Agricultural producers are exposed to loud noises in their work environment on a daily basis. Gradual hearing loss is common during the aging process, but noise-induced hearing loss can occur at any age. Noise-induced hearing loss is a result of exposure to high-intensity noise without proper hearing protection. Noise-induced hearing loss is preventable by reducing the level of noise at its source and correctly wearing appropriate personal protective equipment (PPE).
Mechanics of hearing and hearing loss
Sound goes into the ear canal and strikes the eardrum causing it to vibrate. The vibrations create waves that travel to the middle ear forming waves in the cochlea. The cochlea contains small hairlike cells called cilia that wave when they come in contact with the vibration. Once the vibration enters the cochlea, these waves send a signal to the brain, which interprets them as sounds. Hearing loss occurs when the cilia become flattened and eventually destroyed from overstimulation of sound that is too loud or that lasts too long. Once these hair cells (cilia) are destroyed they can never be replaced causing permanent hearing loss.
Noise levels and duration
Sound loudness or intensity is measured in decibels (dB). In the United States, the Occupational Safety and Health Administration (OSHA) establishes guidelines regarding exposure to high levels of noise and recommends that hearing protection be used when you are exposed to a minimum sound level of 90 dB for eight hours. However, some individuals have developed noise-induced hearing loss at lower levels.
Four ways to prevent noise-induced hearing loss
- Noise reduction – An easy way to reduce noise levels on your farm or ranch is to pay close attention to equipment maintenance such as regular lubrication and replacement of parts. Operating larger equipment at a lower speed can also reduce noise levels. The installation of vibration isolation pads under the legs of noisy equipment can reduce the noise from equipment vibration on a cement floor. Newer models of certain handheld equipment are equipped with flexible mountings to reduce noise from vibration.
- Noise isolation – When purchasing equipment, consider buying a tractor or skid-steer that is equipped with sound-reducing cabs and tightly fitting cab doors and windows. These changes can reduce the amount of noise that you hear inside the cab when operating the equipment.
- Administrative Controls – As an employer, you can control your workers’ exposure to noise by rotating their workstations to limit their exposure time to jobs with high noise levels. Set up a rotation that allows a worker to operate a noisy machine for a specific period of time and then rotate that person to a less noisy task. If a person already has a hearing problem, he or she should not work in high noise areas.
- Personal Protective Equipment (PPE) – Use and require your employees to use personal protective equipment such as earplugs and earmuffs to reduce noise exposure.
Personal Protective Equipment (PPE)
Hearing personal protective equipment (PPE) is measured according to its noise reduction rating (NRR) which is a single number that indicates the reduction in decibels when the PPE is properly used. Hearing PPE should have a noise reduction rating of at least 25 decibels. Remember that the rating is achieved only when the equipment is properly fitted and worn for the recommended period of time. Earplugs and earmuffs are the most widely used personal protective equipment to reduce noise levels.
Earplugs are either disposable or reusable.
- Are designed to fit into the ear opening.
- Should never be shared with others to reduce the risk of ear infections.
- Should be disposed of once removed from the ear.
- Are either pre-molded, moldable, or custom fit.
- Have a limited usage period.
- Should be disposed of when they are cracked, dirty, no longer pliable, or permanently deformed.
Ear muffs are designed to cover the ear and ear canal, so it is important to use muffs that are comfortable and fit properly. They can be used for years, and certain models can be used in combination with other safety equipment such as goggles, a hardhat, or respiratory protection. Remember that hearing protection needs to be used whenever you are exposed to loud noises.
When to visit the audiologist
An audiologist can perform a specialized hearing test called an audiogram to detect and diagnose hearing loss. You cannot fix hearing loss once it has started, but you can prevent the damage to your hearing from getting worse. The following are a few signs that you may have a problem with your hearing:
- You are turning up the volume on the TV or radio.
- You have difficulty understanding consonants in words and high notes of music.
- You have difficulty hearing a person’s voice when they are standing only a few feet away.
- Sound may be muffled after noise is stopped.
- You have ringing in your ears.
Source: Hearing loss and protection for agricultural producers. Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice. www.extension.org/pages/62258/hearing-loss-and-protection-for-agricultural-producers.