Foundry operations — sand casting, investment casting, die casting, and lost foam — generate extreme noise from shakeout and knockout operations, grinding, shot blasting, sand handling, and the continuous din of molding equipment. Foundry workers face some of the highest occupational noise exposures documented in NIOSH field studies, with shakeout operations routinely measuring above 105 dBA. The CDC estimates 22 million U.S. workers face hazardous occupational noise each year, and foundry workers are a meaningful segment of that total.
Soundtrace provides automated audiometric testing, real-time noise monitoring, and HPD fit testing in a unified platform for employers across the industries where foundry workers work.
Are Foundry Workers at Risk of Hearing Loss?
Yes — foundry workers work in environments where shakeout tables, shot blast machines, grinding operations, molding machines, and sand handling equipment regularly produce noise levels of 88–118 dBA. Sustained exposure at these levels causes permanent, irreversible noise-induced hearing loss (NIHL). OSHA requires employers to enroll workers whose 8-hour TWA meets or exceeds 85 dBA in a hearing conservation program.
How Common Is Hearing Loss Among Foundry Workers?
The CDC estimates 22 million U.S. workers face hazardous occupational noise each year, and foundry workers are a meaningful segment of that population. Many foundry workers develop a characteristic 4,000 Hz notch on audiometry within the first decade of unprotected exposure — often before they notice any functional hearing difficulty. Without annual audiometric testing, that early damage goes undetected until it has progressed significantly.
What Should Employers Do to Protect Foundry Workers’ Hearing?
Employers must implement a complete hearing conservation program including noise monitoring to document each worker’s TWA, baseline and annual audiograms to detect standard threshold shift, hearing protection fit testing to verify actual attenuation, and annual training. Documentation from day one of employment protects both workers and employers.
Can Foundry Workers File Workers’ Compensation Claims for Hearing Loss?
Yes. Occupational hearing loss is compensable in all 50 U.S. states. Workers’ compensation claims for hearing loss are routinely filed years or decades after the exposure period. Employers with a documented pre-employment audiogram are far better positioned to defend against or apportion these claims.
Foundry operations have one of the longest documented histories of occupational hearing loss of any industry. OSHA 1910.95 applies to all general industry foundry operations. OSHA has specifically cited foundries for hearing conservation deficiencies at rates disproportionate to their share of the manufacturing workforce — shakeout and grinding areas are consistent citation targets.
Measured Noise Exposure Levels
| Operation | Typical Noise Level | OSHA Max Duration |
|---|---|---|
| Shakeout / knockout (casting removal) | 105–118 dBA | Under 30 minutes |
| Shot blast / tumble blast | 100–112 dBA | Under 2 hours |
| Grinding / chipping (casting cleanup) | 98–108 dBA | Under 2 hours |
| Molding machine (jolt-squeeze) | 100–112 dBA | Under 2 hours |
| Sand muller / mixer | 90–100 dBA | 2–4 hours |
| Core making (hot box) | 88–98 dBA | 2–4 hours |
| Pouring / ladle operations | 92–102 dBA | 2–4 hours |
| Foundry floor ambient | 90–100 dBA | 2–4 hours |
OSHA Requirements
Under 29 CFR 1910.95, employers must implement a hearing conservation program when any worker's 8-hour TWA meets or exceeds 85 dBA. Required elements:
- Noise monitoring to establish documented TWA for each exposed worker
- Baseline audiogram within 6 months of first exposure at or above the action level (preceded by 14 hours of quiet)
- Annual audiograms compared to baseline for standard threshold shift (STS) detection
- Hearing protection provided at no cost in a variety of types and styles
- Annual training covering noise hazards, HPD use, and audiometric results
- Recordkeeping per 1910.95(m) — noise measurements, audiograms, training documentation
See: OSHA 1910.95: All 6 Elements Explained
Shakeout: The Highest Single-Source Noise Exposure in Foundry Operations
Shakeout — the process of separating hardened casting from the sand mold using vibrating grates or tumbling drums — is consistently the loudest operation in any foundry. At 105–118 dBA, unprotected exposure during a shakeout cycle can cause permanent cochlear damage within minutes. Workers who operate or work near shakeout equipment without fit-verified double hearing protection are accumulating irreversible cochlear damage with every shift.
Noise control at shakeout is possible through acoustic enclosures, remote operation, and vibration isolation — but these controls require capital investment that many foundries have historically deferred. Where engineering controls are not feasible above the PEL, OSHA 1910.95 requires reliance on hearing protection with verified adequate attenuation.
A foundry worker who spent 15 years near shakeout operations without hearing protection carries cochlear damage that is among the most severe documented in any occupational population — and the audiometric record that would allow the employer to defend against a WC claim almost certainly doesn't exist.
See: Hearing Protection Fit Testing: What Employers Need to Know and Workers' Compensation for Occupational Hearing Loss
Workers' Compensation Exposure
Occupational hearing loss WC claims are routinely filed years or decades after the causative exposure. Without a documented baseline audiogram, employers cannot establish what hearing the worker had at hire — making every dB of loss present at claim filing presumptively attributable to the current employer.
A complete audiometric record, maintained from day one of employment, is the only document that allows an employer to separate their noise exposure period from everything that came before and after.
See: Workers' Compensation for Occupational Hearing Loss and Noise-Induced Hearing Loss: The Employer's Complete Guide
Frequently Asked Questions
Yes, when their 8-hour TWA meets or exceeds 85 dBA. Most foundry workers in active work environments regularly exceed this threshold. OSHA 1910.95 requires employers to enroll qualifying workers in a hearing conservation program including audiometric testing, hearing protection, training, and recordkeeping.
Noise-induced hearing loss (NIHL) is the primary occupational hearing condition. It typically presents first as a 4,000 Hz notch on audiometry before progressing to involve 3,000 and 6,000 Hz. The loss is permanent and irreversible once established, which is why early detection through annual audiometry is critical.
Yes. Occupational hearing loss is compensable in all U.S. states when a worker can establish that their hearing loss was caused or contributed to by workplace noise exposure. Claims are routinely filed years or decades after the exposure period. Employers with complete audiometric records and documented noise measurements are far better positioned to contest causation or support apportionment.
A compliant hearing conservation program includes noise monitoring to document TWA, baseline and annual audiograms, hearing protection provided at no cost, annual training, and complete recordkeeping. Individual HPD fit testing — measuring each worker's personal attenuation rating (PAR) — is the only method that verifies actual protection rather than assuming label NRR performance.
Hearing protection must provide adequate attenuation for the actual measured TWA. Individual fit testing verifies each worker's personal attenuation rating (PAR). At higher exposure levels, double protection — earplug combined with earmuff — may be required to achieve adequate attenuation.
In-house audiometric testing for foundry operations
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