country where workers are exposed to occupational noise at or above 85 dBA as an 8-hour time-weighted average. The REP just meant Region 5 was scheduling inspections proactively against manufacturers instead of waiting for complaints. The standard itself has been on the books since 1971.

If your plant is in manufacturing — anywhere in the country — here is what OSHA’s framework requires, where the common gaps are, and one critical thing most plant managers misunderstand about what “compliant” actually means.

The Two Numbers That Drive Everything: 90 dBA and 85 dBA

29 CFR 1910.95 establishes two separate thresholds, and they trigger different obligations.³

The permissible exposure limit (PEL) is 90 dBA as an 8-hour time-weighted average. This is the legal ceiling — the maximum allowable average exposure across a shift. The standard uses a 5 dB exchange rate: for every 5 dB increase in level above 90 dBA, the allowable exposure duration is cut in half. At 95 dBA, you get 4 hours. At 100 dBA, 2 hours. At 115 dBA, 15 minutes. Exposure above these limits is a direct violation.

The action level (AL) is 85 dBA — also an 8-hour TWA, representing 50% of the allowable dose. This is the trigger for the full hearing conservation program. An employer does not have to exceed the PEL for OSHA to require a complete program. If workers are averaging 85 dBA or more across their shift, the employer owes them monitoring, annual audiograms, hearing protectors, training, and documented recordkeeping. All of it.

The distinction matters because most noise-related citations in manufacturing are not PEL overexposures. They are hearing conservation program deficiencies at facilities where workers are operating between 85 and 90 dBA — above the action level, below the ceiling — and the program built around that exposure is incomplete or undocumented.

What the Hearing Conservation Program Requires (and Where Employers Miss)

A compliant hearing conservation program under 29 CFR 1910.95(c)–(o) has six operational components. When an OSHA compliance officer arrives under the Region 5 REP — or any noise-focused inspection — this is what they are evaluating.

1. Noise Monitoring

The employer must measure employee noise exposures when information indicates exposures may be at or above the action level. The monitoring methodology must integrate all noise from 80–130 dBA, including continuous, intermittent, and impulsive sources. Employees and their representatives have the right to observe monitoring.³

The gap most often missed: area surveys using a sound level meter on a tripod do not satisfy this requirement for workers whose tasks carry them between areas or who work near intermittent high-noise sources. Personal noise dosimetry — a calibrated dosimeter worn by the worker through a full representative shift — is the standard that holds up under inspection. Many plants have done a single area survey, logged the results, and treated the box as checked. It isn’t.

2. Audiometric Testing

Annual audiograms are required for all employees exposed at or above the action level. Before the first (baseline) audiogram, the employee must have had at least 14 hours away from workplace noise — or must have worn hearing protection during those 14 hours. The testing must be performed by or under the supervision of an audiologist, otolaryngologist, or physician.³

The baseline is the reference point for everything that follows. If the baseline was taken at the wrong time — say, at the start of a shift after the employee had just spent 8 hours on the line — the comparison audiograms will look better than they should, and real hearing loss will be missed until it’s advanced.

3. Standard Threshold Shift Tracking

This is where many plants have a documentation problem they don’t know about.

A Standard Threshold Shift (STS) is defined as an average shift in hearing threshold of 10 dB or more at 2000, 3000, and 4000 Hz in one or both ears, compared to the baseline.⁴ When an annual audiogram shows an STS, the employer has 21 days to notify the employee in writing, refit or fit hearing protectors, and retrain. If the STS is work-related AND the employee’s total hearing level is 25 dB or more above audiometric zero (averaged at the same frequencies, same ear), it is recordable on the OSHA 300 Log under 29 CFR 1904.10.⁵

Here is the exposure: an employer running annual audiograms without a formal process for identifying STSs, notifying employees, updating protector selection, and tracking 300 Log obligations is sitting on a recordkeeping violation that may not surface until an inspector pulls the audiometric files and compares them to the 300 Log. The audiometric testing vendor does not automatically file the 300 Log entry. That obligation belongs to the employer.

