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Course 751 - Hearing Conservation Program Management

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Hearing Conservation:
Required Monitoring

Introduction

The hearing conservation program requires employers to monitor noise exposure levels in a way that accurately identifies employees exposed to noise at or above 85 decibels (dB) averaged over 8 working hours, or an 8-hour time-weighted average (TWA).

Employers must monitor all employees whose noise exposure is equivalent to or greater than a noise exposure received in 8 hours where the noise level is constantly 85 dB.

The exposure measurement must include all continuous, intermittent, and impulsive noise within an 80 dB to 130 dB range and must be taken during a typical work situation.

This requirement is performance-oriented because it allows employers to choose the monitoring method that best suits each individual situation.

When must the employer repeat monitoring?

Employers must repeat monitoring whenever changes in production, process, or controls increase noise exposure. These changes may mean that more employees need to be included in the program or that their hearing protectors may no longer provide adequate protection.

What is audiometric testing?

An audiometric test.
An audiometric test.

Audiometric testing monitors an employee’s hearing over time. It also provides an opportunity for employers to educate employees about their hearing and the need to protect it. The employer must establish and maintain an audiometric testing program.

The important elements of the program include:

  • baseline audiograms
  • annual audiograms
  • training, and
  • follow-up procedures

Employers must make audiometric testing available at no cost to all employees who are exposed to an action level of 85 dB or above, measured as an 8-hour TWA. The audiometric testing program follow up should indicate whether the employer’s hearing conservation program is preventing hearing loss.

A licensed or certified audiologist, otolaryngologist, or other physician must be responsible for the program. Both professionals and trained technicians may conduct audiometric testing. The professional in charge of the program does not have to be present when a qualified technician conducts tests. The professional’s responsibilities include:

  • overseeing the program and the work of the technicians
  • reviewing problem audiograms, and
  • determining whether referral is necessary.

The employee needs a referral for further testing when test results are questionable or when related medical problems are suspected. If additional testing is necessary or if the employer suspects a medical pathology of the ear that is caused or aggravated by wearing hearing protectors, the employer must refer the employee for a clinical audiological evaluation. There are two types of audiograms required in the hearing conservation program: baseline and annual audiograms.

What is a baseline audiogram?

The baseline audiogram is the reference audiogram against which future audiograms are compared. Employers must provide baseline audiograms within 6 months of an employee’s first exposure at or above an 8-hour TWA of 85 dB. An exception is allowed when the employer uses a mobile test van for audiograms. In these instances, baseline audiograms must be completed within 1 year after an employee’s first exposure to workplace noise at or above a TWA of 85 dB. Employees, however, must be fitted with, issued, and required to wear hearing protectors whenever they are exposed to noise levels above a TWA of 85 dB for any period exceeding 6 months after their first exposure until the baseline audiogram is conducted. Employees should not be exposed to workplace noise for 14 hours before the baseline test or wear hearing protectors during this time period.

What are annual audiograms?

Employers must provide annual audiograms within 1 year of the baseline. It is important to test workers’ hearing annually to identify deterioration in their hearing ability as early as possible. This enables employers to initiate protective follow-up measures before hearing loss progresses.

Employers must compare annual audiograms to baseline audiograms to determine whether the audiogram is valid and whether the employee has lost hearing ability or experienced a standard threshold shift (STS). An STS is an average shift in either ear of 10 dB or more at 2,000, 3,000, and 4,000 hertz.

What is an employer required to do following an audiogram evaluation?

Show them how to use their hearing protection.
Employers must show the employee how to use their hearing protection if they are showing an STS with adequate hearing protectors.

The employer must fit or refit any employee showing an STS with adequate hearing protectors, show the employee how to use them, and require the employee to wear them. Employers must notify employees within 21 days after the determination that their audiometric test results show an STS.

Some employees with an STS may need further testing if the professional determines that their test results are questionable or if they have an ear problem thought to be caused or aggravated by wearing hearing protectors. If the suspected medical problem is not thought to be related to wearing hearing protection, the employer must advise the employee to 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 stop wearing hearing protectors.

The employer may substitute an annual audiogram for the original baseline audiogram if the professional supervising the audiometric program determines that the employee’s STS is persistent. The employer must retain the original baseline audiogram, however, for the length of the employee’s employment. This substitution will ensure that the same shift is not repeatedly identified. The professional also may decide to revise the baseline audiogram if the employee’s hearing improves. This will ensure that the baseline reflects actual hearing thresholds to the extent possible.

When should an employer perform an audiogram?

For maximum protection of the employees (and for that matter, the company), audiograms should be performed:

  • during pre-employment;
  • prior to initial assignment in a hearing hazardous work area;
  • annually as long as the employee is assigned to a noisy job;
  • at the time of reassignment out of a hearing hazardous job; and
  • at the termination of employment.

In addition, it is suggested that employees who are not exposed be given periodic audiograms as part of the company's health care program. The audiograms of these employees can be compared to those of the exposed employees whenever the overall effectiveness of the hearing conservation program is evaluated. In an optimally effective program, the two employee groups will show essentially the same amount of audiometric change.

