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Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
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5
PROTECTIVE MEASURES

This chapter describes accident classifications and the sequences of events for responding to an incident at a commercial nuclear power reactor. The roles of local, state, and federal agencies are detailed; they are influenced by the severity of the incident. Detailed plans are in place in the communities near commercial nuclear power reactors that address incidents that proceed from a notification of unusual event all the way through a general emergency. Sheltering, evacuation, food interdiction, and so on are reviewed, in addition to postincident response measures. For cases when administration of KI is required, details are provided regarding its appropriate preparation. The chapter also discusses concerns about the various pharmaceutical issues surrounding KI, such as ease of use, dosage forms for children and infants, stability of KI, and non-FDA-approved formulations.

In the United States, public health and safety are state responsibilities. However, states generally have delegated some

Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
×

authority to respond to incidents to local public officials and local responders. Local responders are generally the first to arrive at the scene of an accident or incident and have the best knowledge of local conditions that might affect response decisions. If the situation overwhelms the response capability of local responders, state and then federal resources may be called on to assist. In general, incidents that overwhelm local resources affect large geographic areas or large populations.

States have developed response plans to guide them through the decision-making process in connection with an incident to mitigate the consequences of large events. The emergency-preparedness plans include predetermined actions related to credible scenarios that enable quick responses to ensure public safety with limited initial information. Emergency-response plans take into consideration such items as general types of incidents, general traffic conditions, location of different types of fixed facilities, predominant weather for different times of year, population densities, available state and local resources, prearranged contracts for services with private industries, and other relevant observations. Planning allows for quick decision-making in the face of sparse information to ensure public health and safety.

Emergency preparedness for NPP incidents is a cooperative effort involving the NPP facility, local government, county government, state government, and the federal government. Since the emergency-preparedness plans must be capable of initially addressing several possible incidents, they must be based on simple and consistent assessment methodologies, and the agencies involved must be capable of implementing their assigned actions. To ensure that plans developed on the local, county, and state level will protect public health and safety, the US Nuclear Regulatory Commission and the Federal Emergency Management Agency (FEMA) evaluate emergency preparedness at and around NPPs. Evaluation takes place regularly to ensure that adequate protective measures will be taken in the event of a NPP incident.

Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
×

Accident Classifications

The US Nuclear Regulatory Commission has developed four action levels to address how agencies should respond to NPPs incidents that could lead to serious consequences. The actions taken by state and local agencies in response to a notification of an incident are graduated from a notification to be aware of a situation to full emergency response actions. This graduated response ensures that emergency response preparations can be taken in advance of a severe accident if a minor situation worsens. The four accident classifications are: Notification of Unusual Event, Alert, Site Area Emergency, and General Emergency, and are described below.

Notification of Unusual Event

This classification is used to describe events that indicate a potential degradation of safety at a NPP. Offsite response or monitoring is not expected unless further degradation of safety systems occurs. Its purpose is to assure that the first steps in response preparations have been carried out and to bring state and local response organizations to a state of readiness. During this classification authorities provide fire or security assistance as requested and standby for additional information.

Alert

Events are in process or have occurred that indicate an actual or potential substantial degradation of safety at a plant. Any release of radioactive material is expected to be limited to small fractions of the EPA Protective Action Guideline (PAG) Exposure Levels. It assures that emergency personnel are readily available to respond if the situation becomes more serious or to perform confirmatory radiation monitoring if required and provide state and local authorities current status information. In addition to the assistance requested for an unusual event, authorities augment emergency response resources, provide confirmatory offsite radiation monitoring or ingestion

Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
×

pathway dose projections as appropriate, and standby for additional information.

Site Area Emergency

During this emergency classification events are in process or have occurred that involve actual or likely major failure of plant functions needed for protection of the public. Radioactive material releases are not expected to exceed EPA Protective Action Guideline Exposure Levels except near the site boundary. It assures that state and local authorities have manned emergency operation centers, dispatched monitoring teams, activated personnel required for evacuation, placed reception centers on standby, and are capable of providing the public with updates of the situation. In addition to the activities taken at an Alert, authorities activate public notification systems as appropriate, provide the public with periodic updates on emergency status, dispatch emergency response personnel to near-site duty stations, provide offsite monitoring results to the licensee and other government agencies to jointly assess findings, consider placing milk producing animals within the EPZ on stored feed, and standby for additional information.

