Ionising Radiation

Action plan for HSRs

Legal Standards

What is Ionising Radiation?

What are the health effects of Ionising Radiation?

Action Plan for Health and Safety Reps

As with all workplace hazards, ionising radiation should be dealt with in this way:

  1. Identification of the hazard (see information on the hazard, below) 
  2. Assessment of the risk
  3. Elimination or reduction of the risk
  4. Review and evaluation of any control strategies.

1 - Identification of hazard

  • Ensure your employer identifies any sources of ionising radiation and undertakes monitoring;
  • Ensure your employer monitors all workers who may be exposed to ionising radiation using a dosemeter, which is worn as a badge attached to clothing. At monthly intervals the dosemeter should be sent to a laboratory where the radiation exposure can be read
  • Note it is likely that your employer will need to employ someone with the relevant expertise to do this. The employer has a duty under Section 22(2)(b) of the OHS Act to employ or engage someone who is 'suitably qualified'.
  • Talk to members of your work group about the hazards of radiation and their control, and any effects they may be experiencing on a regular basis;
  • Investigate any past incidents.

2 - Assessment of risk

  • Ensure the employer assesses results of monitoring - keep a check on results;
  • Ensure your employer has an effective incident reporting procedure in place to record actual and potential exposure to radiation, unsafe conditions, and workers.

3 - Elimination/reduction of risk

Ensure your employer controls the risks of radiation following the preferred order of control methods:

  • takes all measures possible to avoid exposure;
  • isolates all sources of radiation by shielding, containment or remote handling;
  • maintains all radiation generating equipment in order to minimise radiation emitted and prevent any 'leakages';
  • implements engineering controls to reduce radiation levels;
  • develops safe practices work practices and procedures, and ensures they are followed;
  • provides suitable protective clothing and administrative controls, including job rotation and rest breaks, to limit the amount of time employees are exposed, where engineering controls are unavailable or ineffective to reduce exposure levels;
  • provides adequate information and training on any radiation hazards in the workplace. Training should include information on the sources of the radiation, the health effects, the control procedures in place and how they are monitored, safe work practices, personal protective equipment (PPE), emergency procedures and radiation monitoring programs where appropriate;
  • maintains all controls implemented;
  • develops back up options emergency procedures in the case of control measures failing.

The VTHC believes that the National occupational exposure standard of 20mSv per year, averaged over a period of 5 consecutive years, is too high.

4 - Review

Ensure:

  • the employer maintains on-going monitoring of the environment and worker exposure to check effectiveness of control methods;
  • you take up any immediate issues with your employer. Contact your union for further information and advice. 

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The Radiation Act 2005  - the purpose of which is "to protect the health and safety of all persons and the environment from the harmful effects of radiation" - commenced in Victoria on 1 September 2007, and gives effect to Victoria's commitment to the National Directory for Radiation Protection (NDRP), which outlines a common approach to be undertaken by Commonwealth, State and Territory Governments towards the management of radiation protection. 

The Radiation Amendment Act 2013 No. 59 (Vic) received Assent on 22 October 2013 - this amended the Radiation Act 2005 No. 62 (Vic). The Act provides for the security of certain radioactive material and prohibits the commercial operation of tanning units. It also provides for the issuing of improvement and prohibition notices for contraventions of the Act.  Commencement details are contained in s2 of the Act. Tanning unit provisions commence on 1 January 2015. The remainder of the Act will commence upon Proclamation or, if not otherwise, then on 1 June 2014.

The Radiation Regulations 2007, were made under Section 139 of the Radiation Act 2005 and, among other things:

  • Prescribe the activity concentration and activity of material that spontaneously emits ionising radiation and the prescribed circumstances for the purposes of the definition of radioactive material;
  • Prescribe radiation dose limits; and
  • Prescribe the radiation sources that require a current certificate of compliance prior to use of the source.

Under the regulations, the ionising radiation dose limits for occupational exposure are:

Circumstance

Dose limit

Receipt of ionising radiation doses in 5 consecutive calendar years

Effective dose of 20 millisievert per year averaged over the 5 year period

Receipt of ionising radiation doses in a consecutive 12 month period

Effective dose of 50 millisievert

Receipt of ionising radiation to the lens of an eye of a person in a consecutive 12 month period

Equivalent dose of 150 millisievert

Receipt of ionising radiation to the skin of a person in a consecutive 12 month period

Equivalent dose of 500 millisievert averaged over 1cm2 of any part of the skin regardless of the total area exposed

Receipt of ionising radiation to the hands and feet of a person in a consecutive 12 month period

Equivalent dose of 500 millisievert

The ionising radiation dose limits for public exposure are much lower:

Circumstance

Dose limit

Receipt of ionising radiation doses in a consecutive 12 month period

Effective dose of 1 millisievert

Receipt of ionising radiation to the lens of an eye of a person in a consecutive 12 month period

Equivalent dose of 15 millisievert

Receipt of ionising radiation to the   skin of a person in a consecutive 12 month period

Equivalent dose of 50 millisievert averaged over 1cm2 of any part of the skin regardless of the total area exposed

  • The Act and Regulations can be accessed from the Victorian Legislation website.
  • The Victorian Department of Health has an information page on radiation legislation

In addition to the above, under the Victorian Occupational Health and Safety Act, 2004, the employer has a duty of care to provide and maintain a safe and healthy working environment for all employees as far as reasonably practicable.  This means taking into account all relevant national standards, guides and codes of practice.

National Codes & Standards

The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) publishes Codes of Practice or Standards.

