Radiological and Nuclear Incidents

Guidance for Responding to Radiological and Nuclear Incidents

This fact sheet provides guidance on what to do in the event of three types of nuclear/radiological events: dispersal of radioactive materials by a radiation dispersal device (RDD); detonation of a nuclear weapon; and an accidental/intentional nuclear power plant release. Taking the correct actions before and after an incident could significantly increase the chance of survival and reduce the medical consequences of the incident.


Although the information in this circular is provided for general information, the Department of State is not the lead government agency on radiological or nuclear incidents and cannot make any warranty regarding the information. At present, there is no one government agency that has taken the lead responding to nuclear or radiological incidents. As always, we will share with U.S. citizens any information we receive regarding threats to their safety.


Radiological Dispersal Devices

Radiological dispersal devices (RDDs) may be improvised explosive devices, also called "dirty bombs," but can include non-explosive devices that could be used to spread radioactive material as well. It is not necessary to use a bomb to disperse radioactive materials; these materials come in solids, liquids, and powdered forms, which can be spread covertly. The major impact of a dirty bomb is produced by the blast and the fear and panic that will ensue. RDDs are not very effective means for exposing large numbers of people to lethal doses of radiation.

Unlike a nuclear detonation, RDDs are likely to affect relatively small areas, and the most effective protection is to leave the affected area. Do not shelter-in place. If there is a possibility that the suspected device has explosives attached, it should be treated as a bomb. Do not reenter the contaminated area. Individuals evacuating a contaminated area should be decontaminated immediately and seek medical attention. Decontamination is most easily achieved by simply taking a shower, washing effectively, and changing into clean clothing.

Do not use Potassium Iodide (KI). Unfortunately radioactive materials can range from conventional weapons isotopes, to materials used in medical and industrial processes. KI should be administered only by health professionals and only if the radiation contamination is identified as being radioactive iodine. With the radioactive isotope unknown, KI administration is not recommended. Potassium iodide, without the presence of radioactive iodine, will cause negative health effects in certain groups of people. Radioactive iodine is very difficult to obtain, and is not considered a likely isotope to be used in an RDD incident.


Food Safety

As noted above, radioactive particles in food or water may be harmful if consumed. Food in tightly covered containers (cans, bottles, plastic, and boxes) will be safe to eat or drink if you dust or wipe off the containers. Be sure to wash fruit and vegetables and peel them carefully. Water will be safe if it is in covered containers, or if it has come from covered wells, or from undamaged and uncontaminated water systems.

If exposure to an RDD is suspected, seek medical assistance as soon as possible. Radioactivity from an area of fallout may produce illness in the unprotected individual immediately or after a few days. Radiation illness cannot be spread to other people. A combination of loss of hair, loss of appetite, increasing paleness, weakness, diarrhea, sore throat, bleeding gums and easy bruising indicate that the individual requires medical attention for exposure to radiation.


Nuclear Detonations

A nuclear detonation, with the resultant radiation, blast and thermal injuries, would be a catastrophic event. In addition to the nuclear fallout and associated damage to structures, a nuclear detonation will severely disrupt civil authority and infrastructure, complicating evacuations and re-establishment of normal operations within a country. All nuclear detonations have four factors in common: blast effect, thermal radiation, ionizing radiation, and electro-magnetic pulse.

Blast effects are dynamic winds and static overpressure. Dynamic winds are much like those experienced during a hurricane, although more localized and of higher velocity. In addition to blowing down structures, these winds can pick up debris that can damage other objects and persons due to their high velocity. Static overpressure is the increase in pressure when the blast wave surrounds an object. Static overpressure has a crushing effect on hollow objects and can crush buildings and damage internal organs. A 10-kiloton nuclear surface detonation will create a crater 600 feet in diameter, 170 feet deep, and have serious destructive blast effects for 1.2 miles.

Thermal radiation is the intense heat and light released by a nuclear burst. It can cause temporary or permanent blindness, burns and fires. Burns can be related to the blast (flash burns) or a result of secondary fires. A 10-kiloton surface nuclear detonation will generate serious skin burns for up to about 1.3 miles. Severe eye injury leading to blindness can occur from looking directly at the blast many miles beyond the range at which all other immediate effects occur.

Ionizing radiation is the radiation produced by a nuclear detonation. Outside of the detonation zone this is the most critical issue for survivors. Initially, there is an intense burst of gamma and neutron radiation that travels outward from ground zero with the thermal radiation. Soil below the fireball can also become radioactive. The material from the bomb that is not consumed in the explosion, as well as debris incorporated into the fireball and made radioactive, will return to earth as radioactive fallout. This fallout will emit gamma, alpha, and beta radiation. Amounts of radiation experienced with a detonation depend on the method of detonation (air, surface or subsurface), what the components of the bomb are, and what type of bomb it is: fission (explosion and radiation) or fission-fusion (an initial nuclear explosive component that triggers a bigger reaction/explosion and radiation release). Environmental conditions, weather patterns, rain, wind, and terrain can greatly influence the effects of the blast and the resultant fallout. Electro-magnetic pulse (EMP) is another effect of an aboveground or air nuclear detonation. This intense magnetic field has the ability to adversely affect or destroy unshielded electronic equipment by burning/fusing the internal circuits. A burst of EMP will disrupt and destroy communications equipment. EMP affects all modern electronic components. A strong EMP will nullify radio, television, cell phone, and telephone communications. Ground burst detonations may generate EMP up to 2 miles from the point of detonation.


