Noise Resources

If NIHL could be corrected the way glasses and contact lenses correct poor eyesight, then encroaching deafness wouldn’t seem as dire. Unfortunately, NIHL is a cumulative disorder, usually taking many years to develop. Over time, sufferers of NIHL find they lose the ability to hear both softer sounds and higher frequencies.

Extended exposure to noise may damage the hair cells in the inner ear. At first, this damage is temporary, particularly if exposure is no more extensive than a single rock concert or a day on a motorboat. Many people have walked out of a concert arena with “filled” ears, making it hard to hear for a few hours. Eventually, full hearing returns.

Over time, however, continuous exposure to excessive noise causes the hair cells to sustain so much damage that the “hair” bundles break off and cannot sense sound, and they may also die. Hearing aids can’t restore something that is broken off or dead. Despite continual improvement in hearing aids, both in their effectiveness and size reduction, and the fact they may improve amplification, wearers cannot regain perfect (or near perfect) hearing. Furthermore, hearing aids in higher noise environments could accelerate NIHL by adding to the daily dose the person receives because of their amplification. Therefore, hearing aids should only be used in quieter areas.

Imagine listening to your kitchen garbage disposer (approximately 80 dB) for eight hours at a time. You may throw your hands over your ears at the mere thought. Unfortunately, for millions of American workers, exposure to dangerous levels of noise (85 dB or above) is a daily fact of life.

Over the last 20 years, government agencies have consistently identified NIHL as one of the top concerns of workers. Some occupational health and safety experts even call noise the most pervasive hazard in the workplace. Yet occupational hearing loss is a particularly insidious hazard because it sneaks up on the worker. Because it doesn’t make the headlines like an industrial accident or sudden on-the-job injury might, noise is a stealth hazard that attracts little attention from the public.

The problem of noise in the workplace isn’t new. For example, the problem of “blacksmith’s deafness,” from the continual clanging of metal on metal, dates back hundreds of years. But since World War II—when noise-induced hearing loss began attracting serious attention as soldiers returned from battle with hearing problems—there’s little question workplaces have gotten louder.

From airports to construction sites, street repairs to landscaping, even large restaurants—workers face a continual barrage of noise. Belt sanders (93 dB), bulldozers (105 dB), chainsaws (110 dB), and pneumatic drills (119 dB) are just some of the offenders. Even people in seemingly glamorous jobs suffer from noise exposure. Probably the most famous case of NIHL is rock musician Pete Townshend, lead guitarist of the band The Who, who claims to be mostly deaf from exposure to loud music at the band’s concerts and rehearsals.

For some people, the idea of being able to shut out a difficult boss or cranky customer must seem appealing, but that is neither realistic nor safe. In fact, when it comes to hearing problems on the job, that is a downright unsound idea.

Hearing is vital to many aspects of safety and performance. Other than communicating with one another, workers must be able to hear announcements and pages over a public address system, as well as fire and other evacuation alarms or vehicle back-up signals. Equipment operators rely on subtle changes in sound to gauge whether their equipment is running correctly. Many equipment operators cite the need to “hear” their machines as a reason for not wearing hearing protection; they actually will be able to hear the machines better with hearing protection than without, but will need time (a week or two) to adjust to the differences in their perception. The lower frequency noise of a grinding machine transmit well through hearing protection, much like the lower frequency of drums from music transmits well through a closed car.

Good hearing helps workers avoid accidents and reduces the likelihood of serious injury. Studies show that workers in high-noise environments typically lose more time from accidents and are less productive than those exposed to lower noise levels. In addition, evidence shows that continuous high levels of noise cause worker stress, fatigue, and post-work irritability. In some studies, noise has even been linked to increased blood pressure.

Although workers in any field can be exposed to high levels of noise, certain industries have a greater risk. According to the National Institute for Occupational Safety and Health (NIOSH), industries such as mining, agriculture, construction, manufacturing, utilities, transportation and the military run the highest risk of NIHL. Although it is well known that rock musicians create massive waves of sound, even classical musicians—particularly those in orchestras—also experience high decibel levels. (Think row upon row of violins, trumpets, and percussion.)

The best way to prevent hearing loss is by avoiding excessive noise exposure in the first place. Fortunately, although NIHL is still common, it is completely preventable if companies establish effective hearing conservation programs. The Occupational Safety and Health Administration (OSHA) promotes federal noise- related guidelines that workplaces must follow, although some states also regulate workplace noise.

The first line of defense against occupational noise is to diminish loud sounds at their source, wherever possible. Such methods are called engineering controls and involve measures such as installing “silencers” (mufflers and baffles, for example) on equipment. Silencers work by absorbing sound—the muffler on your car is a good example. Acoustic barriers (such as specially constructed walls) can dampen sound from nearby machinery and are another excellent way to guard hearing. There is a national “Buy Quiet” movement to try to get companies and the military to buy quieter machinery, and to specify the sound output acceptable in the procurement order process. Here is what the U.S. Navy has to say about their “Buy Quiet” initiatives:

Purchase Quiet Equipment

The U.S. Navy has a "Buy Quiet" policy for equipment aboard ship. Selecting quiet equipment, systems, tools, etc. at the earliest stages of acquisition is the best way to reduce noise at the source.

