-
Hearing Conservation, Not Compensation
(Summary of Safety Breakfast Meeting held Wednesday, June 10, 1998)
HIGH NOISE LEVELS IN WORKPLACE MUST BE ADDRESSED
Question: Which sound has greater potential to damage your hearing -
a baby's cry or a jackhammer? If you answered the former, a baby's cry,
you were right, according to information provided by a representative of
the Center for Hearing and Health at the most recent Safety Breakfast
Meeting held at California State University, Fresno.
At 115 decibels, the sound of a baby's cry can begin to cause hearing
damage to a person next to the child after just 15 minutes, reported
Dorie Watkins, an industrial audiologist for the Center for Hearing
Health. The jackhammer doesn't quite measure up, measuring
"only" 105 decibels, she noted; but that level of sound also
can cause damage to the inner ear after one hour, according to medical
and science standards.
Why the concern about sound and hearing at a safety breakfast
meeting? Because if you are an employer you have a vested interest in
the inner ears of your employees, according to regulations maintained
and enforced by California's Occupational Safety and Health
Administration (Cal-OSHA). Cal-OSHA regulations require that industrial
employers administer a continuing, effective hearing conservation
program whenever workplace noise levels exceed those deemed tolerable by
OSHA-adopted standards.
Agriculture, along with a few other "field" industries, is
exempt from most of the OSHA regulations requiring administration of a
hearing conservation program. However, it is not exempt from the
requirement to provide personal protective equipment when noise exceeds
hearing safety levels.
HOW HEARING DAMAGE OCCURS
Hearing damage can occur inside the inner ear as a result of
excessively loud noise, Watkins explained. The inner ear, about the size
of a pencil eraser, contains special fluid and hair cells that transfer
sound information to the brain. "Hearing" occurs when sound
waves first enter the outer ear canal and vibrate the ear drum. The
middle ear bones transfer the sound waves to a small pocket of fluid in
the inner ear. The waves in the fluid move the hair cells, which send
the signals our brain recognizes and interprets as sound.
The hair cells can be damaged when exposed to excessive vibrations
over a period of time, Watkins said. The louder the sound, the less time
it takes to damage the cells. According to the Sight & Hearing
Association, hearing damage can occur if a a person is exposed to
sustained sound levels of 90 decibels or more for eight hours.
NOISES THAT HURT
Listed below is a series of common noises and the decibel sound
levels they produce. A decibel is a unit for measuring sound. 0 decibels
is considered the faintest sound a human ear can detect. A
"whisper" is typically measured at 30 decibels. Following each
decibel level is the amount of time the Sight & Hearing Association
has determined the human inner ear can tolerate the sound before damage
begins to occur.
