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Occupational noise deserves attention before a hearing test shows a change. Noise can interfere with warnings and communication, and research examines its relationship with stress and cardiovascular health. The practical question is how to use that evidence without claiming more than a study can establish.
This article examines the methods and reporting in a steel-industry study by Sakthivel and colleagues, then connects the evidence with workplace assessment and control verification. It is an applied research critique, not a new field investigation or a systematic review.
What does “beyond hearing loss” mean?
Nonauditory effects concern outcomes other than hearing damage. NIOSH’s prevention guidance identifies associations with high blood pressure and cardiovascular disease, alongside concerns about stress, fatigue and reduced awareness of alarms or verbal warnings. These are different questions from whether an audiogram has changed. Tinnitus remains an auditory concern.
A useful assessment therefore asks about exposure, communication and working conditions as well as hearing conservation. A normal hearing test does not establish that a noisy task allows reliable communication. A report of fatigue does not, by itself, identify noise as its cause. Each observation needs an appropriate follow-up.
What the steel-worker study examined
Sakthivel and colleagues (2025) reported a cross-sectional study of 80 male steel workers in Salem, India, using data collected in January 2022. The methods excluded 60 workers with specified pre-existing medical conditions or medication use. Participation also reflected willingness, management constraints and limited measurement resources.
The researchers collected workplace noise measurements, blood-pressure and heart-rate readings, and symptom reports. Table 1 separates 54 higher-exposure participants from 26 lower-exposure participants using an 85 dBA dividing point. The comparison group was exposed to lower noise; it was not a group with no noise exposure.
This combination offers information about a particular workforce and work period. It does not provide a trial of a noise-control intervention. Excluding workers with existing conditions also limits application to a workforce that includes those conditions.
Read the reporting conflicts before repeating the conclusion
The paper reports some cross-shift physiological differences, but its results do not support a simple statement that every higher-exposure group had higher readings. In Table 1, the higher-exposure group’s mean systolic pressure is 134 mmHg, compared with 146.2 mmHg in the lower-exposure group; the heart-rate means also run in that direction. The abstract’s 57% exposure-exceedance figure differs from Table 1’s 54 of 80 grouping, which equals 67.5%.
These are unresolved reporting differences in the published material reviewed here. I have not relabelled the groups, selected a preferred percentage or reconstructed a cardiovascular risk estimate. The study remains useful for identifying assessment questions, but those conflicts reduce confidence in an uncomplicated summary of its findings.
| Evidence | Question it can inform | Conclusion it does not establish |
|---|---|---|
| Workplace sound measurements | Which tasks or locations need closer exposure assessment? | Every worker’s full-shift personal dose. |
| Readings collected across a shift | Did the measured physiological indicators change during that period? | That noise alone caused the change or a future disease. |
| Worker symptom reports | What concerns and work patterns deserve investigation? | A medical diagnosis or a confirmed cause. |
| Differences between exposure groups | Is there a relationship worth examining with better measurement and comparison? | A control’s effectiveness or a prediction for another workforce. |
Why a cross-shift change is not a long-term disease finding
Taking measurements before and after a shift adds a time comparison. It does not turn an observational study into an experiment. Ask whether the analysis adequately distinguishes noise from physical effort, heat, work schedules and other relevant differences. The plant’s tasks and worker selection matter alongside the number of measurements.
Short-term heart-rate or blood-pressure readings and long-term cardiovascular disease are different outcomes. This study did not follow workers over years to measure new disease or test whether a particular control reduced it. My earlier critique extended the findings too far when it described demonstrated chronic effects and broadly consistent departmental results.
The methods also acknowledge limited personal noise-dosimeter availability. Area measurements can locate a noisy source, but interpreting individual exposure requires the worker’s movements, task duration and relevant instrument settings. Repeated readings at a location do not create additional independent workers in the sample.
Place the case study within the wider evidence
A WHO/ILO systematic review by Teixeira and colleagues (2021), searching through April 2019, rated the evidence for developing ischaemic heart disease as limited evidence of harmfulness. For the other cardiovascular outcomes it evaluated, including hypertension, the evidence was inadequate to determine harmfulness confidently. The review rated the evidence quality as low.
Those judgments describe the review’s included evidence and search period; they are not a complete account of all later research. Inadequate evidence is also different from evidence of no effect. Neither that review nor the later steel-worker study supplies a basis for predicting an individual worker’s illness or promising a measured disease reduction from a particular enclosure or hearing protector.
The reason to address hazardous noise does not depend on resolving every cardiovascular question. Hearing protection, exposure reduction and reliable work communication remain practical prevention concerns. Preserve that distinction when explaining why action is needed.
