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Damage Zones, Radiations Zones and Likely Rescue Activities After a Nuclear Detonation: Table 1, 2

Zone name Damage seen Likely rescue activities
Severe Damage Zone
(SD Zone)
  • Few if any buildings will be standing or structurally sound.
  • Rubble in streets will make streets impassable, and hindering prompt rescue.
  • Survivors may exist in some subterranean parking garages, subway tunnels.
  • Zone will have very high radiation levels from prompt and residual origin, hampering rescue efforts.
  • Responses here should not be attempted until radiation dose rates have dropped substantially (days), and MD zone responses have significantly advanced.
  • Rescuers should enter this area with great caution, only to rescue known survivors.
  • Any response missions here must be justified and minimize responder risks based on risk/benefit considerations.
  • If responders enter here, they will use personal protective equipment and appropriate dose monitors.
  • Only short entries, if any, will be safe due to high radiation levels.
Moderate Damage Zone
(MD Zone)
  • When rescuers enter MD zone from LD zone, visual cues will include buildings with severe structural damage, blown out interiors, blown over telephone poles and street lights, downed utility lines, overturned cars, caved roofs, some collapse buildings and fires, crashed and overturned vehicles, blocked streets, broken water, gas, electrical and communication lines.
  • Sturdier buildings (e.g., reinforced concrete) may remain standing, but less sturdy structures will be heavily damaged or destroyed.
  • Will contain extremely dangerous levels of fallout.
  • This zone will have the highest proportion of "survivable victims" who require urgent medical treatment.
  • Urban search and rescue will be most efficient and effective in non-radiologically contaminated areas of this zone.
  • Response activities in this zone will have to plan for elevated radiation levels, unstable buildings, downed power lines, ruptured gas lines, hazardous chemicals, sharp objects, broken glass, fires.
  • Rescues here will focus on victims with urgent needs who are unable to self-evacuate.
  • Response activities here will focus of early life-saving operations and medical triage.
  • Minimizing radiation dose to victims and responders will be a key goal.
  • Responders will use personal protective equipment and appropriate dose monitors.
  • Worker Exposure Guidelines should inform responder activities in this zone.
Light Damage Zone
(LD Zone)
  • Damage caused mainly by blast shocks, which can rebound multiple times off buildings, ground, and even the atmosphere.
  • Damage this area will be highly variable.
  • Glass breakage will be prominent.
  • As responders moves progressively inward to ward MD zone , windows and doors will be blown in and gutters, window shutters, roofs and lightly constructed buildings will have increasing damage.
  • Litter and rubble will increase moving toward ground zero as will the number of stalled and crashed cars, making it difficult for emergency vehicles to pass through.
  • Most of the injuries in this zone are not expected to be life threatening,
  • Injuries are expected to be associated with flying glass and debris from the blast wave and traffic accidents.
  • Low benefit of responders rescuing ambulatory survivors in this zone, as they are less severely injured, and can move out to medical care and assembly shelters on their own.
  • Responders here should focus medical attention in the only on severe injuries and should encourage and direct individuals to shelter in safe locations to expedite access to severely injured individuals.
  • Responders will use personal protective equipment and appropriate dose monitors.
  • Worker Exposure Guidelines should inform responder activities in this zone.
Dangerous Fallout Zone

(> 10 R/hour at the outer perimeter of this zone. Within the zone, the levels will be variable and higher closer to ground zero. Zone boundary footprint will increase initially but shrink quickly as radioactivity decays. )
  • Fallout will be extensive longitudinally along the path of upper level winds.
  • May overlap outer edge of Light or Moderate Damage Zone.
  • The most hazardous fallout particles are readily visible as fine sand-sized grains, but the absence of visible fallout should not suggest the lack of radiation.
  • Locally, fallout may exhibit significant spread from lower winds.
  • Fallout footprint with highest levels of radiation close in will be defined within 1-2 hours; fallout immediately hazardous to the public and emergency responders will descent to ground within about 24 hours
  • Visible fallout provides strong evidence of dangerous radiation levels, but exact levels must be measured.
  • The highest hazard from fallout occurs within the first 4-6 hours, but dangerous levels will persist long after that.
  • DF zone may extend 10-20 miles downwind in some cases, but it will quickly and steadily shrink in size as fallout decays.
  • Exposure rates in this zone can produce acute radiation injury and may be lethal, so actions taken in this zone should be restricted to time-sensitive, mission-critical activities, such as life-saving.
  • Most important mission in DF zone is communicating protective action orders to the public: sheltering in place, evacuation when and where it becomes safe after radiation levels from fallout drop significantly.
  • Responders will use personal protective equipment and appropriate dose monitors.
  • Worker Exposure Guidelines should inform responder activities in this zone.
10mR/hour boundary
(named "Hot zone" by NCRP2)

(10 mR/hour at outer perimeter of this zone. Within the zone, the levels will be variable and higher closer to ground zero. Zone boundary footprint will increase initially but shrink quickly as radioactivity decays. )
  • Can reach several hundred miles from ground zero for some detonations.
  • Zone footprint will quickly and steadily shrink as fallout decays.
  • The use of the term "hot zone" is recommended by NCRP but not by all response groups. Nonetheless, the concept of the 10mR/hour line is generally accepted by most experts as useful for organizing response activities.
  • Responders will use personal protective equipment and appropriate dose monitors.
  • Worker Exposure Guidelines should inform responder activities in this zone.

1 Planning Guidance for Response to a Nuclear Detonation, Second edition, 6/2010 (PDF - 2.62 MB) (National Security Staff, Interagency Policy Coordination Subcommittee for Preparedness & Response to Radiological and Nuclear Threats)
2 Responding to a Radiological or Nuclear Terrorism Incident: A Guide for Decision Makers (PDF - 1.61 MB) (NCRP Report No. 165), National Council on Radiation Protection and Measurements, Bethesda, MD, January 2010.

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