4. Hearing Protector Program

Hearing protectors are required for employees exposed at or above the action level who have not yet received a baseline audiogram, and for all employees exposed above the PEL.³ Protectors must provide sufficient attenuation to bring exposure to at or below 90 dBA — or 85 dBA for employees with an existing STS.

The employer must evaluate the adequacy of the protector’s attenuation, not just issue earplugs and call it done. OSHA guidance and the NIOSH derating methods provide the framework. “We have foam earplugs available” is not a hearing protection program.

5. Annual Training

Training is required annually for all employees exposed at or above the action level. It must cover: the effects of noise on hearing, the purpose and proper use of hearing protectors (including advantages, disadvantages, and attenuation characteristics), and the purpose and procedures for audiometric testing.³

Training conducted once at hire and never refreshed, or documented only as a roster with no content verification, does not satisfy this requirement.

6. Recordkeeping

Noise exposure measurements must be retained for at least 2 years. Audiometric test records must be retained for the duration of the affected employee’s employment.³ These records are one of the first things a compliance officer requests during a noise inspection.

What the Region 5 REP Targeted and Why It Matters Beyond Region 5

CPL 04-00-27 targeted manufacturing establishments in NAICS super sectors 32 and 33 with hearing loss rates at or above the national manufacturing average of 8.6 cases per 10,000 full-time workers.² That covers a significant portion of the industrial manufacturing base: primary metals and foundries (331xxx), forging and stamping (3321xx), fabricated metal products (332xxx), metalworking machinery (3335xx), wood products (321xxx), paper manufacturing (322xxx), transportation equipment (336xxx), and furniture (337xxx), among others.

Region 5’s prior enforcement data tells the story clearly: between FY 2013 and FY 2019, OSHA Region 5 issued 759 citations under 29 CFR 1910.95 in manufacturing — an average of roughly 108 per year before the REP was even launched.² The REP added programmed inspections on top of complaint-driven activity.

The standard is national. A manufacturer in Kansas, Texas, or the Pacific Northwest is operating under the same 29 CFR 1910.95 requirements. The Region 5 REP focused enforcement resources in the Midwest, but there are parallel emphasis programs in other regions and the underlying citation exposure is the same regardless of geography. A serious violation under 29 CFR 1910.95 carries a maximum penalty of $16,550 per violation. A willful or repeated violation — say, a failure to correct identified deficiencies after a prior inspection — carries up to $165,514 per violation, with a minimum of $11,823.⁶

That math changes quickly when an inspector finds four or five discrete HCP failures at a single facility.

The Limit OSHA Set Is Not the Limit That Protects Hearing

This is the part most plant managers have not heard, and it changes how you should think about program design.

OSHA’s 90 dBA PEL and 5 dB exchange rate are not the most scientifically protective standards on the table. They are the standards that OSHA determined were feasible to enforce at scale in 1971. NIOSH, the research agency, has recommended a different approach since 1972 — updated formally in 1998: an 85 dBA recommended exposure limit (REL) with a 3 dB exchange rate, based on the equal-energy principle.⁷

The difference is significant. OSHA’s 5 dB rule means that at 95 dBA, an employer can expose a worker for 4 hours and stay compliant. NIOSH’s 3 dB rule — based on the actual physics of how sound energy accumulates in the cochlea — would allow just under 2 hours at 94 dBA. At 100 dBA, OSHA permits 2 hours; NIOSH recommends 15 minutes.

The practical implication: a manufacturer running a hearing conservation program calibrated to OSHA’s action level, with protectors that attenuate to just below the PEL, can still have workers accumulating hearing damage over a career. NIOSH acknowledges that even its own more-protective 85 dBA REL does not protect every worker — approximately 8% of workers exposed at the REL over a 40-year career will still develop measurable hearing loss.⁷

OSHA compliance is the legal floor. It is not a guarantee that workers’ hearing is protected, and it is not a defense in a workers’ compensation or tort proceeding. Designing a hearing conservation program around the OSHA action level produces a compliant program. Designing around NIOSH’s REL with the 3 dB exchange rate produces a defensible one.

This distinction matters to plant managers and EHS directors who are responsible for both regulatory compliance and actual workforce health outcomes. The standard you meet for OSHA and the standard that demonstrates due diligence in a hearing loss claim are not necessarily the same number.

