Hearing Conservation Program Administration
Part 3: Audiometric Testing
Slide 2
One of the key elements of the Hearing Conservation Program is the audiometric testing
program in which employees who are exposed to high noise levels have their hearing
tested annually. Some of the questions that we will address in this section will be:
 Why is the testing necessary?
 What are we trying to accomplish?
 Who is the most appropriate person or persons to administer the test?
 Which employees should be in the audiometric testing program?
We will also look at the recordkeeping that’s involved, the methods used to schedule the
hearing test and ways to insure good quality in the audiometric program. However, we
won’t cover the specifics of how to conduct a hearing test. The process is not very
complicated and can be quickly learned, but needs hands-on practice and thus goes
beyond the scope of what is intended for this lecture on HCP administration.
Slide 3
The basic goal of audiometric testing as a part of a hearing conservation program is to
detect early hearing loss, beyond what would be expected from the normal aging process
in case it is caused by on the job exposure. Once the hearing deterioration is detected,
steps can be taken to avoid more loss. It’s an early warning system which looks for the
first signs of hearing loss before it becomes bad enough to cause impairment.
The audiometric testing program starts with the baseline audiogram which measures the
employee’s hearing ability before noise exposure begins, or shortly after it starts. Tests
are conducted annually while the noise exposure continues, and the annual tests are
compared to the baseline audiograms to see what changes there might be. This
comparison is usually corrected for normal aging loss and is done at the three sound
frequencies where hearing loss due to noise usually first appears (2000, 3000, and 4000
Hertz). By averaging over three frequencies, true changes are emphasized and not just
random fluctuation.
If there is enough change (10 dB or more) from the baseline audiogram to a later one (for
either ear), it would be called a standard threshold shift (STS). The whole point of the
procedure is to compare each of the annual tests to the pre-exposure baseline. One key
factor to remember in the testing is to maintain consistency so that you can always have
accurate comparisons. We’ll discuss this more in the quality control section of the
lesson.
Slide 4
After an STS has been identified, what actions need to be taken by the employer? The
first step is written notification of the employee within 21 days. The exact form of this
notification is not specified by OSHA, but it should make clear to the employee that an
abnormal or excessive amount of hearing loss has been identified, relate this loss to
exposure to noise (on and off the job) and emphasize the need for protection from noise.
The key point is to put the worker on notice that his or her health is being harmed and
that action is needed. It may also be necessary, if the worker is currently wearing hearing
protectors, to re-train or re-fit as necessary to improve the degree of protection. Of
course, if hearing protectors are not being used, then use needs to begin. We’re assuming
that the hearing loss would not have occurred if the hearing protection had been adequate.
If it is found at this point that the worker can’t successfully use earplugs (which some
people can’t), then earmuff use may be necessary.
The third action is to change to a new baseline audiogram for future comparisons, if the
STS seems to be persistent. The objective is to avoid identifying the same STS every
year, which could happen if no baseline change was made. By changing the baseline,
only new and additional hearing losses will be identified. In some cases if an STS occurs,
it also becomes a recordable occupational illness, according to OSHA regulations. [Of
course, some states may have different rules, but the regulations referred to here are 2007
federal OSHA requirements.] For the hearing loss to become recordable, it must meet all
STS requirements, including work-relatedness, and the thresholds in the ear where the
STS occurred must be greater than or equal to an average of 25 dB or more at 2, 3, and
4000 Hz.
Missing from the list of required actions is a mandate to send the worker for medical or
audiological evaluation. That not normally required, unless the medical supervisor of the
hearing conservation program requires seeing each person identified with an STS. The
only time that OSHA requires a medical referral within the hearing conservation program
is if there is a medical problem caused or aggravated by the use of hearing protectors.
Usually this would be some form of ear infection; if hearing protector use contributed to
this condition, then medical referral at the employer’s expense would be required.
Slide 5
One of the decisions that must be made in setting up an HCP is who will actually do the
audiometric testing, since there are several possibilities. One which is used by a great
many industries, particularly the larger ones, is a mobile testing service which will bring
to the worksite a van with anywhere from one to eight hearing booths. Some of these
mobile testing contractors provide full services, including noise monitoring, training,
recordkeeping, interpretation, etc. Because of their level of experience and the frequency
with which they perform this service they can quickly move people out in groups and
accomplish the task of hearing tests for many employees in a single day. The chief
difficulty with this method is a lack of flexibility. If employees are missed or require retesting it is often not economically feasible to have the van return for just a few tests.
