Close your eyes, open your ears and, just for a moment, listen.
Chances are, what you hear are the sounds of an internal combustion society - computer squeals, amplified rock music, motorcycles, snowmobiles, food processors, vacuum cleaners, planes, trains and automobiles that need new mufflers.Our ears are exposed to a world that is getting louder. The luxury and convenience of technology and industry bring with them the kind of noise that over time can damage hearing.
Now some people entering their 40s and 50s are paying the price. Not only does the roar of modern life often blanket the sound of falling rain or the first robin's chirp of spring, but thanks to years of noise exposure, more and more of us may never fully hear those sounds again.
The same may hold true for the next generation to reach midlife. There are some indications that hearing loss, most often an affliction of those 50 and older, is occurring more frequently at a younger age.
"We are living inside an explosion," says Gordon Hempton, who calls himself the "Sound Tracker." He travels the world from his home in Washington state to record the vanishing sounds of nature. "It is literally a bomb going off, a petroleum bomb. As fossil fuel consumption doubles, we have doubled the noise produced in our environment."
About 28 million Americans have hearing loss - one-third of them because of long-term exposure to loud noises. Any sound level that is uncomfortable, generally 85 to 90 decibels, can damage hearing over time. And the damage is irreversible.
"It can occur without pain or notice," says Dr. David Buran, an ear specialist. "It is a national problem that we haven't recognized. We've accepted it."
Many lose hearing because of noise in the workplace. Engines, machine shops, textile mills, metal works, foundries and dozens of other industries can be hazardous to unprotected ears.
However, the U.S. Occupational Safety and Health Administration, has succeeded in establishing legal standards to prevent dangerous noise levels in most workplaces.
Generally, OSHA regulations require employers to supply ear protection if workers are exposed to noise levels of at least 85 decibels - the sound level of a loud engine - for more than eight hours a day.
Dixon Ward, a retired physicist at the University of Minnesota and an expert on noise-induced hearing loss, said some studies suggest job-related hearing loss is declining, thanks to the establishment of ear protection standards.
But hearing loss from environmental and recreational noise - the sounds that we often inflict on ourselves - is not declining.
Awareness of the damage loud sounds can do is growing. Many music clubs now hand out ear plugs to patrons, and foam ear plugs are becoming ubiquitous at drug store counters.
On April 24, several organizations are planning the first International Noise Awareness Day, which optimistically calls for a universal 60 seconds of total silence from 1:15 to 1:16 p.m. ET.
Hearing often fades when the microscopic hairs inside the inner ear are worn down, hampering their ability to transmit sound vibrations to the brain.
Age itself brings on some hearing loss. But some believe that the hearing loss that comes with age is at least partially noise-induced.
Studies raise concerns about what's happening to the hearing of 20-year-olds in industrialized countries - especially those who spent their adolescence listening to loud music in concerts and clubs and from boomboxes and personal stereos. Some research shows that hearing loss is being detected in surprising numbers of young adults.
One study by the University of Tennessee showed that 61 percent of a group of college freshmen had a detectable hearing loss, according to Nancy Nadler, director for the League of the Hard of Hearing in New York, an advocacy group.
But the scientific and medical data on the impact of environmental noise are murky. It's often impossible to determine what caused the hearing loss in someone who, for example, worked in a machine shop, practiced shooting at a rifle range and listened to the rock group Pearl Jam at full volume.
The cumulative effect, however, is the same.
Duane Halter, of Andover, Minn., spent his childhood around the racket of tractors and combines on his parents' farm in southern Minnesota. He suffered from rheumatic fever as an infant and worked his way through college playing saxophone and clarinet in any band - from rock to polka - that would pay him.
His wife is convinced that he has hearing loss. And as he looks his 50th birthday in the eye, he has finally come to accept the fact that he probably does.
"There are certain things I can't hear," he says, such as the TV and stereo when there is background noise.
More frustrating, he said, are the occasions when he can't hear what clients and colleagues are saying to him. "I keep having to say `What did you say?' `Can you repeat that?' "
Halter's neighbor, Robert Ryther, 59, traces his hearing loss to years working with the noisy equipment at Northwestern Bell. For 20 years, he worked in a room filled with telephone switches, which emitted a lot of high-frequency noise, then with noisy testing equipment and finally in a computer room full of loud fans.
It was only after he retired in 1986 and went to college to study French and art history that he became aware of a problem. During an art history exam, he identified an artist as Andre Drapeau. He got the answer wrong because he misheard the professor.
The correct name was Antoine Watteau.
One summer a few years after he retired, he volunteered as a guide at the University of Minnesota Landscape Arboretum, and during a training session on bog plants, a naturalist became excited about finding a plant he thought she called "wide leaf."
"On the way home, I was thinking, `That's a strange name,' " Ryther says. "And she said it tasted like onion. Then it hit me that what she really said was `wild leek.' Then I decided to do something because I was missing out on a lot of stuff."
Ryther now wears a hearing aid, and it helps. But hearing aids only amplify sounds that his ears can detect. He has forever lost the ability to hear clearly the high-pitched sounds in music and the voices of women and children.
"Just stuff your ears with cotton," he says. "That's what it's like."
There was a time when someone like Ryther might have accepted his hearing loss as part of growing old. But Elliot Berger, research director for the Cabot Corp., an Indianapolis maker of ear plugs, points out that awareness is growing with longevity.
Longer lifespans make it "more important to preserve those sensory systems," he says. "If you will be alive at 80, you might want to hear something."
Distributed by Scripps Howard News Service.