/Docs/G/Org-IAEA-Safety-GSR3-CmA/Sec/5_Existing_0.md
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The requirements for existing exposure situations in Section 5 apply to:
  1. Exposure due to contamination of areas by residual radioactive material deriving from:
    1. Past activities that were never subject to regulatory control or that were subject to regulatory control but not in accordance with the requirements of these Standards;
    2. A nuclear or radiological emergency, after an emergency has been declared to be ended (as required in para. 4.20).
  2. Exposure due to commodities, including food, feed, drinking water and construction materials, that incorporate radionuclides deriving from residual radioactive material as stated in para. 5.1(a).
  3. Exposure due to natural sources, including:
    1. 222Rn and its progeny and 220Rn and its progeny, in workplaces other than those workplaces for which exposure due to other radionuclides in the uranium decay chain or the thorium decay chain is controlled as a planned exposure situation, in dwellings and in other buildings with high occupancy factors for members of the public;
    2. Radionuclides of natural origin, regardless of activity concentration, in commodities, including food, feed, drinking water, agricultural fertilizer and soil amendments, and construction materials, and residual radioactive material in the environment;
    3. Materials, other than those stated in (c)(ii) above, in which the activity concentration of no radionuclide in either the uranium decay chain or the thorium decay chain exceeds 1 Bq/g and the activity concentration of 40K does not exceed 10 Bq/g;
    4. Exposure of aircrew and space crew to cosmic radiation.