Use the correct OSHA and NIOSH benchmarks
For U.S. manufacturing work covered by federal general-industry requirements, distinguish 29 CFR 1910.95 from NIOSH recommendations. The 85 dBA figure is not a universal instantaneous legal ceiling or a diagnostic threshold for cardiovascular disease.
| Benchmark | Basis | Meaning |
|---|---|---|
| Federal OSHA hearing-conservation action level | 85 dBA, eight-hour time-weighted average; exposure calculated without hearing-protector attenuation. | Triggers the continuing hearing-conservation program under 1910.95(c). |
| Federal OSHA permissible exposure table | 90 dBA for eight hours; a 5 dB exchange relationship. | 1910.95(b) requires feasible engineering or administrative controls when Table G-16 exposures are exceeded, with protection as specified. |
| NIOSH recommended exposure limit | 85 dBA for eight hours; a 3 dB exchange rate. | A prevention recommendation, distinct from the federal OSHA limit. |
NIOSH explains that each 3 dB increase halves its recommended exposure duration. Record the criterion and exchange rate when interpreting a dose. A spot reading is not automatically an eight-hour average. Construction, other sectors and State Plan requirements need their own applicability review.
Assess the source and the communication problem
Begin with the task: equipment operating, worker position, time spent nearby and changes during the shift. Ask workers where speech, alarms or equipment cues become difficult to distinguish. NIOSH distinguishes sound-level measurements from personal dosimetry; use a suitable measurement plan rather than treating a noise map as every worker’s exposure record.
NIOSH’s Buy Quiet guidance encourages comparing quieter equipment options. Use comparable operating conditions when judging alternatives. A proposed quieter machine or source control needs evidence that it reduces exposure in the intended work, not just a lower number in an unrelated specification.
Hearing protection must also fit the worker and task. NIOSH recommends individual fit testing and considering communication, compatibility and comfort. A package rating is not the protection demonstrated for an individual worker. Selecting the greatest attenuation without considering necessary communication can create another practical problem.
Illustrative example: a rolling-area complaint
This is an original fictional example, not a report from the steel study or an actual employer. A rolling-area crew reports fatigue and difficulty hearing instructions when nearby equipment runs. Management already has annual hearing-test records and boxes of earplugs. Those records do not answer whether the task’s current noise and communication arrangements are adequate.
The safety team arranges a qualified exposure assessment, records the operating conditions and involves the crew in identifying communication failures. It evaluates a source-control option and checks how essential warnings would function during representative work. It also reviews hearing-protector fit and task compatibility.
After implementation, the team repeats appropriate measurements under comparable conditions and checks communication with the affected workers. A quieter area reading would support a specific noise-reduction finding. It would not establish that fatigue was caused solely by noise or that cardiovascular disease had been prevented. Health concerns belong with appropriate occupational-health assessment; the example supplies no diagnosis or treatment protocol.
Record the evidence needed to close the action
The following record is my practical interpretation, not a validated scoring tool or a mandatory form. Keep individual health details within appropriate confidential health arrangements. The operational action record should focus on work conditions, controls and the evidence needed for a decision.
| Record | Evidence to retain |
|---|---|
| Task and exposure | Representative equipment state, worker location and duration; instrument settings, calibration and assessment limits. |
| Control and responsibility | Selected source or exposure control, responsible owner, resources and implementation date. |
| Communication | How necessary speech and warnings were checked under representative conditions, including hearing-protector use. |
| Verification | Comparable follow-up measurements, worker feedback, remaining uncertainties and the decision made. |
| Review trigger | Equipment, production, maintenance or task changes that require reassessment. |
The companion articles on research applicability and the industrial-hygiene worked case explain why study design, measurement and exposure benchmarks must remain attached to the conclusion. The same discipline applies here: act on the identified exposure and communication problem, and describe the result at the level the evidence supports.
The current Jenkins Industry Safety Journal collection is not peer reviewed. AI assistance supported development and editing of this article. No independent industrial-hygiene technical review, medical validation or field testing of the illustrative record is claimed.
References and source record
The supplied primary study, including its tables, was examined; its unresolved reporting differences are retained above. The focused references below support this critique and practice discussion. The reference list is a focused selection, not a fully audited or exhaustive evidence base. No raw participant data were available.
- Sakthivel, R., Perumal Kamalakannan, L., Shanmugam, R., & Venugopal, V. (2025). Nonauditory impacts of industrial noise exposures: A case study from a steel manufacturing industry. Safety and Health at Work, 16(2), 243–248.
- Teixeira, L. R., Pega, F., Dzhambov, A. M., Bortkiewicz, A., da Silva, D. T. C., de Andrade, C. A. F., Gadzicka, E., Hadkhale, K., Iavicoli, S., Martínez-Silveira, M. S., Pawlaczyk-Łuszczyńska, M., Rondinone, B. M., Siedlecka, J., Valenti, A., & Gagliardi, D. (2021). The effect of occupational exposure to noise on ischaemic heart disease, stroke and hypertension: A systematic review and meta-analysis from the WHO/ILO Joint Estimates of the Work-Related Burden of Disease and Injury. Environment International, 154, 106387.
- Occupational Safety and Health Administration. (n.d.). Occupational noise exposure. 29 CFR 1910.95. Federal general-industry scope; checked October 26, 2026.
- National Institute for Occupational Safety and Health. (2024, February 16). Preventing occupational noise-induced hearing loss.
- National Institute for Occupational Safety and Health. (2024, January 31). Understand noise exposure.
- National Institute for Occupational Safety and Health. (2024, February 16). Eliminate or reduce noise.
- National Institute for Occupational Safety and Health. (2024, January 31). Provide hearing protection.