However, testing a large number of people can be best accomplished using this method.
Another alternative utilized by many employers is in-house testing, in which a facility
employee is trained to perform the testing, using the necessary equipment on the site. If
available, the facility nurse is the logical person to do the testing, but the tester does not
have to be a medical professional. The best thing about in-house testing is the flexibility.
The tester and the equipment are available whenever needed so that you can get the job
done when needed. For example, when someone is first hired a hearing test can be done
right away rather than waiting for many months, or even a year; until the mobile service
returns.
Of course, in-house testing has both capital and operating costs. An audiometer is needed
which ranges from a few hundred to a few thousand dollars, depending on the degree of
automation and computerization. A specially-built quiet booth is also normally used,
although it’s not absolutely necessary but you must at least have a very quiet room if
you’re not going to do it that way. Having the booth helps to build credibility.
Another possibility would be to use a local medical clinic which may have the equipment
and the expertise to conduct the testing. Such clinics are available in many small
communities and may be a good choice for the employer who has only a few employees.
There be will some lost time due to traveling between the worksite and the clinic, but on
the other hand, the testing program will have good credibility because the employees will
be getting other medical services at the clinic rather than being tested by a technician who
doesn’t have the medical background. One warning with regard to local clinics is that
sometimes, not being specialists in occupational hearing conservation, they may not
know how to do things according to OSHA rules. They may do things in a medically
appropriate way, but possibly not be quite in accordance with OSHA.
Slide 6
Next, let’s consider who should be tested in the hearing conservation program. The
OSHA regulations state that any employee exposed to 85 dBA time weighted average
(TWA) or greater needs to be included in the hearing test program, but how often must
this exposure occur to trigger the test requirement? One rule of thumb that is often used
is that if the exposure at 85 dBA TWA occurs once per week or more often then the
employee should be in the hearing conservation program. There’s nothing to prevent an
employer from including employees under a more inclusive policy, however.
There are also standards that employers should be aware of from the American
Conference of Governmental Industrial Hygienists (ACGIH), the organization which
produces the Threshold Limit Values which are widely used for chemical exposure
assessment. The ACGIH noise standards are more inclusive than the OSHA regulation
and are based on more recent scientific studies of hearing loss. Generally speaking,
workers who have high noise exposure, but for only brief periods, may be exempt under
OSHA, but included under the ACGIH standard.
In general, it doesn’t hurt to have a more inclusive policy since it’s such a simple
program. The monetary costs are usually small and employees may perceive the testing
as a benefit, but on the other hand, employees may also perceive the testing as indicating
a significant risk of hearing loss and may later attribute hearing loss to their occupational
exposure, correctly or not. Some workers will lose their hearing at an accelerated rate,
due to completely non-occupationally related causes. If care is not taken, the employer
may have unjustified recordable occupational illnesses from hearing loss and potential
hearing loss claims.
Slide 7
One element of the audiometric testing program that has nothing to do with the actual
testing of hearing is the recording of hearing health history. This record will be used to
help in the medical determination of the cause of any hearing loss that may later occur. If
a person has substantial non-occupational noise exposure or a family history of hearing
loss or documented ear disease, then a record may be helpful to the employer for
avoidance of liability for occupational hearing loss.
There should be a form completed for each hearing test, and there are a number of forms
available. Some of the basic common questions would include current hearing problems
and activities such as noisy hobbies, power tool use, loud music exposure, and other
kinds of non-work related noise exposure. The employee should be asked what kind of
hearing protection is being used and how often. However, sometimes employees record
on their forms that they are not using their hearing protection and yet no action is taken,
showing that the employer was put on notice that the employee was not wearing his
hearing protectors. Consequently when that employee later suffers hearing loss liability is
more likely to be attributed to the employer.
Slide 8
Proper scheduling is an important part of getting good audiograms. For the baseline
audiogram, OSHA requires that in order to minimize the possibility of recording a
temporary threshold shift (TTS), the person should have at least 14 hours away from
workplace noise. The presumption is that employees will have recovered from at least
the temporary part of the hearing loss within 14 hours, regardless of the noise exposure.
