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Prolonged exposure to hazardous noise can have harmful effects on worker health. Monitor the hearing health status of the noise-exposed workers to identify changes then take action to prevent further damage.
How do we know if noise is affecting the hearing of our workers?
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An audiometric testing program checks the hearing thresholds of workers and tracks them over time. The objective is to detect changes or shifts in hearing that may signal the beginning stages of noise-induced hearing loss (NIHL). Identifying the signs and symptoms early enough, allows employers to intervene before the symptoms get worse. Therefore, part of the audiometric testing program is to ensure that effective follow-up actions are taken.
Audiometric monitoring programs depend on checking hearing thresholds in a consistent, standardised manner, using trained and competent personnel. The test room should be quiet enough to minimise distractions for valid thresholds to be obtained. A baseline hearing check (audiogram) done before the worker’s first exposure to hazardous noise is then compared to future, routine hearing checks. Typically done annually, these results help to identify problems, such as hearing threshold shifts.
Audiometric test programs can be offered in a variety of ways, including in-house testing, mobile service providers, or at a health clinic. They may be performed by an audiologist or physician, but are most commonly done by audiometric technicians or occupational hearing conservationists with specialty training. Any “problem audiograms” must be reviewed by an audiologist or physician to help determine follow-up actions. For example, in some cases, medical follow-up is necessary. If a permanent hearing loss occurs, a professional can help determine whether it is related to noise on the job.
The audiometric results can be used on an individual basis to teach workers about their own hearing health status. Also, the whole audiometric database can be analysed to identify trends and develop appropriate intervention plans. The results of the hearing checks should trigger follow-up actions.Refer to AS/NZS 1269.4 "Occupational noise management - Auditory Assessment" for more specific details.
Key Takeaways
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- Routine hearing checks can help detect early symptoms of over-exposure to hazardous noise.
- Effective follow-up for workers with hearing shifts can help prevent permanent noise-induced hearing loss.
- Quality audiometric testing programs rely on consistent procedures, standardized practices, and competent personnel.
- Careful review of hearing test results help determine what follow-up actions are needed and if workplace noise is a factor.
- The audiometric database is a snapshot of the hearing health of the noise-exposed workforce and can be used to identify trends and develop intervention plans.
Purposes of Audiometric Testing
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- Checking hearing, through an on-going monitoring program, is the health surveillance part of the hearing loss prevention program (HLPP). When workers are allowed to be in hazardous noise, they should be checked routinely. The purpose of the hearing check is to identify small changes in hearing which may be a symptom of being over-exposed to noise. Workers who show no changes in hearing, in spite of working in hazardous noise, are assumed to be well-protected. However, those who show hearing threshold shifts, need an intervention plan.
- Hearing testing can also be done in order to qualify (or disqualify) a worker from a particular job, if that job has written criteria for hearing. For example, in order to be licensed, an airplane pilot or commercial driver must have good enough hearing to meet the requirements.
- Hearing evaluations can also be performed to determine the cause of the hearing loss for purposes of determining if a hearing loss is work-related.
Getting Started With Audiometric Testing
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Step 1. Identify who is required to have a hearing test
All workers who are noise-exposed at or above the action level (85 dBA TWA), should be included in an audiometric testing program. This includes workers who are noise-exposed every day as well as those who are exposed only one day per year. Employers may choose to expand the program to include other workers; however, it is helpful to specify who is required and who is optional before the testing cycle starts. Look for noise exposure information in the noise survey records/reports. Noise surveys typically help to identify which areas, jobs, and/or individuals, are at or above the action level.
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Step 2. Choose how to deliver the testing program
The Safe Work Australia Code of Practice "Managing noise and preventing hearing loss at work" indicates workers regularly using hearing protectors should undergo audiometric testing - initially upon commencing work and then at least every two years. Knowing how many workers will need to be tested will help to determine the best method for delivering the hearing tests. Many factors, such as quality, employee time away from the job, flexibility, space, personnel, access to records, and total cost of the program, are all typically considered. The goal is to establish a robust long-term program that is stable and continuous. Keep in mind that the cost of poor quality can be high, not only in dollars, but also in wasted time and effort, worker health, productivity, and morale, and employer liability.
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Step 3. Schedule and conduct the testing
Scheduling the tests is somewhat dependent on the method chosen for delivering them. For example, the testing can be spread throughout the year or done within the same week or month every 2 years. Some considerations for scheduling are: the time or season of the year, the start and end times of the work shift, and the availability of workers to be away from job tasks. Employees who need a baseline test should avoid workplace noise exposure for at least 16 hours, or wear hearing protection, before the test.
Conducting hearing checks also gives other opportunities to interact with workers. Extra training can be provided and the condition and fit of the hearing protection can be checked.
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Step 4. Send all “problem audiograms” to physician or audiologist for review
Once the tests are completed, there can be follow-up work to be done. “Problem audiograms” should be reviewed by a physician or audiologist. This means that workers who may have a significant change in hearing, signs of a hearing loss, or questionable test results, should have their records reviewed by a professional to determine if and what additional intervention is needed.
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Step 5. Complete any follow-up actions needed.