General Emergency

This is the most serious emergency classification. Events are in process or have occurred that involve actual or imminent substantial reactor core degradation with a potential loss of containment integrity resulting in a need for protection of the public. Radioactive material releases are expected to exceed EPA Protective Action Guideline exposure levels. It assures that state and local authorities initiate predetermined protective actions, continuously assess information from a nuclear power plant and offsite measurements, and are capable of providing the public with updates of the situation. In addition to the activities taken at a Site Area Emergency, authorities activate the emergency alert systems to immediately notify the public of the emergency status, implement Protective Action Recommendations, continuously assess information

Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
×

from the licensee and offsite monitoring with regard to changes to protective actions already initiated for the public, mobilize evacuation resources, activate reception centers, and maintain general emergency status until closeout or reduction of emergency class.

Emergency Workers

Radiological Emergency Response Plans (RERP) must address not only public health and safety, but also the health and safety of offsite emergency workers, those who are not employees or contractors directly associated with the NPP. The federal government cannot specify the protective policies that must be in place for this population, but the certification process for facilities requires that an acceptable plan be in place.

Emergency workers who might be exposed to radiation while performing assigned duties include law-enforcement officers, firefighters, emergency medical personnel, and other responders performing activities in areas with increased radiation fields. While the overall objective is to minimize individuals’ radiation exposure to the maximum extent possible, protective actions for the public and dose limits for emergency workers are based on different assumptions. Protective actions for the public compare the risks to people posed by radiation exposure with the risks associated with specific protective actions to minimize the total risk. Emergency workers, however, are allowed to receive a certain level of radiation exposure to protect the public and property. The planning assumption for emergency workers compares the risk posed by radiation exposure with the overall benefits to society associated with specific activities (USEPA, 1992).

Existing emergency preparedness plans for NPP incidents address the use of KI by emergency workers. Emergency workers are authorized to receive radiation exposure exceeding the dose limits for the general public during an incident to protect the public and property, and they accept the risk associated with it. Because there may be a need for extended activity by emergency workers in a radiation field that could result in exposure to various radionuclides in various concentrations, minimizing exposure to even a single

Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
×

radionuclide is beneficial. Therefore, existing plans already provide guidance on the administration of KI to emergency workers to reduce their risk associated with radioactive iodine. On the other hand, guidance for the administration of KI to the general public is still under development in many states (see Chapter 6). Traditionally, KI for emergency workers has been distributed in packages that provide a daily dosage for a 2-week period. This continued dosage of KI would not be appropriate for the general public. As will be described later in this chapter, protective action for the public minimizes the total risk from all sources. The general public should be given KI only if this action is expected to result in a minimization of the total risk.

Strategies for the General Public

Radiological Emergency Response Plans for NPP incidents are designed to simplify the decision-making process for local responsible authorities, to avoid radiation exposure and perform lifesaving activities. The plans must be specific enough to provide a sound basis on which to respond to incidents without unnecessarily depleting available resources. They must be general enough to be applicable to a variety of situations so that only workable and useful actions are considered during an emergency. Accordingly, emergency-response plans address the consequences of an incident, both in nature and in degree, but not its cause. That allows the development of specific actions that can be taken by response organizations during the decision-making process for an unknown future event, based on what is known at each site about the potential consequences, local conditions, and release characteristics of the spectrum of accidents.

Phases of Emergency Response

Response plans are bound by the timing of response actions to incident consequences and play a significant role when resources are

Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
×

deployed. In general, all nuclear power plant incidents follow a common sequence of events characterized as the early, intermediate, and late phases. The Manual of Protective Action Guides and Protective Actions for Nuclear Incidents, Report No. 400-R-92-001, U.S. Environmental Protection Agency, 1992 published by the US Environmental Protection Agency, describes each phase as follows:

The early phase (also referred to as the emergency phase or plume phase) is the period at the beginning of a nuclear incident when immediate decisions for effective use of protective actions are required and must therefore usually be based primarily on the status of the nuclear facility and the prognosis for worsening conditions. This phase may last from hours to days.”

The intermediate phase (also referred to as the ingestion phase) is the period beginning after the source and releases have been brought under control and reliable environmental measurements are available for use as decisions on additional protective actions. This phase may overlap the early and late phase and may last from weeks to many months.”

