Primary Metals Manufacturing (NAICS 331) generates occupational noise exposures that require mandatory OSHA 1910.95 hearing conservation programs at most facilities. Primary metals (NAICS 331) has among the highest per-company occupational hearing loss rates in BLS data. Electric arc furnace operations, rolling mills, and casting operations generate extreme noise According to CDC/NIOSH, approximately 22 million U.S. workers are exposed to hazardous occupational noise annually, and primary metals workers are among those with significant hearing loss risk from primary production operations.
Soundtrace delivers in-house audiometric testing and noise monitoring for primary metals operations — ANSI S3.1-compliant, automated STS detection, and licensed audiologist Professional Supervisor review.
Noise Levels by Process: NAICS 331
| Equipment / Process | Typical Level | Typical 8-hr TWA | OSHA Status |
|---|---|---|---|
| Electric arc furnace | 100–120 dBA | 95–108 dBA | Significantly exceeds PEL |
| Rolling mill (hot) | 95–110 dBA | 92–102 dBA | Exceeds PEL |
| Rolling mill (cold) | 90–105 dBA | 88–98 dBA | At or above PEL for adjacent workers |
| Extrusion press | 90–105 dBA | 88–96 dBA | At or above PEL |
| Shearing and cutting | 95–110 dBA | 90–100 dBA | At or above PEL |
| Cooling beds / runout tables | 90–100 dBA | 88–95 dBA | At or above action level |
| Maintenance / mechanical | 85–100 dBA | 85–92 dBA | At or above action level |
Primary metals (NAICS 331) has among the highest per-company occupational hearing loss rates in BLS data. Electric arc furnace operations, rolling mills, and casting operations generate extreme noise levels that make this sector a consistent OSHA enforcement priority. The most common violations mirror heavy manufacturing patterns: late baseline audiograms, annual audiogram schedule failures, and inadequate HPD for PEL-exceeding exposures.
OSHA 1910.95 Compliance Requirements
All primary metals workers at or above the 85 dBA action level must be enrolled in the full six-element OSHA 1910.95 hearing conservation program: noise monitoring, audiometric testing, hearing protection, training, recordkeeping, and access to information. Workers above the 90 dBA PEL also require a documented engineering controls assessment. See: audiometric testing for employers: complete guide.
OSHA Citation Patterns: NAICS 331
| Violation Type | Frequency | Typical Penalty Range |
|---|---|---|
| Late or missing baseline audiograms (1910.95(g)(5)) | Very high | $2,000–$7,000 |
| Annual audiogram schedule failures (1910.95(g)(6)) | High | $2,000–$7,000 |
| No noise monitoring — assumed below action level without data (1910.95(d)) | High | $1,000–$5,000 |
| No engineering controls assessment above PEL (1910.95(b)(1)) | Moderate | $3,000–$9,000 |
| Inadequate HPD for actual exposure levels (1910.95(i)) | Moderate | $2,000–$6,000 |
| Missing or incomplete training records (1910.95(k)) | High | $1,000–$4,000 |
Workers’ Compensation Exposure
Primary metals workers often develop hearing loss gradually across 20–30 year careers before filing WC claims. Multi-employer exposure is common as workers move between mills. Pre-employment baseline audiograms establishing hearing status at hire are the critical record for apportionment.
The primary defense tools: a pre-employment baseline audiogram establishing the worker's hearing at hire, continuous annual audiometric records with no gaps, noise monitoring documentation by job classification, and HPD provision and fit testing records. Without complete documentation, apportionment of hearing loss between employers or between occupational and non-occupational causes cannot be performed. See: workers’ compensation for occupational hearing loss.
Industry-Specific Considerations
Steel mill and aluminum smelter operations involve extreme noise environments where single HPD may be insufficient above 100 dBA. Individual fit testing confirms adequate attenuation for each worker's specific task-based exposure.
In-house audiometric testing for primary metals operations
Soundtrace delivers OSHA-compliant audiometric testing and noise monitoring for primary metals employers — automated STS detection, 30-year cloud retention, and licensed audiologist supervision.
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