Hearing loss is a common occupational hazard for many workers. Prolonged exposure to loud noise on the job can damage the inner ear and cause permanent hearing damage over time. Unfortunately, once hearing loss occurs, it is irreversible. However, preventing occupational hearing loss is possible through appropriate use of hearing protection, monitoring noise levels, and limiting exposure.
What is occupational hearing loss?
Occupational hearing loss refers to hearing damage caused by prolonged exposure to hazardous noise at work. It can be caused by a single extremely loud noise, like an explosion, or by repeated exposure to noises at or above 85 decibels over an extended period. Examples of workplace noises that can lead to hearing damage include:
- Heavy equipment like tractors, backhoes, and jackhammers
- Power tools such as chainsaws, table saws, and pneumatic tools
- Loud music and concerts
- Gunfire and artillery in the military
- Aircraft and jet engines
- Factory machinery and assembly lines
The Occupational Safety and Health Administration (OSHA) regulates permissible noise exposure in the workplace. The maximum allowable noise exposure over an 8 hour shift is 90 decibels. For every 5 decibel increase above 90 dB, the allowed exposure time is cut in half. So at 95 dB, the max exposure is 4 hours. At 100 dB, only 2 hours is permitted.
What are the stages of noise-induced hearing loss?
Noise-induced hearing loss typically develops gradually, in three main stages:
- Temporary threshold shift – Exposure to loud noise leads to temporary, reversible hearing loss that resolves in 16-48 hours after leaving the noisy environment. Although hearing recovers, repeated temporary threshold shifts can lead to permanent damage.
- Permanent threshold shift – Long term occupational noise exposure causes permanent sensory cell damage in the inner ear, leading to irreversible hearing loss. Those with a PTS still have some hearing, but it is reduced. The higher pitches are affected first.
- Absolute deafness – After years of excessive noise exposure, the sensory cells are completely destroyed, leading to profound or “absolute” hearing loss and deafness.
What noise levels can cause hearing damage?
In general, prolonged exposure to any noise over 85 decibels (dB) can cause gradual hearing damage. Loudness is measured on a logarithmic scale, so a small increase in decibels results in a huge jump in sound pressure level and potential harm to hearing. For reference, here are the approximate noise levels of some common sound sources:
| Noise source | Noise level (dB) |
|---|---|
| Whisper | 30 |
| Normal conversation | 60-65 |
| Lawnmower | 90 |
| Motorcycle | 95 |
| Power saw | 105 |
| Ambulance siren | 120 |
| Military jet takeoff | 140 |
Noise levels above 120 dB can immediately damage hearing from a single exposure. But the majority of occupational hearing loss is caused by repeated medium to high noise exposure over time. Noise dosimeters can be worn to measure an employee’s cumulative noise exposure over a work shift.
Which occupations are most at risk for noise-induced hearing loss?
Workers in many industries are at significant risk of developing occupational hearing loss. Jobs with the highest rates of hearing damage include:
- Construction workers – equipment like jackhammers, saws, pneumatic air tools
- Airport ground crews – jet engines
- Entertainers, musicians – amplified music and concerts
- Landscaping and groundskeeping – leafblowers, lawnmowers, chainsaws
- Manufacturing and factory workers – machinery, generators, assembly lines
- Miners – drills, explosives
- Railroad workers – engines, horns, signals
Other high risk jobs include firefighters, auto mechanics, electricians, metal workers, machinists, woodworkers, and military personnel. According to OSHA estimates, about 30 million U.S. workers are exposed to hazardous noise on the job.
Construction Workers
Construction workers frequently use loud power tools and heavy machinery on job sites. Jackhammers and concrete saws produce noise levels over 100 dB. Even with short exposure times, this can cause hearing damage quickly. Other construction noises – like bulldozers, backhoes, and nail guns – may be lower level but still hazardous with prolonged exposure day after day.
Airport Employees
Airport ground crews who work on the tarmac are routinely exposed to extreme jet engine noise. The high frequency whine of turbine engines can exceed 140 decibels at close proximity. Most ramp agents wear hearing protection, but many still experience significant hearing loss over time.
Performing Artists and Musicians
Musicians are vulnerable to hearing damage both on stage and when practicing amplified music for hours on end. Even orchestra members can suffer hearing loss over years of close proximity to percussion and brass instruments. For professional singers, ear monitors may produce sound levels up to 105 dB directly into the ear canal for hours.