Running the Audit Before OSHA Does

Before the next inspection cycle, whether under a renewed Region 5 REP or a complaint-driven inspection, the useful exercise is to walk through your facility the way a compliance officer would. Start with the question OSHA starts with: is there any noise monitoring data that indicates potential exposures at or above 85 dBA?

If the answer is yes — or if you’re operating stamping presses, grinders, saw lines, high-speed machining centers, metal forming equipment, packaging lines, or any of the other equipment categories that routinely produce exposures in the 85–100 dBA range — then the full program should be in place and documented.

The six-part audit:

Do you have personal noise dosimetry data on the workers with the highest potential exposures, from a full representative shift, collected within the last two years?
Is an audiometric testing program in place with baseline and annual audiograms for all exposed employees, performed by or under qualified supervision?
Do you have a formal STS identification and response process — written, with defined responsible parties and timelines?
Is hearing protector selection documented, with attenuation adequacy evaluated for the actual noise levels in each area?
Is annual training documented with content records — not just a sign-in sheet?
Are audiometric records and noise monitoring results retained as required and accessible for inspection?

If the answer to any of those is “I think so” or “we did that a few years ago,” that is where the risk lives.

Where iSi Fits

iSi Environmental’s industrial hygiene team has conducted noise sampling across manufacturing environments in 40 states — stamping operations, food processing lines, wood product mills, foundries, fabrication shops. The work is not complicated, but it has to be done correctly: calibrated equipment, full-shift monitoring on representative tasks, documented methodology, and a report that gives the plant manager actionable exposure data rather than a binder of numbers.

A noise dosimetry assessment that establishes which workers are above the action level, which are near the PEL, and what the current program gaps are typically starts at $4,050.⁸ That is the number that tells you whether you need an engineering controls analysis, whether your current protectors are adequate, and whether your audiometric program is structured to catch STSs before they compound into recordable cases.

Hearing conservation programs are not one-time projects. They require ongoing management: annual audiogram scheduling and review, STS tracking and 300 Log obligations, protector re-evaluation when processes or equipment change, and annual training documentation. iSi’s COOP retainer is built for exactly this kind of recurring industrial hygiene work — program management that stays current with the facility, not a report that ages on a shelf.

If you are in a Region 5 manufacturing facility wondering whether a renewed noise REP is coming, the answer is: probably. But the more useful question is whether your current program would hold up under the six-part inspection the compliance officer walks through when they arrive. That answer is available now, before they do.

Call iSi at (316) 264-7050 or contact the industrial hygiene team directly to schedule a noise dosimetry assessment and hearing conservation program review.

Sources

OSHA Occupational Noise Exposure overview: https://www.osha.gov/noise ↩
CPL 04-00-27, OSHA Region V Regional Emphasis Program for Exposure to Noise Hazards in the Workplace, effective June 1, 2021, expiration May 31, 2026: https://www.osha.gov/sites/default/files/enforcement/directives/CPL_04-00-27.pdf ↩ ↩² ↩³
29 CFR 1910.95 — Occupational noise exposure (eCFR): https://www.ecfr.gov/current/title-29/subtitle-B/chapter-XVII/part-1910/subpart-G/section-1910.95 ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶
29 CFR 1910.95, OSHA standard page: https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.95 ↩
29 CFR 1904.10 — Recording criteria for cases involving occupational hearing loss (eCFR): https://www.ecfr.gov/current/title-29/subtitle-B/chapter-XVII/part-1904/subpart-C/section-1904.10 ↩
OSHA Penalties (current amounts effective January 15, 2025): https://www.osha.gov/penalties ↩
NIOSH Science Bulletin: Understanding Noise Exposure Limits: Occupational vs. General Environmental Noise (2016): https://www.cdc.gov/niosh/bulletin/2016/noise.html — and NIOSH Criteria Document 98-126 (1998): https://www.cdc.gov/niosh/docs/98-126/ ↩ ↩²
iSi Environmental industrial hygiene assessment pricing from proposal catalog: median IH project $4,050. See brand-voice.md Section 3 and Section 14 (cost asymmetry anchor #2). ↩