Preparation for and Response to Nuclear Detonations

The two most important issues for survivors of a nuclear detonation are shelter and decontamination. The importance of sheltering in place, preferably inside a sealed room, for at least the first 48 hours after a nuclear detonation cannot be over-emphasized. The most lethal threat to persons in a contaminated area after a blast is exposure to and ingestion of radioactive fallout. Focus planning efforts on preparing shelter and supplies, and on understanding and providing for decontamination.

Provision should be made for some form of immediate shelter. It is essential to put as much physical mass between yourself, the blast and the resultant radiation as possible. Identify locations in your residence and place of work which offer the greatest protection. Ideal places are basements and other reinforced underground space. As an alternative, windowless interior spaces should be considered, above ground to protect from surface radiation. A windowless room on a mid-level floor of a high-rise affords the most protection from radioactive fallout on the ground and on roof surfaces.

In the event of a nuclear explosion, seek shelter immediately in a space that offers the most protection. It is anticipated sheltering will be needed for no less than 48 hours. The radioactivity in fallout weakens rapidly in the first hours after an explosion. This weakening is called "decay". After seven hours, fallout has lost about 90% of the strength it had one hour after the explosion. After two days it has lost 99%; in two weeks 99.9% of its strength is gone. Nevertheless, if the radiation at the beginning were high enough, the remaining 0.1% could be dangerous. Ideally, plan to stay in the shelter until radiation has been measured and the appropriate authorities have announced that it is safe to come out. Radiation effects are cumulative; the effects depend on level and duration of exposure.

Ensure emergency supplies are ready. You should prepare to remain sheltered for at least 48 hours, but if may be necessary to remain sheltered for up to 14 days and, therefore, have 14 days of food, water, medicines, first aid and personal supplies on-hand. Have a battery-powered radio available in order to monitor emergency frequencies often.

Prepare to decontaminate individuals exposed to fallout  The objective of decontamination is to remove the particles of radioactive dirt or dust that have come in contact with the skin or clothes. Potentially contaminated clothing and other items should be removed or discarded prior to entering the shelter area. Simply taking a shower, washing effectively, and changing into clean clothes will generally decontaminate effectively. Bleach should not be used to decontaminate, and never used directly on skin or to scrub skin or wounds. Ideally, the water used for all purposes, including hygiene, should be stockpiled from safe sources and placed in sealed containers. The water used for decontamination must be contained and covered or drained outside of the shelter area to avoid shelter contamination.

In a nuclear detonation, medical resources will be quickly overwhelmed. Traumatic injuries and burns are the most immediate consequences of a nuclear detonation and require conventional medical and surgical care. Critical points to remember are: The injured are not radioactive and pose no danger to first responders; stabilizing injuries are the first priority, decontamination comes second; injured personnel should have wounds decontaminated by medically trained personnel if possible. Vigorous scrubbing disrupts the skin, potentially embedding radioactive particles into tissue.

Radiation sickness may also follow. Nausea and general weakness are the immediate effects of significant radiation exposure. Delayed effects can appear days to weeks later and may involve the central nervous, immune, and gastro-intestinal systems. Generally, no specific therapy for radiation exposure is immediately necessary, beyond routine supportive care for victims. There are few drugs available to counteract radiation from a nuclear detonation. These require sophisticated medical oversight and hospitalization, which are seldom available in an emergency setting, and will most likely be only available when evacuation is possible.

Food Safety  Radioactive particles in food or water may be harmful if consumed. Food in tightly covered containers (cans, bottles, plastic, and boxes) is safe to consume if the containers are dusted or wiped off. Fruit and vegetables should be washed and peeled carefully. Water will generally be safe if it is in covered containers or has come from covered wells or undamaged/uncontaminated water systems. Reverse-osmosis water filtration systems will remove fallout contamination. If sheltering extends beyond 14 days, animal products, including milk and meat should not be consumed if they are from sources that may have been fed contaminated grains or grasses. Fresh fruits and vegetables picked from contaminated soils should not be consumed.

Antidotes such as potassium iodide (KI) are not/not helpful in a nuclear detonation. KI is useful in response to a nuclear reactor mishap, where radioactive iodine release is a hazard. Radioactive iodine is not significantly present after a nuclear detonation, so KI is not useful in these circumstances.


Nuclear Power Plant Release

In general, the shelter preparedness and response recommendations for responding to a nuclear detonation also apply to the situation of an accidental or intentional release of radioactive material from a nuclear power plant with exceptions as noted below.

Accidents may occur at nuclear power plants resulting in the release of a plume of radioactive particles into the atmosphere that can create fallout. Due to differences in nuclear fuels and the resultant reactions that take place when a reactor accident occurs, the radioactive elements of this fallout (called isotopes) from a nuclear power plant accident are not the same as those found in fallout from the detonation of a nuclear device.

Use of potassium iodide: KI is an antidote almost exclusively used in the aftermath of reactor incidents. KI counters the effects of radioactive iodine internally ingested or inhaled in fallout.

Shelter in Place: Even though exposures are more localized, shelter should be prepared as noted above (nuclear detonation). Seek shelter unless other instructions for evacuation are given.

Decontamination in the aftermath of a nuclear reactor incident will be required in the immediate vicinity and downwind of the mishap. Critical health and safety issues include eliminating exposure to isotopes that have contaminated the food and water chain. It is critical to avoid vegetable and fruit grown in contaminated soil or products from animals fed on grass or grains from contaminated soil. Individuals in areas deemed not contaminated do not need to take any protective measures except avoiding food exported from contaminated areas.