Occupational Hearing Loss

According to the National Institute for Occupational Safety and Health (NIOSH), hearing loss is the third-most common chronic physical condition among adults in the United States, after hypertension and arthritis.

The Centers for Disease Control and Prevention (CDC) states that four million workers go to work each day in damaging noise conditions. Ten million people in the U.S. have a noise-related hearing loss. Twenty-two million workers are exposed to potentially damaging noise each year.

About 11% of the U.S. working population has hearing difficulty, with 24% caused by occupational exposures. Tinnitus (‘ringing in the ears’) affects 8% of the working population, and 4% has both hearing difficulty and tinnitus.

OHL can occur when workers are exposed to loud noise or ototoxic chemicals.

Ototoxic chemicals (and examples) include:

  • Organic solvents (styrene, trichloroethylene, mixtures);
  • Heavy metals (mercury, lead, trimethyltin); and
  • Asphyxiants (carbon monoxide, hydrogen cyanide).

Noise is considered loud (hazardous) when it reaches 85 decibels or higher, or if a person has to raise his/her voice to speak with someone 3 feet away (arm’s length).

OSHA mandates that employers must incorporate a hearing conservation program when workers are exposed to noise levels that average 85dB over an 8-hour workday. 85dB sounds like a diesel truck, a snow blower, or a milling machine. 90dB sounds like a power mower, an arc welder, or a newspaper press.

100dB – which is damaging to human hearing when exposure last for prolonged periods of time – is equivalent to the sound of a jet taking off, a farm tractor, or a jackhammer. None of these are uncommon sounds for many average working Americans.

The NIOSH OHL Surveillance Project commenced to establish a national repository for OHL data, and to conduct surveillance and research of this common occupational illness.

OHL surveillance includes:

  • Collecting worker hearing data, exposure data and related information for analysis;
  • Estimating how many workers have hearing loss or related health outcomes and how many workers are exposed;
  • Examining these estimates by industry and occupation; and
  • Monitoring trends over time.