Q. What level of sound, in the workplace, damages the ears?
A. Damage from noise exposure in the workplace is dependent on sound level, or number of decibels (dB) and length of exposure. Lower levels of noise can be tolerated longer than high levels. The general guideline is that workers should not be exposed to sound levels of 85 dB for more than 8 hours. For every 5 dB over 85, the time is reduced by half. So if levels are at 90 dB, then the exposure time is limited to 4 hours, and so on.
Q. Do the effects worsen over years and years of exposure?
A. The effects of noise exposure on hearing are additive, meaning the longer the exposure in increments and length of exposure over years will cause more damage. The onset of hearing loss can be delayed, gradual and progressive.
Q. What are symptoms you would experience if your ears have been damaged by this kind of workplace sound?
A. The main symptoms of continuous noise-induced hearing loss are tinnitus (ringing in the ears) and hearing loss. The ringing may be the first symptom, as hearing loss may not be obvious at first. Inability to understand conversations in places with background noise, like restaurants, or having to turn up the TV or phone may be the first noticed effects of hearing loss.
Q. What are some common noises in the city that could potentially serve as a threat and cause noise-induced hearing loss?
A. To give you an idea, here are some common noises, and their decibel levels, that individuals may experience:
- Dishwashers, normal conversation: 60 dB
- Vacuums, city traffic: 70 dB
- Power tools, lawnmowers, hair dryers: 90 dB
- Jet engine: 120 dB
- Jackhammer, sirens: 130 dB
Q. Which jobs have the greatest potential for noise-induced hearing loss?
A. Jobs with high noise exposure (in no particular order) are as follows:
- Manufacturing (factory floor, machine shops, printing presses)
- Transportation (jet engine noise, train yards, mechanics)
- Construction (general construction, machine operators, carpenters)
- Agriculture (farming equipment, mills)
- Hair dresser
Q. What can people do to protect their hearing at work?
A. There is no cure for noise-induced hearing loss, making hearing protection extremely important. There are three types of hearing protection devices: earmuffs, earplugs and semi-insert earplugs. Each of these devices has an NRR, or noise reduction rating, used to define the ability of a device to protect hearing from specific sound levels. The NRR should be listed on the packaging for each device. Many factors influence the selection of proper hearing protection for the workplace including NRR, comfort, ease of use and ability to still communicate in the workplace.
Work environments with time-weighted noise exposure over 85 dB are required to have a Hearing Conservation Program. When the time-weighted exposure is over 100 dB, both earmuffs and earplugs are recommended to be worn together.
Determining the proper NRR requirement for your workplace can be complicated. Detailed information can be found at www.ohsa.gov. For additional information, or to purchase custom-fitted hearing protection devices, contact Midwest Hearing Consultants at 630-668-2180.
About this week’s ENT Answers doctor: Christopher Hampson, MD
Dr. Christopher Hampson joined Midwest ENT Consultants in 2002. He specializes in ear, nose and throat problems of children and adults. He is available for inpatient and outpatient consults for adults, children and neonates at , Edward, and Central DuPage Hospitals. Dr. Hampson throughout his career has sought out opportunities to gain experience and serve communities with limited access to healthcare. He has volunteered in Lawndale and Maywood. He has worked at St. Jude Hospital in St. Lucia and at the Alaskan Native Medical Center in Anchorage.