The "Buy Quiet" approach requires designers and engineers to obtain noise emission data before purchasing to choose the quietest available and affordable equipment. Noise emission values obtained from various suppliers can be compared with each other, and can be used for prediction of the noise levels in the area where equipment is to be placed.

Even though quieter equipment generally can be more expensive to purchase, the equipment is usually better built and has high efficiency. It also can require a simpler noise control installation. These features help to reduce the operating and maintenance costs of the equipment, reducing its total life cycle cost.

If the equipment cannot incorporate a silencer or acoustic barrier, or other engineering controls prove impractical, or if the worker cannot be moved away from the noise source entirely, the last line of defense to dampen noise is by blocking the noise with hearing protection devices (HPDs), such as earplugs or earmuffs. The number, variety, and effectiveness of HPDs have improved steadily since World War II. In general, HPDs do not eliminate all sound—which would be both impractical and potentially dangerous—but, if properly used, they reduce noise to safer levels.

Unfortunately, HPDs have one big drawback: no matter how effective the device, it only works if the wearer fits it correctly and uses it when necessary. This is true of hearing conservation programs in general. They rely on the cooperation and motivation of workers and management alike to make them effective. If their only purpose is to avoid an OSHA citation, achieving the goal of protecting workers’ precious hearing may be compromised. To overcome some of these problems, several HPD manufacturers provide methods of “fit testing” hearing protection devices. These are becoming valuable for ensuring that HPDs work well on the individual.

Both employers and workers must be educated about the importance of good hearing and avoiding NIHL. While this may seem self-evident, many people hold common misconceptions about hearing loss. Young people often view it as an older person’s concern, while others mistakenly believe hearing aids will fully restore any loss. Management, too, must commit to the program, whether for humanitarian or business reasons. Every successful work-related hearing conservation program requires buy-in from every level of the workforce.

Anyone who has heard a leaf blower while trying to sleep in on Saturday morning is well aware noise isn’t a problem only in the workplace. Like on-the-job noise, people have complained of the increasing din in their communities for more than 100 years. As society grows more mechanized, the sounds get louder.

For years, much of the focus was on city noise: ventilation systems, commuter trains, buses. Unfortunately, noise now seems all-pervasive. Even suburbanites and rural dwellers must endure jets flying overhead, heavy traffic, or nearby industrial plants.

In the community, noise levels receive greater attention at night, particularly if they disturb sleep. Also, noise tolerance tends to increase or decrease based on perception. A homeowner in the country usually expects quieter nights (and days, for that matter). But while a city dweller may expect more environmental noise, everyone has the right to retain his or her hearing.

Not all environmental noise emanates from the workplace. In fact, recreation can create a pretty big racket. Some of the loudest sources include: motorcycles (95-110 dB); sporting events (105 dB); fitness clubs (105 dB); stereo boom boxes (100 dB); snowmobiles (100 dB); dance clubs (110 dB); live popular music concerts (120 dB); and firecrackers (150 dB).

The difference between recreational noise and industrial or commercial noise, however, is that individuals have more control over their own behavior. However, adding sound to drown out sound only results in more sound, so don't fight fire with fire when dealing with noise problems in your neighborhood. Blocking road noise with pumped-up music on your headphones could cause more damage than the original problem.

There is currently no single national community noise statute. The Noise Control Act of 1972, passed by Congress, places responsibility for regulating community noise in the hands of the states and cities. At that time, the Environmental Protection Agency established the Office of Noise Abatement and Control (ONAC). Although ONAC did not have enforcement capability, it provided extensive information about noise to the public and provided advice to states and cities. Unfortunately, ONAC lost most of its funding several years ago, and efforts to restore it to its former strength so far have been unsuccessful.

This grab bag of noise legislation has resulted in different regions of the country having different laws—or no noise laws at all. These variances are particularly challenging to companies with multiple locations, not to mention to the officials who must judge these companies’ compliance with regulations. At this time, only about 13 states have any form of noise regulations, but enforcement is often spotty.

In the nearly five decades since the Noise Control Act of 1972, however, increasing media awareness about noise—and the increasing noise itself—has resulted in the creation of numerous community-based anti-noise groups. These groups, whether acting alone or representing an alliance of grassroots organizations with state and national support, have proven effective. In California alone, more than 40 communities have successfully banned or severely restricted the use of gas-powered leaf blowers; more than 300 cities and towns across the country have done the same. Nonprofit organizations such as the Noise Pollution Clearinghouse provide assistance to communities seeking to limit the noise in their neighborhoods.