When your teen-age child or friend is ignoring you, it may not be a sullen pout. He or she may not hear you.
Thanks to lawn mowers, chain saws, firecrackers, target-shooting and high-decibel stereos, young people increasingly are destroying their inner-ear cells that process sound and are slowly but surely going deaf.
"A shocking fact is that noise-induced hearing loss can begin between 10 and 20 years of age, much earlier than originally thought," Dr. James B. Snow Jr., director of the National Institute on Deafness, told Congress yesterday.
Such hearing loss -- which can even affect toddlers -- is irreversible, he said. But it is almost always preventable.
Nearly 20 years ago, Congress empowered the Environmental Protection Agency to set ambient noise standards and enforce them. The EPA never got around to doing it, and in 1982 simply shut down its noise abatement bureau as part of the government deregulation frenzy then in vogue.
In the last 10 years, hearing experts told the House Select Committee on Children, Youth and Families, the threat of hearing loss has spread to growing numbers of young people.
Of the 28 million Americans who suffer from hearing loss, said committee chairwoman Patricia Schroeder, D-Colo., 10 million are victims of exposure to loud sounds.
Ms. Schroeder said about 21 million personal stereos, ranging from Sony's Walkman to boom-boxes and big-sound car systems, were sold in the United States last year -- mostly to young people.
"Most kids don't realize that even listening at half the full volume may hurt their ears," she said, citing studies showing that live and amplified music was the prime cause of hearing loss in one of eight adolescents and young adults.
Expert witnesses said anything louder than an alarm clock or hair dryer -- which generally register about 85 decibels -- can damage hearing. Measured sound at rock concerts and on personal-stereo ear sets often reaches 125 decibels. Each five-point rise in decibels represents a doubling of the loudness.
Mr. Snow said, however, that loud music is not the only cause, or even the principal source, of premature deafness.
"The teen-ager who is working on his or her car, using a lawn mower or leaf blower, working with a sander or an electric saw in shop class" is subject to hearing damage, he said. "Gunfire is an important cause of hearing loss in adolescents."