Landscaping and Groundskeeping
Landscapers use leaf blowers, mowers, trimmers, chippers, and chainsaws – all noisy equipment that poses risks. Electric models are quieter than gas-powered, but still produce high decibels. Proper protective equipment is critical, as hearing can be permanently damaged after just a few years of repetitive exposure.
Factory and Manufacturing Workers
Noise on factory and production floors routinely exceeds safe levels. Machinery like generators, pumps, gear assemblies, stamping presses, and robotic arms generate continuous hazardous noise. Depending on the equipment and plant design, sound levels can range from 80 to over 100 decibels.
How does hearing loss from work affect quality of life?
Unprotected exposure to occupational noise can lead to various degrees of hearing impairment. Effects on work and daily life include:
- Difficulty understanding conversations, especially with background noise
- Increased risk of accidents if warnings or alerts aren’t heard
- Social isolation and fatigue from straining to hear
- Reduced productivity and impaired work performance
- Depression and reduced overall health from effects of isolation
- Reduced earning capacity due to hearing-related limitations
Hearing loss can significantly impact worker safety, communication, job effectiveness, and quality of life. That’s why proper hearing conservation practices are critical.
How can workers prevent noise-induced hearing loss?
Preventing occupational hearing loss requires:
- Noise monitoring – Regularly measure noise levels throughout the facility and worker noise exposures. Identify problem areas.
- Hearing protectors – Provide proper protective equipment like earmuffs and plugs. Ensure they are worn in required high noise areas.
- Reduce noise emissions – Use engineering controls to reduce machinery and equipment noise outputs.
- Maintenance – Keep equipment well maintained to prevent excessive noise. Fix or replace defective mufflers, bearings, etc.
- Job rotation – Rotate workers between high and low noise tasks to limit exposures.
- Enclosed work stations – Isolate noisy processes in acoustical enclosures.
- Awareness training – Educate workers on noise hazards and ways to protect their hearing.
- Annual hearing tests – Monitor worker’s hearing sensitivity to identify problems early.
Implementing a comprehensive hearing loss prevention program can successfully protect worker’s hearing health over the long term.
What kinds of hearing protection can workers use?
There are various types of hearing protectors available for workplace use, including:
- Earplugs – Inserts that fit into the ear canal to block noise. Different materials like foam, rubber, plastic, and custom molded plugs.
- Earmuffs – Fit over the entire ear to form an acoustic seal. Provide the highest noise reduction rating.
- Helmets – Some hard hats integrate muffs or plug attachments for hearing protection.
- Communication headsets – Special headsets allow face-to-face and radio communication while still protecting hearing.
Hearing protectors must be properly fitted and worn consistently in required areas to be effective. Regular inspections should ensure compliance. The optimal protector depends on noise levels, type of work, and individual needs.
When is medical treatment needed for hearing loss?
If a worker experiences sudden onset of reduced hearing or severe ear pain after high noise exposure, prompt medical evaluation is required. Temporary or permanent sensorineural hearing loss may have occurred.
Ruptured eardrum symptoms like drainage or bleeding from the ear canal also warrant immediate medical attention.
For gradual onset of hearing reduction, the worker should have regular hearing tests through an occupational health clinic. The doctor can assess if hearing loss is noise-induced and make treatment recommendations. These may include:
- Prescription hearing aids to improve hearing and communication
- Education on avoiding further noise damage
- Adjustment of work duties to limit noise exposures
- Earplugs or earmolds to protect hearing during sleep and recreation
- Evaluation for cochlear implants if hearing loss is severe
Workers exposed to occupational noise should have annual hearing exams to monitor changes before impairment progresses. Research also continues on drugs or nutraceuticals that may help prevent noise-induced hearing loss in the future.
Are workers compensated for occupational hearing loss?
In most states, sensorineural hearing loss caused by excessive workplace noise is compensable through the workers’ compensation system. To receive benefits, the worker must prove that hearing damage occurred due to working conditions, not age or other causes. Compensation typically includes:
- Medical costs – Treatment expenses related to the hearing loss. Hearing aids, fittings, batteries, etc.
- Lost wages – Partial wage replacement for work time missed.
- Disability rating – A permanent partial disability (PPD) rating, if hearing loss is severe. This results in a lump sum payment.
Hearing loss claims are complex. State laws vary widely. An experienced attorney can help affected workers pursue the maximum benefits available for their level of impairment.
Conclusion
Noise-induced hearing loss is entirely preventable with proper hearing conservation programs. When excessive workplace noise can’t be controlled, workers must be provided adequate protective equipment and training. Through awareness, monitoring, and safety practices, employees can avoid permanent ear damage and hearing impairment over the course of a career working in hazardous noise.