Noise is one of the most common occupational hazards. According to the United States Department of Labor, approximately 30 million people are occupationally exposed to hazardous noise every year. Consequently, thousands of workers are suffering from hearing loss. In 2009, the Bureau of Labor Statistics reported more than 21,000 cases of permanent hearing loss among workers.

The problem is that while noise is a serious hazard with serious consequences, many people overlook it. Here's what you need to know about noise - and how to prevent-noise-related hazards on the job.

Sound vs. Noise

Sound is what we hear, while noise is unwanted sound. The difference between sound and noise depends on the individual exposed and the circumstances. In either case, both can adversely affect a person’s hearing if the sound is loud and if he or she is has been exposed to it over a prolonged period.

The Hazards of High Noise Levels

Exposure to extreme levels of noise can cause permanent hearing loss, which neither surgery nor a hearing aid can correct. Short-term exposure to loud noise can also cause a temporary change in hearing or tinnitus (a ringing in the ears). Repeated exposure to loud noise can lead to permanent tinnitus and/or hearing loss.

Apart from damage to hearing, constant exposure to excessively loud noise can cause other problems, such as physical and psychological stress (headaches, elevated blood pressure and fatigue), reduced productivity, impaired communication and concentration, and increased workplace accidents and injuries.

How is noise measured?

Noise is measured in units of sound pressure called decibels using A-weighted sound levels (dBA). Decibels are measured on a logarithmic scale. That is, even a small increase in the number of decibels will results in an increase in the amount of noise and thus, potentially damage a person's hearing.

Noise Standards

The legal limit set by the Occupational Safety and Health Administration (OSHA) regarding noise exposure in the workplace is based on an employee's time-weighted average over an eight-hour day. OSHA's permissible exposure limit (PEL) is 90 dBA for all employees for an eight-hour day.

The National Institute for Occupational Safety and Health (NIOSH) has also recommended that all employee exposures to noise be controlled below a level equivalent to 85 dBA for eight hours to minimize occupational noise-induced hearing loss.

How can you tell if your workplace is too loud?

  • You often have to raise your voice for others to hear you.
  • There is a ringing or humming in your ear at the end of a work shift.
  • You experience temporary hearing loss after leaving work each day.

What can employees do to protect their hearing at work?

Since there is no cure for noise-induced hearing loss, hearing protection is extremely important. Employees can protect their hearing in the workplace by using the most appropriate hearing protection devices (HPDs). There are three types of HPDs: earmuffs, earplugs and semi-insert earplugs. Each of these devices has a noise reduction rating (NRR), which is listed on the packaging. The NRR is used to evaluate the device’s ability to protect hearing from specific sound levels. When the time-weighted exposure is over 100 dBA, both earmuffs and earplugs should be worn together.

How can employers reduce noise in the workplace?

Some examples of inexpensive but effective control measures that employers can implement to ensure the protection their employees’ hearing include:

  • Engineering controls achieved by modifying or replacing equipment, or by making physical changes at the source of the noise or along its transmission path. This includes selecting quiet tools and machinery, maintaining and lubricating machinery and equipment, placing a barrier between the noise source and employees, and enclosing or isolating the noise source.
  • Administrative controls achieved by making changes to the work environment. These include operating noisy machines during shifts when fewer people are exposed, limiting the amount of time a person spends at a noise source, providing quiet areas where workers can gain relief from hazardous noise sources, and restricting worker presence to a safe distance away from noisy equipment.

Hearing Conservation Program

An effective hearing conservation program must be implemented by all employers whenever the level of noise is greater than 85 dBA for an eight-hour period, or in the construction industry when levels exceed 90 dBA for an eight-hour exposure. The aim of a hearing conservation program is to prevent initial occupational hearing loss and preserve and protect remaining hearing, as well as equip workers with the knowledge and hearing protection devices necessary to protect them.

Listen Up for Hearing Loss

Protecting hearing is often a low priority, both for workers and their employers. This is due to the fact that most people are unaware of the serious effects of hazardous noise. Even though employees are educated and trained on good hearing protection practices, most of them fail to comply. Most employees are oblivious to the fact that loud sounds and noises can permanently damage their hearing. This is because many employees may not notice any effects or changes in their hearing over the short term. That means more emphasis need to be placed on creating a safety culture associated with hearing protection in the workplace.