Occupational radiation exposure: health effects, limits and monitoring

The HSE explains that every day in the UK a wide range of radiation types are used in industrial, medical, research and communications applications. Radiation is generally classed as ionising or non-ionising. Ionising radiation, which has more energy, includes X-rays, gamma rays and particle radiation from X-ray sets or radioactive substances. It is used in medical exposures, industrial radiography and process-control gauges, and it also comes from naturally occurring radioactive substances, including radon gas.

Non-ionising radiation includes radiofrequency and microwaves, infra-red from very hot sources, ultraviolet from welding or the sun, and visible light from high-intensity sources such as lasers. This page concentrates on ionising radiation, since that is what people usually mean by radiation exposure at work, while noting that the HSE covers both.

Occupational exposure is not the same as accidental or environmental exposure. In regulated work, doses are expected, planned and monitored, and the law requires employers to keep them as low as is reasonably practicable and below the dose limits.

The HSE says ionising radiation can cause dermatitis, burns, cell damage, cataracts and changes to blood. Exposure to ionising and UV radiation can damage DNA and can cause health effects, such as cancer, later in life. The risks are small for low levels of exposure, but exposure to high levels can cause acute effects such as burns, and tissue and organ damage.

UKHSA adds that the health effects of ionising radiation depend on the dose received. Low doses increase the risk of cancer later in life, while very high doses act like a poison and can be fatal, though the risks to health are in general low and ionising radiation is widely used in cancer therapy. UKHSA's dose comparison table gives, for scale, about 100 mSv as the level at which changes in blood cells can be readily observed and about 1,000 mSv as the level at which acute effects including nausea and a reduction in white blood cell count occur.

For non-ionising radiation the HSE lists skin burns and cataracts from infra-red, burns, skin cancer, conjunctivitis and arc eye from UV, heating of exposed body parts from microwaves and radiofrequencies, and permanent, severe damage to the eyes and skin from lasers.

UKHSA calculates that people in the UK are exposed on average to about 2.6 millisieverts (mSv) of radiation a year. The largest share is naturally occurring radiation in homes and workplaces, notably radon gas, with contributions from food and medical exposures. The same page gives these comparison values.

The HSE says the fundamental requirement is for employers to reduce all exposure to ionising radiations to as low a level as possible, below the dose limits. Limits are defined in Schedule 3 of the Ionising Radiations Regulations 2017, with different limits for adult employees, trainees aged 16 to 18 and members of the public, and it is an offence to exceed them. Employers must identify sources, assess risk, notify, register or seek consent from the HSE depending on the work, and, when working with ionising radiation, obtain advice from a radiation protection adviser, which is a legal requirement.

An employer must classify an employee who is likely to receive an effective dose of more than 6 mSv a year, an equivalent dose of more than 15 mSv a year to the lens of the eye, or more than 150 mSv a year to the skin or extremities. Employees can only be classified if aged 18 or over. A classified person must be told, have their dose assessed and recorded and be certified fit to work with ionising radiation by an appointed doctor or employment medical adviser, which is medical surveillance. Controlled areas are designated where special procedures apply, and entry is restricted.

The HSE says it is in your interest and that of your baby to tell your employer as soon as you know you are pregnant, so that protection measures can be changed and additional dose constraints applied. You are not legally required to tell your employer and can choose to keep it private, but if your employer is unaware they may be unable to act. The HSE has separate guidelines for expectant or breastfeeding mothers.

Start with your employer or occupational health service, who hold dose records. The HSE says employers must assess and record doses for classified persons, and where you work for more than one employer, the employers should cooperate to ensure relevant exposure information is shared. The radiation protection adviser can explain how your doses were assessed.

If you have symptoms, see a GP and mention your work. For sudden illness after a known high exposure, such as nausea, burns or feeling very unwell, seek urgent medical help through NHS 111, or 999 in an emergency. Keeping exposure low, following the controls in place and keeping dose records are the main protections.

The HSE notes that radon gas is naturally occurring and may be present in a workplace even if you do not do any other work with radiation, and that employers should consider it in their risk assessments. Radon is more likely to accumulate in ground-floor rooms, and the HSE example describes an employer using the UKradon website to check whether premises were in a radon-affected area before carrying out an assessment.