There are many types of follow-up actions that may be necessary based on the audiometric test results and the medical history information given by the worker. Some types of follow-up are required and others are optional. It is typically helpful to work with a physician or audiologist to outline follow-up and intervention needs. Some examples of follow-up actions are: retesting and retraining workers who have experienced a standard threshold shift (STS), retesting a worker who had an incomplete or invalid test, referring workers with signs of medical conditions to a physician or audiologist, fit-testing of hearing protection, investigating workplace hazards, and determining work-related hearing loss.
Requirements for audiometric testing are detailed in AS/NZS 1269.4 "Occupational noise management - Auditory Assessment". The following is a brief summary of the requirements; the regulation itself should be consulted for actual language and/or use. Note that State Regulations or Codes of Practice may have additional requirements.
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Who must have an audiometric test? Who can perform the test?
Who must have an audiometric test?
All employees who are required to frequestly use personal hearing protectors as a control measure for noise that exceeds the action level (85 dBA TWA) should be in an audiometric monitoring program.
Who can perform the audiometric test?
Testing can be completed by a competent person - competent as described in AS/NZS 1269.4 Appendix E.
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What are key requirements of the testing program?
- Audiometric testing must be available at no cost to the employees.
- Audiometers must meet specified equipment and calibration requirements.
- Testing of equipment should be conducted as specified in AS/NZS1269.4 Relevant audiometric test procedures are described in Section 8 of AS/NZS1269.4
- Pure tone air-conducted thresholds are obtained for a minimum of the following frequencies: 500, 1000, 1500, 2000, 3000, 4000, 6000 and 8000 Hz. Each ear is tested separately.
- Reference audiometry tests must be preceded by 16 hours away from workplace noise OR hearing protection must be used.
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When are audiometric tests conducted?
Baseline tests
Done within the first 6 months of noise exposure at or above 85 dBA TWA unless a mobile test van is used. In that case up to 12 months is allowed, however, hearing protection must be used if the test is done after 6 months.
There must be a 14-hour period of no workplace noise exposure before the baseline test. Hearing protection is allowed to be used as a substitute for the 14 hour noise free period.
Annual tests must be completed every 12 months or sooner and may be conducted at any time during the work shift.
Retest: if a worker shows STS on the annual test when compared to the baseline, a retest may be done within 30 days of the annual test. The retest is optional.
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Where are the tests conducted?
The background noise where the hearing test is conducted must meet specific noise levels - see AS/NZS1269.4
Beyond the Basics
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Testing Considerations
- Ensure the audiometric technician is competent,
- Include 8000 Hz in the test frequencies to allow better identification of possible noise-induced hearing loss,
- Minimise distracting background noise in the test room by applying lower maximum octave band limits, similar to a clinical environment,
- Consider use of insert earphones to minimise background noise, improve hygiene, and reduce masking needs,
- Do not allow the use of hearing protection as a substitute for the 14-hour noise-free interval before the baseline test,
- Schedule the annual audiograms during the work shift to better identify changes in hearing thresholds due to on-the-job noise exposure,
- Offer an “exit audiogram” for workers who are either leaving the HLPP or terminating employment.
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Intervention Strategies
- Emphasise early identification of NIHL symptoms: do not apply age-corrections when identifying STS, OR use a different metric,
- Expand the intervention protocol by enhancing the worker education,
- Verify hearing protection attenuation through hearing protection fit-testing,
- Investigate and implement noise control options.
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What triggers mandatory hearing tests?
Employee noise exposures at 85 dBA TWA and above and are using hearing protection regulalry.
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When does the baseline audiogram have to be done?
As soon as possible after commencment of employment (AS/NZS1269.4 and Code of Practice "Management of Noise in the workplace" October 2002.)
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How often are hearing tests done?
Annually
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Can the employee work in noise before the baseline test?
Yes, but only if hearing protection is worn during the noise exposure.
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Can the employee work in noise before the annual test?
Yes.
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Can the employee be sent to a local clinic to complete the hearing test?
Yes, assuming that the clinic is competent and there is no cost to the worker by doing so.
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I have a worker with a hearing aid. Can a test be done?
Yes, however the hearing test must be done without the hearing aid. If necessary, the worker could be tested by an audiologist.
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I have a worker who has severe tinnitus. Can I still test hearing?
Yes, however sometimes tinnitus (ringing in the ears) can make it more difficult to obtain valid thresholds. If the results are inconsistent, the worker may be having trouble distinguishing the test tone from the ringing in his ears. One option is to refer the worker to an audiologist to obtain a valid test.
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My employees don’t speak English. How can they be tested?
One option is to use an interpreter to explain the purpose of the test and instructions. Some audiometers have an additional feature to instruct the worker through the earphones, in the preferred language.
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Is it required to look in the ears with an otoscope before the test?
A visual inspection of the ear canal is not required by regulation however it can give helpful information about the health of the ear and whether or not a test should be conducted.
Resources for Audiometric Testing
Refer to documents:
- Control Guide: Management of Noise at Work
- ACOP: Management of Noise in the Workplace. Section
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IMPORTANT NOTE: This information is based on selected current national requirements. Other State or local requirements may be different. Always consult User Instructions and follow local laws and regulations. This website contains an overview of general information and should not be relied upon to make specific decisions. Reading this information does not certify proficiency in safety and health. Information is current as of the date of publication, and requirements can change in the future. This information should not be relied upon in isolation, as the content is often accompanied by additional and/or clarifying information. All applicable laws and regulations must be followed.
