The Health and Safety Executive for Northern Ireland (HSENI) is one of a number of public bodies which regulate work that causes or could cause radiation exposure of workers, the public or both. HSENI’s inspectors advise, inspect, investigate and enforce in a flexible and proportionate way so that radiation exposure of employees and others, arising from work activities, is adequately controlled.

Ionising radiation

Ionising radiations occurs as either electromagnetic rays (such as X-rays and gamma rays) or particles (such as alpha and beta particles). It occurs naturally (for example from the radioactive decay of natural radioactive substances such as radon gas and its decay products) but can also be produced artificially. People can be exposed externally, to radiation from a radioactive material or a generator such as an X-ray set, or internally, by inhaling or ingesting radioactive substances. Wounds that become contaminated by radioactive material can also cause radioactive exposure.

For more information on ionising radiation view the 'ionising radiation' webpage at the following link:


Radon is a naturally occurring radioactive gas emanating from many naturally occurring rocks and soils and can build up in indoor workplaces.

Radon and the radioactive elements formed during its decay can be inhaled and enter the lungs causing cell damage, which can lead to lung cancer. 

Radon contributes by far the largest component of background radiation dose received by the UK population and significant exposures are possible in workplaces.

Non-ionising radiation

Non-ionising radiation (NIR) is the term used to describe the part of the electromagnetic spectrum covering two main regions, namely optical radiation (ultraviolet (UV), visible and infrared) and electromagnetic fields (EMFs) (power frequencies, microwaves and radio frequencies).

Electromagnetic Fields (EMF's)

Electromagnetic fields (EMFs) arise whenever electrical energy is used. So for example, EMFs arise in our home from electrical appliances in the kitchen, from work processes such as radiofrequency heating and drying and in the world at large from radio, TV and Telecoms broadcasting masts and security detection devices.

For more information on electromagnetic fields view the 'Electromagnetic fields' webpage at the following link:


Key legislation

Please note that these links are to the original legislation, visitors should verify for themselves whether legislation is in operation or whether it has been amended or repealed by subsequent legislation.