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Hearing Conservation The
following summary briefly discusses the required components of the hearing conservation
program. |
| Monitoring |
The hearing conservation amendment requires employers to
monitor noise exposure levels in a manner that will accurately identify employees who are
exposed to noise at or above 85 decibels (dB) averaged over eight working
hours, called an 8-hour time- weighted average (TWA). The exposure measurement must
include all noise within an 80 dB to 130 dB range and must be taken during a typical work
situation. This requirement is performance oriented since it allows employers to choose
the monitoring method that best suits each individual situation.
Under this revised amendment, employees are entitled to observe monitoring procedures and
they must be notified of the results of the exposure monitoring of their workplace.
The method used to notify employees is left to the discretion of the employers.
Instruments used for monitoring employee exposures must be carefully checked or calibrated
to ensure that the measurements are accurate. Calibration procedures are unique to
specific instruments. Employers have the duty to assure that the measuring instruments
they are using are properly calibrated. They may find it useful to follow the
manufacturer's instructions to determine when and how extensively to calibrate. |
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Audiometric Testing |
Audiometric testing not only monitors the sharpness or acuity of an
employee's hearing over time, but also provides an opportunity for employers to educate
employees about their hearing and the need to protect it.
The important elements of an audiometric testing program include baseline audiograms,
annual audiograms, training, and follow-up procedures. Audiometric testing must be made
available to all employees who have average exposure levels over an 8-hour period of 85
dB. And the audiometric testing program follow-up should indicate whether hearing loss is
being prevented by the employer's hearing conservation program.
A professional audiologist (specialist dealing with individuals having impaired hearing),
an otolaryngologist (physician specializing in the diagnosis and treatment of disorders of
the ear, nose, and throat), or a physician must be responsible for the program. Both
professionals and trained technicians may conduct audiometric testing. The professional
does not have to be present when a qualified technician is conducting testing, however.
The professional responsibilities include overseeing the program and the work of the
technicians, reviewing problem audiograms, and determining whether referral is necessary.
There are two types of audiograms required in the hearing conservation program: baseline
and annual audiograms.
a. Baseline Audiograms
The baseline audiogram is the reference audiogram against which future audiograms are
compared. Baseline audiograms must be provided within 6 months of an employees's first
exposure at or above an 8-hour time weighted average, TWA, of 85 dB. Where employers are
using mobile test vans to obtain audiograms, baseline audiograms must be completed within
one year after an employee's first exposure to workplace noise at or above a TWA of 85 dB.
Where mobile vans are used and employers are allowed to delay baseline testing for
up to a year, after 6 months their employees exposed at or above 85
dB must be issued and fitted with hearing protectors to be worn until the baseline
audiogram is obtained.Baseline audiograms taken before the
effective date of this amendment are acceptable baselines in the program if the
professional supervisor determines that the audiogram is valid.
b. Annual Audiograms
The annual audiograms must be conducted within one year of the baseline. It
is important to test hearing on an annual basis in order to identify changes in hearing
ability so that protective follow-up measures can be initiated before hearing loss
progresses. Annual audiograms must be routinely compared to baseline audiograms to
determine whether the audiogram is accurate and to determine whether the employee has lost
hearing ability (that is, if a standard threshold shift (STS) has occurred). STS is
defined in the amendment as an average shift in either ear of 10 dB or more at 2000, 3000,
and 4000 Hz. An averaging method of determining STS was chosen because it diminishes the
number of persons falsely identified as having STS who are later shown not to have had a
change in hearing ability.
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Audiogram Evaluation |
If an STS is identified, employees must be fitted or refitted with
adequate hearing protectors, shown how to use them, and required to wear them. Employees
must be notified within 21 days from the time the determination is made that their
audiometric test results showed an STS. Some employees with an STS may need to be referred
for further testing if the professional determines that their test results are
questionable or if they have an ear problem of a medical nature which is thought to be
caused or aggravated by wearing hearing protectors. If the suspected medical problem is
not thought to be related to wearing protectors, employees must be informed that they
should see a physician. If subsequent audiometric tests show that the STS identified on a
previous audiogram is not persistent, employees whose exposure to noise is less than a TWA
of 90 dB may discontinue the wearing of hearing protectors. A subsequent audiogram may
be substituted for the original baseline audiogram if the professional supervising the
program determines that the employee's STS is persistent. This substitution will ensure
that the same shift is not repeatedly identified. The professional may also decide to
revise the baseline audiogram if an improvement in hearing has occurred. This will ensure
that the baseline reflects actual hearing thresholds to the extent possible.
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Hearing Protectors |
Hearing protectors must be available to all workers exposed to 8-hour
time-weighted average noise levels of 85 dB or above. This requirement will ensure that
employees have access to protectors before they experience a loss in hearing. Hearing
protectors must be worn by: 1) employees for any period exceeding 6 months from the time
they are first exposed to 8-hour average, e noise levels of 85 dB or above until they
receive their baseline audiograms in situations where baseline audiograms are delayed
because it is inconvenient for mobile test vans to visit the workplace more than once a
year; 2) employees who have incurred standard threshold shifts since these workers have
demonstrated that they are susceptible to noise; and 3) employees exposed over the
permissible exposure level, an 8-hour time-weighted average of 90 dB or above. Employees
should decide, with the help of a person who is trained in fitting hearing protectors,
which size and type protector is most suitable for their working environment. The
protector selected should be comfortable to wear and offer sufficient attenuation to
prevent hearing loss.
Hearing protectors must adequately reduce the severity of the noise level for each
employee's work environment. The employer must reevaluate the suitability of the
employee's present protector whenever there is a change in working conditions that may
cause the hearing protector being used to be inadequate. If workplace noise levels
increase, employees must be given more effective protectors. The protector must reduce
employee exposures to at least 90 dB and to 85 dB when a standard threshold shift has
already occurred in the worker's hearing. Employees must be shown how to use and care for
their protectors and must be supervised on the job to ensure that they continue to wear
them correctly.
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Training |
Employee training is very important. When workers understand the
reasons for the hearing conservation program's requirements and the need to protect their
hearing, they will be better motivated to participate actively in the program and to
cooperate by wearing their protectors and taking audiometric tests. Employees exposed to
TWA's of 85 dB and above must be trained at least annually in the effects of noise, the
purpose, advantages, and disadvantages of various types of hearing protectors; the
selection, fitting and care of protectors; and the purpose and procedures of audiometric
testing. The training program may be structured in any format, different parts being
conducted by different individuals and at different times as long as the required topics
are covered. |
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Recordkeeping |
Noise exposure measurement records must be kept for 2 years. Records of
audiometric test results must be maintained for the duration of employment of the affected
employee. Audiometric test records must include the name and job classification of the
employee, the date, the examiner's name, the date of acoustic or exhaustive calibration,
measurements of the background sound pressure levels in audiometric test rooms, and the
employee's most recent noise exposure measurement. |
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