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Noise, or unwanted sound, is one of the most pervasive occupational health problems. It is a by-product of many industrial processes. Sound consists of pressure changes in a medium (usually air), caused by vibration or turbulence. These pressure changes produce waves emanating away from the turbulent or vibrating source. Exposure to high levels of noise causes hearing loss and may cause other harmful health effects as well. The extent of damage depends primarily on the intensity of the noise and the duration of the exposure.
OSHA requires employers to determine if workers are exposed to excessive noise in the workplace. If so, the employers must implement feasible engineering or administrative controls to eliminate or reduce hazardous levels of noise. Where controls are not sufficient, employers must implement an effective hearing conservation program.
Scope
OSHA’s hearing conservation is designed to protect general industry employees, such as those working in the manufacturing, utilities, and service sectors. It does not cover the construction or the oil and gas well drilling and servicing industries. General industry employers with certain noise levels are required to take certain actions:
- TWA exposures at or above the action level of 85 dBA or, equivalently, a dose of 50 percent, require a hearing conservation program.
- TWA exposures exceeding the PEL (90 dBA as an 8-hour TWA, see Table G-16) require feasible engineering or administrative controls to be implemented.
Regulatory citations
- 29 CFR 1910.95 — Occupational noise exposure
Key definitions
- Action level: An 8-hour time-weighted average of 85 decibels measured on the A-scale, slow response, or equivalently, a dose of fifty percent.
- Audiogram: A chart, graph, or table resulting from an audiometric test showing an individual’s hearing threshold levels as a function of frequency.
- Baseline audiogram: The audiogram against which future audiograms are compared.
- Decibel (dB): Unit of measurement of sound level.
- Noise dosimeter: An instrument that integrates a function of sound pressure over a period of time in such a manner that it directly indicates a noise dose.
- Representative exposure: Measurements of an employee’s noise dose or 8-hour time-weighted average sound level that the employers deem to be representative of the exposures of other employees in the workplace.
- Time-weighted average sound level: That sound level, which if constant over an 8-hour exposure, would result in the same noise dose as is measured.
Summary of requirements
Employers are required to do the following:
- Administer a continuing, effective hearing conservation program IF employee noise exposures equal or exceed an 8-hour time-weighted average sound level (TWA) of 85 decibels measured on the A scale (slow response); OR equivalently, a dose of fifty percent.
- Institute a training program for all employees who are exposed to noise at or above an 8-hour time-weighted average of 85 decibels, AND ensure employee participation in such program.
- Make copies of 1910.95 available to affected employees or their representatives and also post a copy in the workplace.
- Use feasible administrative or engineering controls where needed.
- Establish and maintain an audiometric testing program by making audiometric testing available to all employees whose exposures equal or exceed an 8-hour time-weighted average of 85 decibels.
- Develop and implement a monitoring program if information indicates that any employee’s exposure may equal or exceed an 8-hour time-weighted average of 85 decibels.
- Maintain an accurate record of all employee exposure measurements required.
- Make hearing protectors available, at no cost, to all employees exposed to an 8-hour time-weighted average of 85 decibels or greater.
- Evaluate hearing protector attenuation for the specific noise environments in which the protector will be used.