Radiological Dispersal Device

NARAC technical plots show the areas that may warrant evacuation or sheltering of the general population, long-term relocation, emergency worker safety measures, or actions to address contamination of agricultural crops. Health effects may result from inhalation of airborne radiological material, external radiation from immersion in the airborne plume, and/or exposure to ground shine radiation from material that has deposited on the ground.


Protective Action Guide (PAGs) levels are the projected doses at which specific protective actions to reduce or avoid that dose are warranted.

PAG dose thresholds are based on federal EPA/DHS guidelines.

Exposure calculations assume that individuals remain outdoors in the same location throughout the plume passage.


Manual of Protective Action Guides and Protective Actions for Nuclear Incidents (EPA 400-R-92-001, May 1992).

"Protective Action Guides for Radiological Dispersal Device (RDD) and Improvised Nuclear Device (IND) Incidents", (Federal Register, Vol. 71, No. 1, Jan. 3, 2006, p. 174).