These Codes and Standards often have a significant impact on those conducting radiation practices or using radiation sources because States and Territories have agreed to implement many of these Codes via instruments such as licences or Regulations. Both Management and Use Licences within Victoria will refer to compliance with an applicable Code of Practice or Standard where one exists.

ARPANSA provide a comprehensive list of all currently published Codes and standards. Check the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) website and the Publications page for more information.

From time to time Codes and Standards are updated and new ones are developed. As States and Territories have agreed to implement these Codes as legislation, the Department encourages persons who have interests in radiation practices to participate in the development of these Codes and Standards.

The National Standard for limiting occupational exposure to ionising radiation - 1995, republished in 2002 (a joint then National Occupational Health and Safety Commission and National Health and Medical Research Council standard) - is clearly out of date, although it provides some guidance. It has no regulatory standing in Victoria. The Standard set the effective occupational dose limit at 20mSv per year, averaged over a period of 5 consecutive years. In the case of occupational exposure during pregnancy, the general principle is that the embryo or foetus 'should be afforded the same level of protection as is required for a member of the public'. The public dose limit is set at 1mSv in a year. This is in line with the International Commission on Radiological Protection (ICRP).

Two Australian Standards on laser safety are used in the Building industry: AS2397 and AS2211. The building industry award also had provisions for "Laser Safety Officers", who were required to have the relevant training (and were entitled to a daily allowance).  While awards have now been 'stripped back', this provision should have been transferred to EBAs.

Remember also that employers have a duty under the Victorian Occupational Health and Safety Act (2004) to provide and maintain for employees, as far as practicable, a working environment that is safe and without risks to health. This includes providing a safe system of work, information, training, supervision, and where appropriate personal protective equipment. The employer must also monitor conditions at the workplace. In addition, the Plant Code of Practice recommends that employers consider a number of Australian and other Standards on laser safety.

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There is absolutely no 'safe' level of exposure to ionising radiation.

What is Ionising Radiation?

Radiation is electromagnetic waves such as light, radio waves and X-rays, and the particles emitted by radioactive materials. These particles and the more energetic waves produce electrically charged particles - called 'ions'  - in the materials they strike. Ionising radiation is high frequency and high-energy and can penetrate the body - it has enough energy to break up atoms and molecules as it passes through the body (ie, it can cause ionisation).

Ionising radiation occurs as either electromagnetic rays (X-rays and gamma rays) or particles (such alpha and beta particles).

  • Alpha particles can be easily stopped (energy absorbed) by a piece of paper.
  • Beta particles can penetrate one or two centimetres of human tissue - but can be stopped by glass or metal.
  • Gamma rays and X-rays are waves of energy similar to visible light; except they have more energy and are invisible. They travel at the speed of light and penetrate matter more easily. They can be screened by lead, concrete or water.

More information on radiation in general

Where is it found?

Most ionising radiation in industry is due to X-rays. Equipment which emits X-rays can be found in:

  • Medical and dental diagnostic and therapeutic radiography;
  • Industrial radiography for detection of faults in welding or metal castings;
  • Testing instruments such as thickness gauges in sheet metal, plastic and paper production.

Gamma radiation is used in the sterilisation of medical and surgical equipment. Radioactive isotopes are used in the mineral industry, in analytical laboratories, in diagnostic pathology and in research.

Measurement

With higher frequency radiation, the dose is described in terms of energy absorbed by the body using the unit of sievert. Sieverts are very large units and doses are more commonly expressed as a microsievert (one millionth of a sievert) or a millisieverts (mSv - one thousandth of a sievert).

What are the health effects of exposure to Ionising Radiation?

When radiation is absorbed in the body it causes chemical reactions to occur which can alter the normal functions of the body. At high doses (above 1 sievert) this can result in massive cell death, organ damage and even death. At low doses (less than 50 mSv) the situation is more complex.

The body is made up of different cells (eg brain cells, muscle cells, blood cells etc). Different tissues in the body are affected by ionising radiation in different ways. It is the genes within a cell that determine how a cell functions. Even low doses of radiation can cause damage to the genes.

  • RADIATION SICKNESS:
    When the body is exposed to large doses of ionising radiation over a short period, for example as a result of a radiation accident - can lead to severe massive cell destruction and death of the person. This can occur very quickly, or over a longer period of time if the dose was smaller. Symptoms include nausea and vomiting, loss of hair, inflammation of the mouth and throat.
  • CANCER:
    A cell damaged by ionising radiation can lose its ability to control the rate at which it reproduces - this is cancer. Radiation at low doses can have this effect. The most common radiation induced cancers are leukaemia, skin tumours and thyroid cancer, though tumours in various other organs can also occur.
  • GENETIC DEFECTS & REPRODUCTIVE TOXICITY:
    If an unborn child is exposed to ionising radiation, then the chances that of the child then developing childhood cancer (especially leukaemia) are greater. Changes to basic cell structures (mutations) of reproductive cells (ova or sperm) can lead to miscarriages and birth defects.
  • CATARACTS:
    Clouding of the lens of the eye, eventually leading to blindness.
  • BLOOD CHANGES:
    Effects on the production of bone marrow resulting in a reduction of white blood cells and a less effective immunity system to fight infections
  • NERVOUS SYSTEM EFFECTS:
    Alteration of the electrical activity of the brain resulting in headache, fatigue, dizziness, changes in behaviour.
  • CARDIO-VASCULAR EFFECTS: Altered blood pressure; altered electrical activity of the heart.

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Last amended June 2015

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