This Directive applies to all practices involving a risk from ionizing radiation emanating from an artificial source or from a natural radiation source in cases where natural radionuclides are or have been processed in view of their radioactive, fissile or fertile properties. Such practices include in particular the production, processing, handling, use, holding, storage, transport, import to and export from the Community and disposal of radioactive substances. On the other side, this Directive shall not apply to exposure to radon in dwellings or to the natural level of radiation, i.e. to radionuclides contained in the human body, to cosmic radiation prevailing at ground level or to aboveground exposure to radionuclides present in the undisturbed earth's crust. The above-mentioned practices may be carried out only upon prior authorization and must be reported to the competent authorities. Title III of the Directive is entirely devoted to such reporting and authorization. Article 5 concerns authorization and clearance for disposal, recycling or reuse of radioactive substances or materials containing radioactive substances. Further, Title IV deals with justification, optimization and dose limitation for practices. Title V lays down rules relating to estimation of effective dose. Title IX regulates with details the interventions to be undertaken in case of radiological emergencies.