The late phase (also referred to as the recovery phase) is the period beginning when recovery action designed to reduce radiation levels in the environment to acceptable levels for unrestricted use is commenced, and ending when all recovery actions have been completed. This phase may extend from months to years.” (USEPA, 1992).

In the United States, the Nuclear Regulatory Commission and FEMA use NUREG 0654, Criteria for Preparation and Evaluation of Radiological Emergency Response Plans and Preparedness in Support of Nuclear Plants, to evaluate state and local emergency response plans.

Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
×

Early Phase Planning

NUREG 0654 contains the guidance used by the federal government to evaluate emergency-response plans developed by state and local governments. The predominant route of exposure that a planning agency must consider in developing a radiological emergency response plan for the early phase is from the emitted plume, i.e. plume-exposure pathway. NUREG 0654 states:

“Plume exposure pathway—The principal exposure sources from this pathway are: 1) whole body external exposure to gamma radiation from the plume and from deposited material; and 2) inhalation exposure from the passing radioactive plume. The duration of the release leading to potential exposure could range from one-hour to days.” (USNRC, 1980).

Limits on the available resources dictate that the size of the planning area, i.e. emergency planning zone (EPZ), needs to be considered. The EPZ is determined by the actions needed for emergency response, the source term for the radiation, the time required to respond, and the consequences of a credible event. The Manual of Protective Action Guides and Protective Actions for Nuclear Incidents Report No. 400-R-92-001, U.S. Environmental Protection Agency, 1992 discusses guidance on the relationship between the acceptable level of radiation to which the general public can be exposed and recommended actions to be taken. The Nuclear Regulatory Commission has determined the size of an early phase or plume phase EPZ (USNRC, 1980). NUREG 0654 states:

“The size (about 10 miles radius) of the plume exposure EPZ was based primarily on the following considerations:

Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
×
  1. projected doses from the traditional design basis accident would not exceed Protective Action Guide levels outside the zone;

  2. projected doses from most core melt sequences would not exceed Protective Action Guide levels outside the zone;

  3. for the worst core melt sequences, immediate life threatening doses would generally not occur outside the zone;

  4. detailed planning within 10 miles would provide a substantial base for expansion of response efforts in the event that this proved necessary.”

“…the plume exposure EPZ is of sufficient size for actions within this zone to provide for substantial reduction in early severe health effects (injuries or deaths) in the event of a worst-case core melt accident.”

The EPZ is established to provide a basis for planning. This includes details on how to advise the population on protective actions, routes for evacuation, and where to evacuate outside the EPZ (reception centers). A specific incident might call for protective actions to be restricted to a small part of the EPZ or require that they be implemented beyond the EPZ as well.

Decision-making during the early phase is difficult. Information about environmental conditions resulting from an incident is generally not available, because there is an inevitable delay in the initiation of a release of radioactive material and plume arrival at a point of interest. The need to make early decisions to protect the public requires that decision-making criteria be identified well in advance. This simplifies the decision making process to ensure that timely measures are taken to protect the public. Accordingly, during the early phase, protective action decisions are based on the status of the NPP and on the prognosis for a worsening of conditions (USEPA, 1992).

Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
×

Because plant conditions are the basis for decision-making, it is likely that evacuation (or sheltering) will begin before a significant radiologic release requiring an offsite response starts. If there is a release, it may not contain radioactive iodine. If evacuation is completed prior to exposure to radioactive iodine or if radioactive iodine is not a component of the plume, there is no need to administer KI.

The presence of radioactive iodine in a plume is usually indicated on plant monitors. With this information and using dose modeling techniques, decision-makers can estimate the radiation dose to the thyroid and take steps to initiate administration of KI in accordance with FDA recommendations about dosages. The public will be advised to take KI through the Emergency Alert System when the projected radiation dose to the thyroid is greater than predetermined PAG. This PAG should be set at a projected radiation dose to the thyroid of 50 mSv (5 rem) for the most vulnerable populations: infants, children, adults under age 40 and pregnant or lactating women of any age. KI should be given only when an exposure or potential exposure to radioactive iodine is suspected. Once a protective action eliminates exposure to radioactive iodine, KI does not provide any benefit. Continued dosing with KI only increases the total risk of rare side effects or adverse effects and therefore dosing should be stopped as soon as exposure is terminated.

