Hearing Conservation: Noise Monitoring, Audiograms, and Hearing Protection

Noise at work can damage hearing over time. OSHA's occupational noise standard sets noise limits and tells you to reduce noise above them with feasible controls. At a lower level, called the action level, it requires a hearing conservation program: monitoring, hearing tests, hearing protectors, training, and records.

Who it applies to

The standard is in 29 CFR Part 1910, Subpart G. It has two triggers: sound levels above Table G-16 (1910.95(a)), and exposures at or above the action level (1910.95(c)(1)).

Paragraphs (c) through (n) do not apply to employers engaged in oil and gas well drilling and servicing operations (1910.95(o)). Construction has its own noise standard, 29 CFR 1926.52.

What the standard requires

Noise limits and controls

• Protection against the effects of noise must be provided when sound levels exceed those in Table G-16, measured on the A scale of a standard sound level meter at slow response (1910.95(a)). The table permits 8 hours per day at 90 dBA, with shorter durations at higher levels, down to 1/4 hour or less at 115 dBA (Table G-16).
• When employees are subjected to sound exceeding the table, you must use feasible administrative or engineering controls. If those controls fail to reduce sound levels within the table, personal protective equipment must be provided and used (1910.95(b)(1)).

The action level

You must administer "a continuing, effective hearing conservation program" whenever employee noise exposures equal or exceed an 8-hour time-weighted average (TWA) of 85 decibels measured on the A scale (slow response) or, equivalently, a dose of fifty percent (1910.95(c)(1)). The standard calls this the action level (1910.95(c)(2)).

Monitoring

• When information indicates that any employee's exposure may equal or exceed an 8-hour TWA of 85 decibels, you must develop and implement a monitoring program (1910.95(d)(1)).
• Notify each employee exposed at or above an 8-hour TWA of 85 decibels of the results (1910.95(e)).
• Give affected employees or their representatives an opportunity to observe noise measurements (1910.95(f)).

Audiometric testing

You must make audiometric testing available, at no cost, to all employees whose exposures equal or exceed an 8-hour TWA of 85 decibels (1910.95(g)(1), (g)(2)).

• Who may test. A licensed or certified audiologist, otolaryngologist, or other physician, or a technician who is certified by the Council of Accreditation in Occupational Hearing Conservation or has satisfactorily demonstrated competence. A technician must be responsible to an audiologist, otolaryngologist, or physician (1910.95(g)(3)).
• Baseline. Establish a valid baseline audiogram within 6 months of an employee's first exposure at or above the action level (1910.95(g)(5)(i)). Where mobile test vans are used, the deadline is 1 year, but employees must wear hearing protectors for any period exceeding six months after first exposure until the baseline is obtained (1910.95(g)(5)(ii)).
• Quiet period. Baseline testing must be preceded by at least 14 hours without exposure to workplace noise. Hearing protectors may be used as a substitute (1910.95(g)(5)(iii)).
• Annual audiogram. At least annually after the baseline, obtain a new audiogram for each employee exposed at or above an 8-hour TWA of 85 decibels (1910.95(g)(6)), and compare it to the baseline (1910.95(g)(7)(i)).
• Standard threshold shift (STS). A change in hearing threshold relative to the baseline of an average of 10 dB or more at 2000, 3000, and 4000 Hz in either ear (1910.95(g)(10)(i)).

When an STS occurs, unless a physician determines it is not work related or aggravated by occupational noise exposure, you must ensure that (1910.95(g)(8)(ii)):

• Employees not using hearing protectors are fitted with them, trained in their use and care, and required to use them.
• Employees already using protectors are refitted and retrained, and given protectors offering greater attenuation if necessary.
• The employee is referred for a clinical audiological evaluation or an otological examination, as appropriate, if additional testing is necessary or if you suspect wearing protectors causes or aggravates a medical pathology of the ear.
• The employee is informed of the need for an otological examination if a medical pathology of the ear unrelated to protector use is suspected.

Hearing protectors

• Available. Make hearing protectors available to all employees exposed to an 8-hour TWA of 85 decibels or greater, at no cost, and replace them as necessary (1910.95(i)(1)).
• Mandatory wear. Ensure protectors are worn by an employee required by paragraph (b)(1) to wear personal protective equipment, and by any employee exposed to an 8-hour TWA of 85 decibels or greater who has not yet had a baseline audiogram established pursuant to paragraph (g)(5)(ii), or who has experienced an STS (1910.95(i)(2)).
• Fit and use. Ensure proper initial fitting and supervise correct use (1910.95(i)(5)).
• Attenuation. Evaluate protector attenuation for the specific noise environments where it will be used, using one of the appendix B methods (1910.95(j)(1)). Protectors must attenuate exposure at least to an 8-hour TWA of 90 decibels (1910.95(j)(2)), and to 85 decibels or below for employees who have experienced an STS (1910.95(j)(3)).

Training

You must train each employee exposed to noise at or above an 8-hour TWA of 85 decibels (1910.95(k)(1)), and repeat the training program annually for each employee in the hearing conservation program (1910.95(k)(2)).

Each employee must be informed of (1910.95(k)(3)):

• The effects of noise on hearing.
• The purpose of hearing protectors, the advantages, disadvantages, and attenuation of various types, and instructions on selection, fitting, use, and care.
• The purpose of audiometric testing and an explanation of the test procedures.

Written programs and records

• Exposure measurements. Maintain an accurate record of all employee exposure measurements required by paragraph (d) (1910.95(m)(1)). Retain them for two years (1910.95(m)(3)(i)).
• Audiometric test records. Retain them for the duration of the affected employee's employment (1910.95(m)(3)(ii)).
• Audiometric test room records. Maintain accurate records of the measurements of the background sound pressure levels in audiometric test rooms (1910.95(m)(2)(ii)(F)).
• The standard itself. Make copies available to affected employees or their representatives and post a copy in the workplace (1910.95(l)(1)).

Easy-to-miss requirements

• Earplugs do not count when you calculate exposure. For the hearing conservation program, exposures are computed without regard to any attenuation provided by personal protective equipment (1910.95(c)(1)).
• Re-monitor after changes. Repeat monitoring whenever a change in production, process, equipment, or controls increases noise exposures to the extent that additional employees may be exposed at or above the action level, or protectors in use may no longer meet paragraph (j) (1910.95(d)(3)).
• STS notice in writing. The employee must be informed in writing within 21 days of the determination (1910.95(g)(8)(i)).
• Off-the-job noise. Notify employees of the need to avoid high levels of non-occupational noise during the 14 hours before the audiometric examination (1910.95(g)(5)(iv)).

Related guides

• PPE hazard assessment
• Respiratory protection

Source

This guide is based on the text of 29 CFR 1910.95 as published on osha.gov. The regulation itself always controls. States that run their own OSHA-approved State Plans may have additional or stricter rules.