When are employees required to wear hearing protectors?

Hearing protection symbol
Common symbol for the requirement of hearing protection to be worn in a work area.

Employees must wear hearing protectors:

  • for any period exceeding 6 months from the time they are first exposed to 8-hour TWA noise levels of 85 dB or above, until they receive their baseline audiograms if these tests are delayed due to mobile test van scheduling;
  • if they have incurred standard threshold shifts that demonstrate they are susceptible to noise; and
  • if they are exposed to noise over the permissible exposure limit of 90 dB over an 8-hour TWA.

Employers should provide employees with a selection of at least one variety of hearing plug and one variety of hearing muffs.

Example of EPA's active and passive NRR label.
Example of EPA's active and passive NRR label.

Noise Reduction Ratings (NRR)

Hearing protectors must adequately reduce the noise level for each employee’s work environment. Most employers use the Noise Reduction Rating (NRR) that represents the protector’s ability to reduce noise under ideal laboratory conditions. The employer then adjusts the NRR to reflect noise reduction in the actual working environment.

Standard Threshold Shift (STS)

OSHA's definition of a standard threshold shift is a change, relative to baseline, of 10 dB or more in the average hearing level at 2000, 3000, and 4000 Hz in either ear.

NIOSH’s definition of significant threshold shift is a 15 dB change at any of the frequencies 500, 1000, 2000, 3000, 4000, or 6000 Hz, demonstrated on a repeat audiogram for the same ear and same frequency, with the retest being administered immediately after the audiogram that showed the shift as compared to the baseline audiogram.

Training can motivate employees.
Employees that receive training will be more motivated to wear hearing protection and take audiometric tests.

What Training is required?

Employee training is very important. Workers who understand the reasons for the hearing conservation programs and the need to protect their hearing will be more motivated to wear their protectors and take audiometric tests.

Employers must train employees exposed to TWAs of 85 dB and above at least annually in:

  • the effects of noise;
  • the purpose, advantages, and disadvantages of various types of hearing protectors;
  • the selection, fit, and care of protectors; and
  • the purpose and procedures of audiometric testing

The training program may be structured in any format, with different portions conducted by different individuals and at different times, as long as the required topics are covered.

Employers must retain records.
Employers must keep noise exposure measurement records for 2 years and maintain records of audiometric test results for the duration of the affected employee’s employment.

What exposure and testing records must employers keep?

Employers must keep noise exposure measurement records for 2 years and maintain records of audiometric test results for the duration of the affected employee’s employment. Audiometric test records must include the employee’s name and job classification, date, examiner’s name, date of the last acoustic or exhaustive calibration, measurements of the background sound pressure levels in audiometric test rooms, and the employee’s most recent noise exposure measurement.

Employers are required to record work-related hearing loss cases when an employee’s hearing test shows a marked decrease in overall hearing. Employers will be able to make adjustments for hearing loss caused by aging, seek the advice of a physician or licensed health-care professional to determine if the loss is work-related, and perform additional hearing tests to verify the persistence of the hearing loss.

Management Responsibilities

Managers should support the audiometric evaluation phase by allocating sufficient resources. Management must ensure all employees (even mobile/itinerant workers) are included in the audiometric phase.

Management may opt to contract for audiometric services with an external source such as a mobile testing contractor or a local hearing clinic. Alternatively, management may choose to purchase audiometric equipment and train a company employee to perform audiometric testing on-site under the supervision of an audiologist or a qualified physician. The third option is to combine internal and external resources. The choice depends upon economic considerations as well as the size, policies, and geographical location of the company. If contract services are used, it is critically important that management still assign responsibility for overseeing the hearing conservation program to a key on-site individual.

All employees, not just those with threshold shifts, should receive prompt written summaries of their current hearing status from the professional reviewer. Employees also should receive summaries of their hearing trends over time, along with recommendations for further evaluation or any extra precautions needed, such as more careful use of hearing protectors.

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Instructions

Before beginning this quiz, we highly recommend you review the module material. This quiz is designed to allow you to self-check your comprehension of the module content, but only focuses on key concepts and ideas.

Read each question carefully. Select the best answer, even if more than one answer seems possible. When done, click on the "Get Quiz Answers" button. If you do not answer all the questions, you will receive an error message.

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1. Employers must monitor all employees whose noise exposure is equivalent to or greater than a noise exposure received in 8 hours where the noise level is constantly _____ dB.

2. Employers must provide _____ audiograms within 6 months of an employee's first exposure at or above an 8-hour TWA of 85 dB.

3. Employers must provide annual audiograms within _____ year of the baseline.

4. For maximum protection of the employees (and for that matter, the company), audiograms should be performed on the following occasions:

5. NIOSH's definition of significant threshold shift is a _____ dB change at any of the frequencies 500, 1000, 2000, 3000, 4000, or 6000 Hz, demonstrated on a repeat audiogram for the same ear and same frequency, with the retest being administered immediately after the audiogram that showed the shift as compared to the baseline audiogram.


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