Table 5.1 provides a combination of the existing Protective Action Guides (PAG) recommended for evacuation or sheltering for the early phase provided in the Manual of Protective Action Guides and Protective Actions for Nuclear Incidents Report No. 400-R-92-001, U.S. Environmental Protection Agency, 1992 combined with the new FDA guidance for administration of KI to the public published in 2001.

Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
×

Table 5.1 Protective Action Guides for Early Phase of a Nuclear Incident

Protective Action

Protective Action Guide (projected dose)

Comments

Evacuation (or shelteringa)

1-5 rem Total Effective Dose Equivalent (TEDE)

Evacuation (or, for some situations, shelteringa) should normally be initiated at 1 rem. Further Guidance is provided in EPA 400.

Administration of stable iodine

Adults over 40 yrs

>500 remb

Requires approval by a medical official as determined by individual state law.

 

Adults over 18 through 40 years

>10 remb

 

Birth through 18 yrs Pregnant or lactating women

>5 remb

aSheltering may be the preferred protective action when it will provide protection equal to or greater than evacuation, based on consideration of factors such as source term characteristics, temporal or other site-specific conditions (See USEPA, 1992).

bCommitted Dose Equivalent (CDE) to the thyroid from radioiodine (USEPA, 1992, FDA, 2001a).

Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
×

Intermediate Phase Planning

The predominant exposure to radiation during the intermediate phase changes from plume exposure to internal exposure, i.e. via the ingestion exposure pathway. Though the principal radiation exposure changes, emergency actions will continue to monitor external exposure to radiation.

“Ingestion exposure pathway—The principal exposure from this pathway would be from ingestion of contaminated water or food such as milk, fresh vegetables or aquatic foodstuffs. The duration of potential exposure could range in length from hours to months. For the ingestion exposure pathway, the planning effort involves the identification of major exposure pathways from contaminated food and water and the associated control and interdiction points and methods. The ingestion pathway exposures in general would represent a longer term problem, although some early protective actions to minimize subsequent contamination of milk or other supplies should be initiated e.g. remove cows from pasture and put them on stored feed.” (USNRC, 1980).

Limits on the available resources require that the size of this EPZ must be considered as well. The size of the ingestion EPZ is determined by the same basic factors used to determine the plume phase EPZ—namely, the actions needed for emergency response, the source term for the radiation, the time required to respond, and the consequences of credible events. The primary focus is on preventing ingestion of radioactive material. The Manual of Protective Action Guides and Protective Actions for Nuclear Incidents Report No. 400-R-92-001, U.S. Environmental Protection Agency, 1992 and Accidental Radioactive Contamination of Human Food and Animal Feeds: Recommendations for State and Local Agencies, U.S.

Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
×

Department of Health and Human Services, Food and Drug Administration, Center for Devices and Radiological Health, 1998 (FDA, 1998) provide guidance on the relationship between the acceptable level of radiation exposures of the general public and recommended actions that should be taken by public officials and emergency responders. The planning effort for this phase ensures that effective actions can be taken to protect the public from the ingestion of radioactive material in the event of an accident. The Nuclear Regulatory Commission (USNRC, 1980) determined the appropriate size of an intermediate phase EPZ as follows:

“The size of the ingestion exposure EPZ (about 50 miles in radius, which also includes the 10-mile radius plume exposure EPZ) was selected because:

  1. the downwind range within which contamination will generally not exceed the Protective Action Guides is limited to about 50 miles from a power plant because of wind shifts during the release and travel periods;

  2. there may be conversion of atmospheric iodines (i.e. iodine suspended in the atmosphere for long time periods) to chemical forms which do not readily enter the ingestion pathway;

  3. much of any particulate material in the radioactive plume would have been deposited on the ground within about 50 miles from the facility; and

  4. the likelihood of exceeding ingestion pathway protective action guide levels at 50 miles is comparable to the likelihood of exceeding plume exposure pathway protective action guide levels at 10 miles”.

It must be remembered that like the plume phase EPZ, the ingestion phase EPZ is established to provide a planning basis. A

Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
×

specific incident might call for protective actions to be restricted to a small part of the ingestion phase EPZ or require that they be implemented beyond the ingestion phase EPZ as well.

