Radiation is energy transmitted in waves or a stream of particles. Different types of radiation are used in a diverse range of industrial, medical, research and communications applications. Some can create harmful exposures that must be effectively controlled.
Radiation is typically categorised as ionising or non-ionising. The main difference is in the amount of energy the radiation carries. Ionising radiation carries more energy than non-ionising radiation.
Ionising radiation
Ionising radiations can damage living cells as they have enough energy to break molecules into electrically charged particles called ions. These ions can then take part in other chemical reactions in the living cells which may cause them to die or become cancerous.
Ionising radiation includes: X-rays, gamma rays, radiation from radioactive sources and sources of naturally occurring radiation, such as radon gas.
The use of ionising radiations in the workplace is well regulated. In most cases employers are required to:
- Notify HSE of their intention to work with ionising radiations;
- Conduct risk assessments prior to working with ionising radiations;
- Obtain advice from a radiation protection advisor on the adequacy of controls;
- Restrict worker’s exposure to ionising radiations through engineering controls, safe systems of work and personal protective equipment;
- Provide workers with information, instruction and training on the risks to health and required precautions; and
- Monitor worker’s exposure to ensure that dose limits are not exceeded
Practically, workers exposure to ionising radiation is controlled through:
- Distance – most radiation energy used in industry will not travel far in air so small separation distances can make a difference;
- Shielding – to keep the energy away from workers;
- Time – the adverse health effects depend on the dose received. The longer people are exposed the greater the dose received.
Non-ionising radiation
Non-ionising radiation includes:
- visible light (and lasers);
- ultra-violet light (from man-made sources and sunlight);
- infra-red radiation, and
- electromagnetic fields (microwaves and radio waves).
European Directives on artificial optical radiation and electromagnetic fields require employers to carry out a technical risk assessment where exposure could cause a foreseeable risk of adverse health effects.
Where a risk assessment is required the following steps must also be taken:
- The risk should be eliminated, or where that is not reasonably practicable, reduced to as low a level as is reasonably practicable;
- an action plan comprising technical and organisational measures should be devised to prevent exposure exceeding the exposure limit values;
- work areas where exposure limit values may be exceeded should be demarcated, warning signs displayed and access controlled;
- workers should be provided with information and training on the adverse health effects and required control measures; and
- arrangements should be made to provide health surveillance and medical examination to identify early signs of damage.
Ultra violet radiation from the sun (Solar radiation)
Solar radiation is an occupational hazard for people who work outdoors.
Exposure to ultraviolet (UV) radiation from the sun can cause skin damage including sunburn, blistering, skin ageing and in the long term can lead to skin cancer. Skin cancer is the most common form of cancer in the UK, with over 40 000 new cases diagnosed each year.
The HSE advises that outdoor workers follow the six-point code:
- Skin should be kept covered. Clothing forms a barrier to the ultraviolet rays ;
- A hat should be worn – with a brim or a flap that covers the ears and the back of the neck, as these are areas which can easily get sun burnt;
- Shade should be sought whenever possible, e.g. during work breaks and at lunch time;
- A sunscreen of at least sun protection factor 15 (SPF15) should be used on any exposed skin;
- Plenty of water should be consumed to avoid dehydration; and
- Skin should be regularly checked for unusual moles or spots. A doctor should be consulted if anything is found that is changing in shape, size or colour, itching or bleeding.
