Hearing Conservation for Noise-Exposed Workers

The action level: 85 decibels

Your employer must run a continuing, effective hearing conservation program whenever your noise exposure equals or exceeds an 8-hour time-weighted average (TWA) of 85 decibels on the A scale, or a dose of 50 percent. This is called the action level.

Your exposure for the program is figured without counting any protection from your earplugs or earmuffs.

Signs noise may be that high

OSHA's informational appendix lists complaints about how loud it is, signs that employees are losing their hearing, and noise that makes normal conversation difficult.

Measuring and telling you

• When information shows exposure may reach 85 decibels TWA, your employer must set up a monitoring program.
• If you are exposed at or above 85 decibels TWA, you must be notified of the monitoring results.
• You or your representative must get the chance to observe the noise measurements.

Reference: 29 CFR 1910.95(c)(1) · 29 CFR 1910.95(c)(2) · 29 CFR 1910.95(d)(1) · 29 CFR 1910.95(e) · 29 CFR 1910.95(f) · 29 CFR 1910.95(o) · 29 CFR 1910.95 Appendix G

When you must wear them

If you are exposed at or above an 8-hour TWA of 85 decibels, your employer must make hearing protectors available to you at no cost and replace them as necessary. You must be given the chance to choose from a variety of suitable protectors your employer provides.

Your employer must make sure you wear them when

• Your exposure is above the Table G-16 limits and controls have not brought it within the table, or
• You are exposed at 85 decibels TWA or more and you have had a standard threshold shift, or
• You are exposed at 85 decibels TWA or more and are waiting for a baseline audiogram under the mobile test van provision. Where the baseline comes more than 6 months after your first exposure at or above the action level, you wear protectors for any period beyond six months until the baseline is done.

Reference: 29 CFR 1910.95(i)(1) · 29 CFR 1910.95(i)(2)(i) · 29 CFR 1910.95(i)(2)(ii)(A) · 29 CFR 1910.95(i)(2)(ii)(B) · 29 CFR 1910.95(g)(5)(ii) · 29 CFR 1910.95(i)(3)

Fit, attenuation and care

Attenuation is how much a protector reduces the noise reaching your ears. Under EPA rules, the Noise Reduction Rating (NRR) must be shown on the package.

• Protectors must reduce your exposure at least to an 8-hour TWA of 90 decibels.
• If you have had a standard threshold shift, they must reduce it to an 8-hour TWA of 85 decibels or below.
• If noise increases so your protectors may no longer be enough, attenuation must be re-evaluated, and more effective protectors provided where necessary.

Your employer must make sure you are told the purpose of hearing protectors, the advantages, disadvantages and attenuation of the various types, and how to select, fit, use and care for them. Your employer's training program is repeated annually for everyone in the hearing conservation program.

Reference: 29 CFR 1910.95(i)(4) · 29 CFR 1910.95(i)(5) · 29 CFR 1910.95(j)(2) · 29 CFR 1910.95(j)(3) · 29 CFR 1910.95(j)(4) · 29 CFR 1910.95 Appendix B · 29 CFR 1910.95(k)(3) · 29 CFR 1910.95(k)(3)(ii) · 29 CFR 1910.95(k)(2)

Baseline and annual audiograms

An audiogram is the chart, graph or table from a hearing test that shows your hearing threshold levels at different frequencies. Your employer must make audiometric testing available, at no cost to you, if your exposure equals or exceeds an 8-hour TWA of 85 decibels.

The baseline

• Your employer must establish a valid baseline audiogram within 6 months of your first exposure at or above the action level. (A mobile test van allows up to 1 year, with hearing protectors as described earlier.)
• The baseline test must follow at least 14 hours without workplace noise. Wearing hearing protectors can substitute for those 14 quiet hours.
• You must be told to avoid high levels of non-work noise during the 14 hours right before the test.

Every year after

If you are exposed at or above an 8-hour TWA of 85 decibels, your employer must obtain a new audiogram at least annually after the baseline. Each annual audiogram is compared with your baseline to see whether it is valid and whether a standard threshold shift has occurred.

Reference: 29 CFR 1910.95(g)(1) · 29 CFR 1910.95(g)(2) · 29 CFR 1910.95(g)(5)(i) · 29 CFR 1910.95(g)(5)(iii) · 29 CFR 1910.95(g)(5)(iv) · 29 CFR 1910.95(g)(6) · 29 CFR 1910.95(g)(5)(ii) · 29 CFR 1910.95 Appendix I · 29 CFR 1910.95(g)(7)(i)

Standard threshold shift: what happens next

A standard threshold shift (STS) is a change in your hearing threshold, compared with your baseline, of an average of 10 dB or more at 2000, 3000 and 4000 Hz in either ear. It means your hearing has changed compared with your baseline audiogram.

If your annual audiogram shows an STS, your employer may get a retest within 30 days and use it as your annual audiogram. When deciding whether an STS has occurred, an allowance may be made for the effect of aging on hearing.

If your annual test shows an STS

• You must be told in writing within 21 days of the determination.
• Unless a physician determines the shift is not work related or aggravated by work noise:
  • If you were not using hearing protectors, you are fitted with them, trained in their use and care, and required to use them.
  • If you were using them, you are refitted and retrained, and given protectors with greater attenuation if necessary.
  • You are referred for a clinical audiological evaluation or an otological examination, as appropriate, if additional testing is necessary or if your employer suspects an ear problem caused or aggravated by wearing hearing protectors.
  • You are informed of the need for an otological examination if an ear problem unrelated to hearing protectors is suspected.

Reference: 29 CFR 1910.95(g)(7)(ii) · 29 CFR 1910.95(g)(10)(ii) · 29 CFR 1910.95(g)(7)(i) · 29 CFR 1910.95(g)(10)(i) · 29 CFR 1910.95(g)(8)(i) · 29 CFR 1910.95(g)(8)(ii) · 29 CFR 1910.95(g)(8)(ii)(A) · 29 CFR 1910.95(g)(8)(ii)(B) · 29 CFR 1910.95(g)(8)(ii)(C) · 29 CFR 1910.95(g)(8)(ii)(D)