Document ID: chunk:federal_register_of_legislation:F2016L00426:reg:0:p16
Version: federal_register_of_legislation:F2016L00426
Segment Type: reg
Provision Reference: reg 0 (pt 16/20)
Character Range: 64409–68172

established, it is recommended that the daily noise exposure of workers exposed to any of the substances listed in Table A1 be reduced to 80 dB(A) or below. They should also undergo audiometric testing and be given information on ototoxic substances.
Control measures such as substitution, isolation and local ventilation should be implemented to eliminate or reduce chemical exposures. Personal protective equipment should be used to prevent skin and respiratory absorption when other controls are insufficient.

Table A1 Some common ototoxic substances [3]

Type                                                          Name              Skin Absorption
Solvents                                                      Butanol           √
Carbon disulphide                                             √
Ethanol
Ethyl benzene
n-heptane
n-hexane
Perchloroethylene
Solvent mixtures and fuels  Stoddard solvent (white spirits)  √
Styrene
Toluene                                                       √
Trichloroethylene                                             √
Xylenes
Metals                                                        Arsenic
Lead
Manganese
Mercury                                                       √
Organic tin                                                   √
Others                                                         Acrylonitrile    √
Carbon monoxide
Hydrogen cyanide                                              √
Organophosphates                                              √
Paraquat

Acoustic Shock
Acoustic incidents are sudden, unexpected loud noises occurring during telephone headset use, including crackles, hisses, whistles, shrieks or high-pitched noises. Acoustic shock is not caused by the loudness of a telephone, as all phone noise is electronically limited to a peak noise level of 123 decibels, but by a sudden rise in noise levels.
The noises can come from a wide variety of sources, either within the transmission system or from the customer end. Sources of acoustic incidents include those outlined in Table A2:

Table A2 Sources of acoustic incidents

Sources within the transmission system                              Sources from the customer end

    * faulty or damaged networks, telephones and headset equipment      * feedback oscillation from some cordless phones
    * broadband and narrowband interference                             * alarm signals
    * mobile phones or fax machines used in call centres                * phone receivers slammed down or dropped
                                                                        * tones from misdirected facsimiles and modems
                                                                        * noises made close to the receiver (eg. whistling)

Although acoustic incidents occur in workplaces (mainly call centres), only a very small proportion cause the symptoms known as 'acoustic shock' in workers.
High background noise levels at the workplace can increase the risk of acoustic shock occurring from an acoustic incident. For example, operators may raise the volume in their headsets to improve hearing thereby increasing the impact of any sudden, loud telephone noise. When an acoustic incident occurs, the operator's automatic reaction may be to remove the headset or receiver as quickly as possible and, in some cases, this may help prevent or reduce the effects
of acoustic shock.
Other factors, such as a middle ear inflammation and feelings of tension, may increase the likelihood of an acoustic shock resulting from an acoustic incident.

Acoustic shock symptoms
The effect on individuals can vary greatly for the same increase in sound level. Only a small number of people develop symptoms from an acoustic incident. Why a