As long as the worker is using good hearing protection to protect them from any
workplace noise exposure that they may get before the exam, any time of day for the
baseline test is acceptable.
Testing first thing in the morning often done for the baseline audiogram, but is only valid
if the employee did not have substantial noise exposure during the time immediately
proceeding coming to work. For example, a person riding on a motorcycle for an hourlong commute to work would probably have some TTS. Employees who start work at
some shift other than first thing in the morning may also have had considerable exposure
during the day or the evening proceeding their work. The first moment of work is not
always the best time for the baseline test. Individual situations need to be taken into
consideration in deciding the best time.
For the annual audiogram, according to OSHA, anytime is acceptable, without regard to
workplace noise exposure. This scheduling flexibility is conservative and protective of
the worker in that if he has temporary threshold shift, it will show up in comparison to the
baseline and will cause the person to appear as though they have more hearing loss that
they actually have. From the employer’s point of view, this possible inclusion of TTS is
not particularly desirable, but being able to do hearing tests anytime during the day is a
great convenience. If employees are exposed to substantial amounts of noise, they need
to be sure to wear their hearing protectors before the hearing test. If any temporary
threshold shift is picked up, that would not only show that the noise is excessive, but that
the hearing protectors are not effective.
Slide 9
Since the audiometric test is the actual proof of whether the hearing conservation
program is effective, it’s important that it be done accurately and consistently. Any
variation in the procedures ay show hearing loss which isn’t there, or it may cover up true
hearing loss. One important factor in consistency is the instructions given to the
employees before starting the hearing test. The way people are instructed to respond to
the sounds makes a difference. If you say, for example, “push the button when you hear
the tone,” some people may wait until they very clearly and definitely hear it, although in
actuality they should respond at the point where the sound is so faint that they just barely
perceive it. For most subjects, the instructions should be “push the button if you hear the
sound or think you hear the sound.” The instructions also need to be consistent from one
person to the next and from one year to the next.
Proper placement of the headphones over the ears is also important for consistency. The
person conducting the test, rather than the person being tested, should put them in place
to insure that the working part of the headphone, the diaphragm, is directly over the
eardrum. It’s also important to have good employee cooperation to get consistent results.
The interaction between the tester and the test subject needs to make sure that employees
understand the purpose of the hearing test. Workers should be reassured that the hearing
test is not one that they can pass or fail.
Also important for quality control is calibrated equipment. An annual comprehensive
instrument test is needed, but the audiometer should also be tested daily for accuracy and
sound distortion. Any problems that show up on the daily test call for a comprehensive
instrumentation evaluation. The daily checks are done by the audiometric technician, and
the annual evaluations are usually done by the supplier of the equipment. Those tests can
either be at the facility where the tests are done, or the audiometer and headphones can be
sent to the calibration lab.
Finally, there is a need for a quiet test environment. The OSHA regulations specify how
quiet it needs to be, but these rules are somewhat lax, so a test environment that is quieter
than OSHA requires is desirable. The employees being tested also will have more
confidence in the program, if they have a quieter environment. Measurement of the test
room background noise is customarily done annually, when the audiometer is calibrated.
Slide 10
The audiometric testing process generates lots of records: the actual test results, the
hearing history forms, the STS calculation, the notification, and others. The audiometric
records themselves are required by OSHA to be kept for the duration of the worker’s
employment, but a good practice is to keep them for the duration of employment plus
several more years. Many workers’ compensation programs allow for filing of claims
two years after discovery of illness or injury, so two years past the duration of
employment should be a minimum. Actually since the records may be maintained in a
compact form there’s no reason to ever destroy the records.
Any format is acceptable as long as it’s accessible later: on paper, microfilm, or
computerized. Employees and former employees have the right of access to these records
so they need to be maintained in a way that they are readily available to employees. On
the other hand, the employee’s privacy rights also need to be respected so Federal and
state rules regarding medical records need to be followed. Individuals who don’t have a
need to know should not be able to access hearing records. For example, a supervisor
would not usually need to know the detailed hearing status of employees under his
supervision. Only the HCP administrators and medical personnel should have a need for
access to the records.