Federal public servants working on telephones are being told by their union they are at risk of serious injury and to be careful of permanent hearing loss.
The Community and Public Sector Union is surveying members working for the Australian Taxation Office - which has 20,000 staff, many of whom spend a lot of time using phones - as well as other government workers on how much they know about the dangers of telephones.
The union has called for audiometric tests to be done on all government workers before they start work using phones to deal with members of the public.
"We have concerns about current standards of practice in some areas, and the risk to your health and wellbeing," a statement to members said.
"The CPSU believes employees who spend a significant portion of their time at work on the phone are at risk of serious injury."
The union and ATO management have been involved in protracted enterprise agreement negotiations.
On Tuesday an ATO spokesperson said there had been two reports of audio shock or audio shriek incidents in the past four months.
"The ATO take the health and safety of all employees seriously and ensure that there is appropriate training for staff in call centres or those engaged in high levels of phone work," the spokesperson said.
"We ensure that staff using headsets are trained in their correct use and have appropriate supervision.
"Our telephony staff are also provided with wireless headsets with inbuilt electronic noise limiting features, appropriate for telephony work."
In its statement to members the CPSU said acoustic shock was a serious injury "which may affect anyone working in a telephony environment".
"An incident can occur when an operator is exposed to a high pitched tone or other noise (loud or soft)," the CPSU said.
"These noises may be caused by noise on the other end of the phone, power surges, weather events like thunder or other factors.
"In the worst cases, people who experience acoustic shock injuries can suffer permanent hearing loss, though this is rare."
The union said it was important to have a baseline audiometric test for all employees before they started work in a "telephony environment" because it measured a person's hearing before they began this type of work.
"This can be referred to down the track if an employee experiences an acoustic incident, and can be critical in any potential compensation claim," the union said.
"Ensuring you have a safe workplace is a fundamental aspect of effective and responsible management.
"We think audiometric tests should be a standard practice for all employees handling government telephone enquiries, whether they work as a government employee or for another organisation providing the service for the government."
Its online survey asks public servants questions such as "have you been trained in how to identify an acoustic incident?" and "have you been trained in proper fitting and use of headsets?".