The reference level for exposure of a person to radioactive substances resulting from a radiological emergency is set at 20 mSv effective dose over the year following the end of the radiological emergency.
This reference level is re-evaluated each year in order to eventually reach 1 mSv in effective dose over one year, added to the level of radioactivity existing prior to the radiological emergency.
The representative of the State in the département takes account of the reference level when deciding to implement lasting measures to protect the population and reduce their exposure as low as reasonably possible. In particular, he may initiate actions to clean up contaminated areas.