Despite decades of regulations, noise-induced hearing loss continues to be one of the most common occupational injuries. More than 5,500 cases of lost-time accidents are associated with noise exposure each year in this country
Noise exposure has severe consequences for hearing. However, the physiological and behavioral damage caused by excessive noise must be considered.
In this interview with Brad Witt, audiologist and former director of hearing protection at Honeywell Safety Products, we learn more about noise exposure’s effects, causes, and solutions.
WHAT NOISE LEVELS CAN CAUSE HEARING DAMAGE?
Most occupational hearing loss occurs as a result of prolonged exposure over time – not just a single loud event. Experts have defined a population average of 85 decibels (dB) over an 8-hour workday as a maximum daily exposure limit; so many regulations use that criterion. But it is not a hard brick wall, rather just a line in the sand. Some people (by some estimates, 5-12% of the population) will suffer some permanent impairment in prolonged exposures even below 85 dB. For this reason, some employers will offer hearing protection in every area of work where noise levels exceed 80 dB. This protects workers who are most likely to suffer from hearing damage.
As a general rule, to determine if noise is dangerous, look at how you communicate. If you have to shout to be heard by someone an arm’s length away, the noise is likely to be hazardous. This means it is close to the 85 dB limit.
HOW WOULD A WORKER KNOW IF THEIR HEARING IS BEING DAMAGED?
The damage to hearing progresses so slowly that it’s difficult for most workers to detect the difference from one month to the next. Regular audiometric testing is one of the best methods of early detection for any shifts in hearing. That audiogram helps determine if the hearing loss is progressing faster than what would be expected from normal aging.
The early warning signs of noise damage are subtle: the clarity of conversation will be affected before the loudness. One of the most common complaints from those suffering from noise-induced hearing loss is, “I can hear you speaking, but I just can’t understand.” This is especially noticeable in background noise, such as a restaurant or meeting place. One of the other telltale signs of noise damage is tinnitus, or ringing in the ears. A little bit of ringing is normal in everybody – it comes and goes intermittently. But a worker with noise damage will often have continual ringing in the ears. It can be disruptive to sleep and solitude, and annoying for life. Temporary ringing after a loud noise exposure can be the ear’s method of warning us the noise was too loud. But if we are exposed to loud noise day in and day out, the temporary ringing becomes permanent.Protect your hearing with the VeriShield earmuffs
WHAT ARE THE OTHER EFFECTS OF HAZARDOUS NOISE EXPOSURE?
Hearing loss and tinnitus are the most common effects. However, there are other physiological and behavioral consequences caused by noise exposure.
Some workers have their psychological health affected. Unfortunately, the entire environment, friends and family, is affected. Problems of isolation, self-esteem and even depression can occur.
The Canadian Centre for Occupational Health & Safety provides a good resource describing many of these effects. In the workplace, the auditory effects include:
- Difficulty communicating verbally
- Concentration problems
- Reduced work performance
- Difficulty recognizing alarms
- Decreased vigilance
In many jobs, communication with co-workers and warning signal detection are critical to the operations and workers' safety.
High noise exposures in the workplace have also been correlated to non-auditory effects like cardiovascular functions. One Canadian study determined that heart problems were 2-3 times more likely in workers exposed to high noise. Fatigue, anxiety, and insomnia have all been correlated to high noise exposures. These symptoms are not always predictable in a cause-effect relationship, but higher correlation suggests noise plays some contributory role.
WHAT CAN WE DO TO MITIGATE THESE EFFECTS?
Good hearing protection reduces or eliminates almost all of these effects. Ideally, noise should be eradicated at the source through engineering means. This could be done by:
- Modifying the noisy equipment or process
- Insulating the workstation exposed to noise
- Installing soundproofing materials
But when that’s not possible, proper hearing protection is an excellent defense against noise. Workers who wear hearing protection at all times will be able to preserve their hearing for the rest of their lives.
The key to wearing hearing protection equipment is to test regularly and adequately. Then, they can easily be performed to determine what level of noise is blocked by the equipment in question.
These systems can, for example, tell the worker if an earplug is inserted correctly or if it is the wrong size.
For optimal protection, it is crucial to protect yourself consistently, both on and off the job.
Recreational exposure to noise can be just as dangerous as the noise encountered at work. Loud music, hunting, chainsaws, power tools, motorized sports—all can cause hearing damage as easily as machinery at work.
For these recreational exposures, there aren’t as many warnings as there are in the workplace. So, it is up to each individual to take responsibility for protecting their hearing.
Although prolonged exposure to noise is harmful to health, choosing protection appropriate to your work environment is essential. Too much protection does not necessarily guarantee optimal safety.
For example, it is vital that workers can communicate and hear alarms despite their hearing protection.
Some earmuffs allow communication via built-in microphones to ensure clear and accurate communication.