Decision-making during the intermediate phase is not as difficult as that during the early phase. Environmental information is generally available because the release is terminated and plume deposition has occurred, allowing evaluation by emergency-response teams. Protective actions during the intermediate phase include not only protection against the ingestion of radioactive material but also protection against external exposure due to ionizing radiation from plume deposition. Protective actions are taken to ensure that (USEPA, 1992) (see Table 5.2):

  1. Dose in the first year does not exceed 20 mSv (2 rem);

  2. Dose in any single year after the first will not exceed 5 mSv (0.5 rem);

  3. The cumulative dose over 50 years (including the first and second years) will not exceed 50 mSv (5 rem).

Relocation of some people may take place during this phase to limit the general public’s long-term exposure to radiation as additional contaminated areas are identified. As areas are verified as not being contaminated, people who have been relocated may be allowed to return to them.

Exposure to radioactive iodine is possible through the ingestion pathway, so it is important that plans address this situation. Monitoring of the environment and food products controls this route of exposure. Removing contaminated products from the market and isolating contaminated products until the radioactive iodine decays to safe levels are the most effective way to eliminate radiation exposure and damage to the thyroid. That also eliminates the need for the use of KI by the general public as a protective action.

Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
×

Table 5.2 Protective Action Guides for Exposure to Deposited Radioactivity During the Intermediate Phase of a Nuclear Incident

Protective Action

Protective Action Guide (projected dose)a

Comments

Relocate the general populationb

>20 mSv (2 rem)

Beta dose to skin may be up to 50 times higher.

Apply simple dose reduction techniquesc

<20 mSv (2 rem)

These protective actions should be taken to reduce doses to low as practicable levels.

aThe projected sum of effective dose equivalent from external gamma radiation and committed effective dose equivalent from inhalation of resuspended materials, from exposure or intake during the first year. Projected dose refers to the dose that would be received in the absence of shielding from structures or the application of dose reduction techniques. See USEPA, 1992.

bPersons previously evacuated from areas outside the relocation zone defined by the Protective Action Guideline (PAG) may return to occupy their residences. Cases involving relocation of persons at high risk from such action (e.g., patients under intensive care) should be evacuated individually.

cSimple dose reduction techniques include scrubbing and/or flushing hard surfaces, soaking or plowing soil, minor removal of soil from spots where radioactive materials have been concentrated, and spending more time than usual indoors or in other low exposure rate areas (USEPA, 1992).

Late Phase Planning

The federal government does not provide specific guidance for protective actions during the late phase. Response to this phase depends on the specific incident. Planning requirements are general and address issues with re-entry and recovery methods used to determine relaxation of previous protective actions, periodic

Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
×

estimation of total population exposure, recovery organization, and communication.

KI Pharmaceutical Issues

KI Dosage forms

The current FDA-approved KI products for radioprotective use include

IOSAT®—130-mg tablet (Anbex).

THYROSAFE®—65-mg tablet (R. R. Registrations).

THYROBLOCK®—130-mg tablet (Wallace Labs; distributed by MedPointe, Inc.).

Source: Approved Drug Products with Therapeutic Equivalence Evaluations (“The Orange Book”) www.fda.gov/cder/ob/default.htm

FDA appropriately regulates KI for radioprotective use as an over-the-counter drug (that is, no prescription is required). Although the FDA Web site indicates that “only the KI products approved by FDA may be legally marketed in the United States”, other Web sites advertise numerous products for radioprotective use. Some advertise products as being FDA-approved and suggest in their general wording that the use of KI will be useful against NPP incidents and “dirty bombs” (for example, see NukePills.com). Only on closer examination of the site does the wording reveal that KI is to be used to protect the thyroid, not the rest of the body, in the event of radioactive iodine exposure.

The FDA Web site www.fda.gov/cder/drugprepare/kiprep.htm provides detailed information on home preparation for emergency administration of KI tablets to infants and small children. There are detailed instructions for the 65-mg and 130-mg tablets with dosing guidelines. Suggested “drink” vehicles include water, low-fat milk (white or chocolate), orange juice, such flat sodas as colas, raspberry syrup, and infant formula. Initially, the tablet is to be crushed and ground to a fine powder with a metal spoon. A volume of water is then added to solubilize the KI, and then an equal volume of the “drink” above. It is suggested that the resulting mixture should be

Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
×

refrigerated and can be stored for up to a week, after which it should be discarded. The instructions on the Web site clearly caution people numerous times regarding the differences between 65-mg and 130-mg tablets. The instructions are carefully detailed but may be impractical in an emergency situation. Therefore, there is a need for development of practical dosage forms (for example, 32-mg tablets or liquid formulations) for infants and children, the most vulnerable population; such a tablet size could also be convenient for adults.

