Changes to Prevent Hearing Losses in Workers Recommended by NIOSH

Contact: Fred Blosser (202) 260-8519
September 16, 1998

A new criteria document by the National Institute for Occupational Safety and Health (NIOSH) recommends several key technical steps to better protect workers from job-related hearing loss, a disorder that currently costs the economy about $1 billion every year. NIOSH estimates that more than 30 million U.S. workers are exposed to hazardous noise, and an additional 9 million are at risk from exposures that may damage hearing, such as heat and certain chemicals.

The document recommends changes in technical methods used in workplace programs to monitor workers’ hearing and avoid overexposures to noise. These changes would better identify workers at risk of potential hearing damage, limit their exposure to harmfully loud noises, and aid workers in selecting the most protective earplug or earmuff where such devices are needed.

Based on a new risk assessment, the document also reaffirms NIOSH’s standing recommendation that a worker’s average noise exposure over an eight-hour work day should not exceed 85 decibels, A-weighted (dBA). That level is equivalent to the noise heard three feet away from an electric drill going into a piece of wood, for example. At 85 dBA, two people standing only three feet from each other would have to shout to hold a conversation. A-weighting refers to a scale on a sound-measurement meter that approximates human hearing. The current permissible limit for exposure is 90 dBA.

“Too often, job-related hearing losses are erroneously regarded as a fact of life and a natural effect of aging, but nothing could be further from the truth,” said NIOSH Director Linda Rosenstock, M.D., M.P.H. “In fact, hearing losses caused by overexposures to noise at work are preventable conditions that impose needless burdens on workers, their families, businesses, and society. Although our recommendations are technical in nature, they would have everyday benefits for improving quality of life and saving significant costs.”

NIOSH criteria documents are scientific documents that serve a variety of purposes. They provide scientific input for consideration by the U.S. Department of Labor’s Occupational Safety and Health Administration (OSHA) in policy deliberations, and they also receive wide use by technical specialists, industry, health professionals, and others as technical guidance in designing effective safety and health programs. NIOSH is a part of the Centers for Disease Control and Prevention in the U.S. Department of Health and Human Services.

In large part, current industrial procedures established under OSHA standards to test workers’ hearing and take steps to protect hearing are based on previous NIOSH research and recommendations. The new criteria document updates this research, much of it now more than 25 years old, in light of more recent data and current analytical techniques.

Recommendations in the document include:

• A more stringent formula for limiting the time workers could be exposed to specific noise levels over 85 dBA during an eight-hour work day.
• More frequent monitoring of noise exposures than current standards require.
• More protective and accurate methods for identifying diminutions in hearing that signal a need for follow-up with the worker to prevent further loss.
• No adjustments for age when calculating diminutions in hearing associated with workplace exposures. For many individuals, age does not mean a degradation in hearing.

Hearing loss is one of 21 priority areas identified in the National Occupational Research Agenda (NORA) as areas in which national research is most critical for protecting workers from job-related injury and illness over the next decade. NORA was developed with extensive public review and wide interaction among NIOSH and diverse partners in industry, labor, government, academia, and the health and safety community.

“NIOSH Criteria for a Recommended Standard: Occupational Noise Exposure,” DHHS (NIOSH) Publication 98-126, is available by calling the NIOSH toll-free information number, 1-800-35-NIOSH (1-800-356-4674). The text of the document and information on other NIOSH research are available at NIOSH’s home page on the World Wide Web at www.cdc.gov/niosh.