In off-site emergency management a distinction is made between short-term, medium-term and long-term measures.

Short-term measures include, in particular, disaster control measures aimed at immediate emergency response. Its main objectives include:

  • to prevent the deterministic effects of acute high doses of ionising radiation and
  • to reduce the risk of stochastic effects.

A deterministic effect is damage incurred over a short time period through the exposure of tissues and organs to ionising radiation, resulting in characteristic clinical symptoms. Deterministic effects occur above a specific dose threshold.

Absorbed doseEffects on the human body
> 100 mGy
  • Organs such as the gonads (testes, ovaries) and bone marrow display initial functional limitations. 
  • The human foetus may develop deformities. 
> 1000 mGy
  • Human organs and tissues display clinically relevant changes.
  • Acute radiation syndrome occurs as a severe deterministic effect following brief whole body irradiation or partial exposure of much of the body.

With stochastic effects of ionising radiation, there is an increased probability that cancer or leukaemia, for example, will occur over time (years or decades later). According to current scientific knowledge, there is no threshold dose below which it is relatively certain that an adverse stochastic effect cannot occur. The probability of the effects increases with dose, but the severity of the effects is independent of the absorbed dose.

Medium-term and long-term measures include all the measures taken to minimise stochastic effects i.e. to keep the risks to the public below the intervention reference levels for disaster control. They include measures which follow on, spatially or temporally, from short-term disaster control measures in the vicinity of a facility where an accident has occurred. An example of this would be setting maximum permitted levels of radioactive contamination in food.

Short-term, medium-term and long-term measures supplement one another and need to be coordinated.