Most people are aware of the dangers of loud noise. Exposure to high intensity sound for even a short period of time can cause damage to the inner ear, resulting in permanent hearing loss. Fortunately, occupational noise standards have been implemented and people are more conscience of protecting their hearing when working with loud equipment, listening to music, attending sports events and other recreational activities. The same consideration needs to be taken for children and noisy toys.
First let’s broadly review how the ear and hearing works. When sound enters the ear, it is transmitted to the middle and inner ear. In the middle ear, the three small bones amplify and transmit the vibrations generated by the sound to the inner ear. The inner ear contains the cochlea which is filled with fluid and very fine hair cells. These tiny hairs move with the vibrations and convert the sound waves into nerve impulses, which results in the sound we hear. When we are exposed to extremely loud sounds, these hair cells become damaged and cannot be repaired, resulting in permanent hearing loss.
In order to reduce the potential for noise induced hearing loss, the Occupational Safety and Health Administration (OSHA) regulates the legal limit of noise exposure in the workplace. These limits are based on an eight hour work day and state that the allowable exposure level is 90 dBA for that length of time. OSHA also states that for every increase of 5 dBA in noise, the amount of exposure time is cut in half. Meaning, the louder the sound, the less time it takes for damage to occur. The National Institute for Occupational Safety and Health (NIOSH) has even stricter guidelines. NIOSH recommends that noise in the workplace be below 85 dBA for and exposure time of eight hours. Furthermore, NIOSH states that for every increase in noise of 3 dBA, the amount of exposure time halves. For example, a sound at 85 dBA may take eight hours to cause permanent hearing loss, while a sound at 100 dBA can start damaging the inner ear or hearing after only 15 minutes of exposure time.
Parents may be unaware of how loud some seemingly innocent toys are and the hazardous effects they might have on their young child’s hearing. According to the Sight and Hearing Association, 19 of the 24 toys tested for the annual Noisy Toys List (2011) emitted sounds over 100 dB, which is similar to a chainsaw in the ear canal. Some toys when held close to the ear will emit sounds up to 120 dB, which is equivalent to a jet plane taking off. These toys can include vehicles with horns or sirens, talking dolls, cap guns, and musical instruments. There are standards set for toy manufacturers however; most kids play with toys by holding them or sitting next to them, which is much closer than the 50 cm guideline. Researchers found that taking the toys apart and covering the speakers with Elmer’s glue or clear packaging tape reduced the toy’s volume and made them safe for hours of play time. For an easier solution, parents could also try putting heavy duct tape over the speaker, taking the batteries out, discarding the noisy toys or not purchase them in the first place – if it sounds too loud, don’t buy it!
There are also Apps for measuring loudness. According to the Acoustical Society of America Apple iOS apps provide the most accurate sound level measurements. Some include NoiSee by NoiseLab, Noise Hunter by Inter.net2day and SoundMeter by Faber Acoustical. These apps can be useful to measure toys or other means of loud sounds too.
Parents and caregivers need to be aware of the dangers of loud sounds in all environments. Protect young ears and hearing while you can! For a list of the noisiest toys each year, visit www.sightandhearing.org.