At the time of the writing of this report, advertisements of KI products on various Internet sites sometimes implied that the products were FDA-tested and approved, had a 5-year shelf-life, and were available in various types of packaging. Radioprotective products described on such Web sites that are FDA-approved include

Iosat®.

ThyroSafe®.

ThyroBlock®.

Several other products are advertised as radioprotective, but they are not FDA approved at the time of writing this report.

A product not approved by FDA for use as a radioprotective should not be used for that purpose. Although some of the nonapproved products appear to be marketed as “dietary supplements”, this designation is not appropriate, inasmuch as the use of KI to prevent damage to the thyroid due to radioiodine exposure designates KI as a drug.

Additionally, although other legal products containing KI are available as nutritional sources of iodine, these typically contain only very small quantities and at the dosage used for nutritional replacement would not be expected to provide any significant thyroid protection.

Potassium iodate (KIO3) is available as a radioprotective for the thyroid in some European countries, but FDA does not approve it for use in the United States. KI is generally preferred to KIO3, which is believed to be a stronger gastrointestinal irritant.

Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
×

KI Shelf-Life

Distributed or stockpiled KI has a manufacturer-determined and FDA-acknowledged expiration date, so there is a need to replenish supplies periodically. Current FDA-approved formulations generally range in shelf-life from 2 to 3 years. It is well known that KI is extremely stable and should have a much longer shelf-life if stored under optimal conditions (for example, foil-wrapped for protection from air, moisture, heat, and light).

In March 2003, FDA (2003a) issued “draft guidance” for KI tablets shelf-life extension to provide guidance to state and local governments. It is a draft and is not officially available for implementation. There are two kinds of shelf-life extension: ordinary shelf-life extension with the manufacturer responsible for testing and DOD-sponsored shelf-life extension with FDA responsible for testing of stockpiled product.

Assay content and dissolution are the two specifications of concern in shelf-life consideration. None of the components of the KI tablets would be expected to significantly degrade or react with appropriate storage containers, but some KI tablets have failed to dissolute according to US Pharmacopeia (USP) specifications (75% within 15 min). However, the 75% dissolution was claimed to be achieved in a slightly longer period; this suggests that even if the USP requirement of 75% in 15 min were not reached, the product would be expected to be useful and provide appropriate protection. That is, the product should be considered as “usable”.

The March 2003 FDA draft document indicates that because KI is considered to be “very stable” when protected from moist air (KI is deliquescent and can release iodine and form iodate), additional testing “is probably unnecessary as long as the market package remains intact and continues to be stored under controlled conditions as described in the labeling.” A recommended protocol for shelf-life extension is also described with guidelines for accelerated stability testing with increased temperature and humidity) to achieve a 5-7-yr shelf-life designation. Recommendations for choosing a suitable laboratory for testing and the identification of batches qualified for extension and notification of expired batches are also discussed.

Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
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Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
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Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
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Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
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Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
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Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
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Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
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Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
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Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
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Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
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Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
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Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
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Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
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Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
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Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
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Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
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Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
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Suggested Citation:"5 Protective Measures." National Research Council. 2004. Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident. Washington, DC: The National Academies Press. doi: 10.17226/10868.
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Next: 6 Existing Distribution Plans for Potassium Iodide »
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Radioactive iodines are produced during the operation of nuclear power plants and during the detonation of nuclear weapons. In the event of a radiation incident, radioiodine is one of the contaminants that could be released into the environment. Exposure to radioiodine can lead to radiation injury to the thyroid, including thyroid cancer. Radiation to the thyroid from radioiodine can be limited by taking a nonradioactive iodine (stable iodine) such as potassium iodide. This book assesses strategies for the distribution and administration of potassium iodide (KI) in the event of a nuclear incident. The report says that potassium iodide pills should be available to everyone age 40 or younger—especially children and pregnant and lactating women—living near a nuclear power plant. States and municipalities should decide how to stockpile, distribute, and administer potassium iodide tablets, and federal agencies should keep a backup supply of tablets and be prepared to distribute them to affected areas.

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