Very loud sounds can cause the hair cells of the inner ear to collapse and flatten temporarily, resulting in deafness. This may be temporary or permanent, depending on the noise level and length of exposure. Temporary hearing loss may also be accompanied by a ringing sensation called tinnitus.
If high noise exposure is repeated over many years, the hair cells in the inner ear may also become permanently damaged resulting in permanent hearing loss.
Immediate permanent hearing loss can also occur if someone is exposed to very intense or explosive sounds e.g. a gunshot or explosion. This type of damage is known as acoustic trauma. In some cases a very intense sound can actually perforate the eardrum.
The harmful effects of noise may be cumulative and not necessarily confined to the workplace. For instance, the use of personal stereo units and frequenting nightclubs may result in young people having some early damage to their hearing before they even join the workforce.
Dangerous noise levels
As people respond differently to noise, the exact level at which noise will cause damage is not certain for each person. However, the amount of damage caused by noise depends on the total amount of energy received over time and each person's susceptibility to hearing loss.
Most people are protected from long-term damage in a working day (8 hours) by keeping exposure around the 85 decibel (dB)(A) level. But if noise exposure becomes more intense, damage may occur in a shorter time.
The acceptable noise exposure standard in the workplace is 85 dB(A) averaged over an eight-hour period. This is not to imply that a safe condition exists at below 85 dB(A). It simply means that an eight-hour exposure of 85 dB(A) is considered to represent an acceptable level of risk to hearing health in the workplace.
Source: Safework South Australia 2016