In the event of a situation of long-term exposure to radioactive substances resulting from a radiological emergency, the representative of the State in the département, after obtaining the opinion of the Nuclear Safety Authority and the Regional Health Agency, defines a strategy for the management of contaminated areas, for the protection of people and the environment, based on the application of the optimisation principle defined in 2° of Article L. 1333-2 and taking into account the reference level defined in Article R. 1333-93.