- 30 million workers in the US face significant exposure to hazardous noise.
- Hearing can be damaged by a single extremely loud sound or by prolonged exposure to a noisy environment.
- Hair cells in the inner ear are responsible for converting sound into electrical impulses that travel to the brain to be processed.
- Hearing loss is, in part, caused by damage to inner ear hair cells.
- Noise-induced hearing loss in the work place can be prevented by the introduction of effective hearing conservation programs.
- Noise levels are measured in decibels (dB).
- Workers who are exposed to 85dBA TWA over an average of 8 hours must be monitored, tested and protected.
- OSHA hearing conservation standards are designed to protect workers from noise induced hearing loss.
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Why is hearing conservation so important?
It is estimated that over 30 million workers in the US are exposed to hazardous noise that puts their hearing at risk. One incident of explosive noise can have an immediate damaging effect, while exposure to harmful noise over prolonged periods of time can result in gradual hearing loss and tinnitus (ringing, whistling, humming or buzzing in the ears). OSHA hearing conservation standards have been implemented to protect workers from noise induced hearing loss.
How does hearing damage occur?
The ear is a complex structure and is highly sensitive. Sound travels through the outer and middle ear canal toward sensory hair cells within the inner ear. The inner ear hair cells convert sound waves into electrical impulses that then travel to the brain to be processed and understood as sound, speech, music, environmental sounds, etc. When exposed to long periods of noise or a short loud sound, the hair cells become damaged and cannot process sound effectively. Once destroyed, they can never be repaired, and therefore a person’s hearing can never be restored. Although research suggests that this hair cell damage may be medically treatable or preventable in the next 20-30 years, at this point in time, noise induced hearing loss is irreversible.
Noise-induced hearing loss can be prevented by effective hearing conservation programs for ‘at-risk’ employees. The OSHA website (www.osha.gov) has excellent information related to noise measurement and control as well as OSHA hearing conservation programs. Employers should be familiar with specific standards for recordkeeping and the general industry, including 1910 Subpart G, ‘Occupational health and environment control’ of which 1910.95 is titled ‘Occupational noise exposure’. These regulations outline the maximum noise levels and duration that workers are exposed to before monitoring and hearing conservation programs should be administered and explain how and when noise induced hearing loss and injuries should be reported/recorded.
Helpful Resources Regarding OSHA Hearing Conservation Standards:
29 CFR 1910.95 – Occupational Noise Exposure.
29 CFR 1904 Recordkeeping
30 CFR Part 62 – Occupational Noise Exposure
30 CRR Part 50 – Reporting
49 CFR Parts 227 – Occupational Noise Exposure
49 CFR Parts 225 – Reporting and Recordkeeping
Monitoring your workers
It is important for employers to evaluate noise levels at work, identify employees at risk and determine if a hearing conservation program is necessary. For those who are exposed to noise levels of 85dB or more over an 8-hour period, monitoring is essential. Employers of workers who experience those levels are required to carry out an audiometric testing program to monitor workers’ hearing over time. A baseline audiogram is required within six months of a worker first becoming exposed to those levels. Audiometric testing must be carried out within one year of the baseline audiogram and then annually to detect deterioration. For workers enduring 85dB or more over eight hours, hearing protectors such as plugs must be worn. Employers must implement an effective hearing conservation program consisting of:
- Audiometric testing and analysis
- Hearing protection fitting, use and supervision
- Employee training
American Academy of Audiology
American Academy of Audiology
National Institute for Occupational Safety and Health
Nat Inst for Occ Safety & Health
Business Owner Briefing
Hearing Conservation. OSHA 3074 2002 (revised)
Medical Director Review
Original paper: Occupationally acquired noise-induced hearing loss: a senseless workplace hazard by Kurmis and Apps, 2007.