Many jobs, from construction to manufacturing, can expose workers to high levels of noise for significant periods of time, which can lead to irreversible hearing loss. For example, the operation of commercial dishwashing machines in a restaurant/food processing facility or the use of grinders to polish metal in a manufacturing plant can all cause noise-related injury. Each year, approximately 22 million workers in the United States are exposed to noise levels that are considered hazardous to their health. These occupational exposures account for nearly one-quarter of hearing difficulties experienced by workers. Additionally, intense noise can reduce work productivity and contribute to accidents and injuries by interfering with communication and making it more difficult to hear warning signals.
A number of factors can contribute to an individual’s hearing loss, including:
- Intensity or sound level of the noise
- Amount of time spent in the noisy area
- Frequency (wavelength) of the noise exposure
- Presence of impulsive noise (a loud noise that occurs intermittently but does not last)
Hearing loss warning signs and symptoms your workers should be aware of include:
- Ringing or humming in the ears when away from work
- Difficulty hearing coworkers who are located close by (an arm’s length away)
- Temporary hearing loss after leaving work
Protecting Against Noise-Related Damage
The Occupational Safety and Health Administration (OSHA) sets legal limits on noise exposure in the workplace. At specific levels, businesses are required to take measures to help reduce the impact of noise and protect their workers’ hearing. The level of noise is measured as a time-weighted average (TWA) over the course of an eight-hour period as decibels on the A scale (dBA). Employees can be exposed to higher levels of sound for shorter periods or lower levels of sound for longer periods, as long as the total exposure does not exceed the limits set by OSHA.
Noise control is the first line of defense against damage, and OSHA outlines requirements for businesses when noise reaches specific levels of exposure.
Hearing conservation program: If workplace noise exposures equal or exceed 85 dBA as an eight-hour TWA, similar to the sounds of a passing motorcycle at 50 feet away, a business must implement and maintain a hearing conservation program until the exposure drops below that threshold. Noise monitoring must be repeated whenever there are changes in production volume, processes, equipment, or controls that increase noise exposures. The program should:
- Identify exposed workers.
- Identify and reduce major noise sources through engineering controls, if feasible.
- Use hearing protectors, such as earplugs or earmuffs.
- Conduct audiometric testing to monitor employee hearing over time.
- Train employees on noise effects, use of hearing protectors, and the purpose of audiometric exams.
Engineering and administrative controls: When noise exposures in a workplace exceed 90 dBA as an eight-hour TWA, similar to the sound of a gas-powered lawnmower or electric arc welder, a business must implement engineering and administrative controls in addition to the required hearing conservation program. Administrative controls include decreasing time spent conducting noisy tasks or rotating job functions to reduce the amount of time workers spend exposed to noise. Engineering controls include modifying or replacing equipment or making physical changes at the noise source. Here are some examples:
- Adjust worker schedules or job tasks to limit exposure.
- Choose low-noise tools and machinery.
- Fit compressed air lines with energy-efficient, quiet-design safety nozzles/guns that reduce or limit noise output when in use.
- Reduce air pressure being supplied to equipment to the minimum necessary to accomplish the task.
- Ensure air-powered tools have mufflers.
- Maintain and lubricate machinery and equipment.
- Place a barrier, such as a wall or partition, between the noise source and the employee.
- Provide properly fitted hearing protection devices, such as earplugs or earmuffs.
- Enclose or isolate the noise source.
Employee hearing loss can result in additional risks in the workplace. Workers may find themselves in dangerous situations as a result of not being able to hear warning signs, or they may suffer physical or emotional pain as a result of noise-related injuries. Additionally, businesses may experience an increase in workers compensation claims and lost productivity. By addressing the root causes of excessive noise, you can help protect your employees against hearing loss and help maintain a productive and healthy workplace.