Saturday, October 07, 2006

Prepared For Terror Attacks? - Radiological

Here is the next excerpt from the excellent Rand Corporation book, "Individual Preparedness and Response to Chemical, Radiological, Nuclear, and Biological Terrorist Attacks." See my previous post for more on this and for the excerpt on chemical attack preparedness.

To see the entire monograph in pdf form, go to: http://www.rand.org/pubs/monograph_reports/MR1731/index.html

Excerpt - Radiological Attack

"A dirty bomb uses conventional explosives to disperse radioactive material across a wide area, although slower and less dramatic methods are possible and may escape detection. The area affected by a radiological attack could be fairly small—a few blocks—or could cover hundreds of square kilometers with low-level radiation, depending primarily on the type and amount of radioactive material used. The hazards to individuals from the radiation are likely to be quite low and will manifest themselves only after many years, if they do so at all. For those close to the explosion, the hazards from the blast are much higher. While indoor attacks are also possible, outdoor attacks have the potential to affect more people, cause more social anxiety, and contaminate a larger area than indoor attacks.

"The hazard from a radiological bomb results from two categories of exposure. The primary short-term exposure hazard is inhalation of radioactive material suspended with the dust and smoke from the explosion. Inhaled radioactive material can be deposited in the lungs and will continue to expose the individual to radiation for as long as the material remains in the lungs, which can be many years. A second, long-term external exposure hazard exists for individuals who remain in the contaminated areas over a period of years. Although there is considerable debate in the scientific community about the effects of low levels of radiation on individuals (e.g., Jones, 2000), it is likely that authorities will take steps to address this risk, either by limiting access or decontaminating the area (Levi and Kelly, 2002)."
...
"Support from Officials/Governments. Since detectors are required to signal the presence of radiological materials, the government will likely play a central role in the response to any such attack. However, because it could take an hour or more to detect the radiation, individuals within the cloud will not know that radiation is present immediately following the event, the period when the risk from inhalation is greatest.

"Individual’s Primary Needs. Fundamentally, an individual needs to avoid exposure to radiation, particularly through inhaling radioactive dust from the cloud. If exposed, an individual should also seek medical care as soon as it is safe."
...

Recommended Actions

"1. If an explosion occurs outdoors or you are informed of an outside release of radiation and you are outside, cover nose and mouth and seek indoor shelter. If you are inside an undamaged building, stay there. Close windows and doors and shut down ventilation systems. Exit shelter when told it is safe.

"2. If an explosion occurs inside your building or you are informed of a release of radiation, cover nose and mouth and go outside immediately. The primary safety and health hazard in a radiological attack is inhalation of radioactive particulate matter generated from an explosion or other type of release (e.g., aerosol). A simple and effective way to prevent this is to take shelter in a structure that blocks the infiltration of particulates. This action is attractive because it is simple, quick, and effective. The onset of the exposure hazard in a radiological attack initiated with a bomb is expected to be immediate, and the exposure is greatest in the first few hours, while the particulate matter is still airborne. For individuals outside when such an attack occurs, sheltering in a nearby building will provide good protection and should be attempted immediately. The closest shelter not damaged or endangered by the explosion should be sought because the goal is to minimize exposure to suspended particulate matter.

Individuals already indoors should remain there as long as their building has not been damaged and is not threatened by fires or other consequences of the attack.

"The primary complication with this action is that it is unlikely to be apparent that any radioactive material has been released for some time. However, this action is generally advisable in response to any explosion event because many types of nonradioactive dust present health hazards and should be avoided as well. In addition, sheltering will help counter the tendency for people to gather at an explosion site, thus decreasing the impact of any secondary device that may target those who gather at the scene. As a result, finding shelter should be the goal in any explosion. Once emergency responders begin to understand the type and extent of radioactive contamination, they can provide guidance about when and how to vacate shelters. Respiratory protection should be used to prevent inhalation of radioactive particulate matter. As with sheltering, a complication of this action is that the release of radioactive material is unlikely to be apparent for some time. However, for the same reasons as with sheltering, this action is beneficial in the response to any explosion event, whether radioactive material is present or not. There are two primary variations of respiratory protection: expedient and particulate filter equipped facemasks. Expedient respiratory protection refers to using available materials, such as clothing or towels, as filter material.


"For individuals outside when such an attack occurs, expedient respiratory protection will be necessary, because the onset of the hazard is expected to be so rapid that effective use of a filter mask will be either impractical (i.e., it will have to be carried at all times) or too slow (because an individual would need to travel to a car or other storage space to retrieve it). Evaluation of expedient respiratory protection shows that a wide variety of common materials have similar filtration efficiencies, with the efficiency increasing with the number of layers used (Guyton et al., 1959; Sorensen and Vogt, 2001b). According to those sources, wetting the material makes it no more effective and also increases breathing resistance and so should not be done. Given that most likely expedient filtration materials have similar protective capacities, the primary concern is obtaining a good seal around the nose and mouth. Thus, while understanding that options may be very limited, one should strive to use soft cloth and fold, cut, or tear it so that it can be handled in such a way as to hold it tightly over the nose and mouth. If tape is available, the material should be taped to the face to improve the seal. A substantial shortcoming of expedient respiratory protection is that it requires at least one hand to hold it in place, thereby decreasing agility and mobility. In addition to improving the seal, taping the mask to the face can eliminate this problem. In any case, one should keep in mind that the respiratory hazard increases with the cumulative inhalation exposure, so even if expedient respiratory protection must be temporarily removed, it should be replaced as soon as possible. Individuals indoors should evacuate the premises if the attack occurs indoors or damages or threatens their building enough to undermine its sheltering capacity.

"In this situation, a particulate filter mask may be appropriate. Regular building occupants could store a filter mask in their work space for rapid retrieval and donning in the event of a radiological attack or other explosion. These masks are much more effective than expedient measures, are inexpensive, are widely available, are compact, have long shelf lives, have minimal maintenance requirements, and are simple to use. We therefore recommend their use for anyone indoors in a potential indoor radiological attack.

"3. Decontaminate by removing clothing and showering. Radioactive particulate matter trapped on a person’s clothing, hair, or skin can pose an exposure hazard that remains even after direct contact from suspended particulate matter has been eliminated. Therefore, anyone who has been exposed to radioactive material should undergo decontamination once safely sheltered from the source of radioactive material. Decontamination should initially focus on removing any respirable dust, which would entail removing outer clothing and securing it in a bag or other container. While the hazard is primarily respiratory, contact of radioactive material with skin and eyes should be minimized by rinsing exposed skin, removing contact lenses, and showering as soon as possible. The danger posed by contaminated clothing may persist for long durations, so contaminated clothing should be treated or disposed of in accordance with official guidance.

"4. Relocate outside the contaminated zone, only if instructed to do so by public officials.
Although contamination levels from a radiological weapon are likely to be quite low, long-term exposure may be high enough in some areas that authorities will ask individuals to leave their homes or businesses for some period of time. Relocation does not need to be done quickly because it is the exposure over many years that is the concern; the relocation could happen over weeks or months. Individuals may be allowed to return within a few months if the area is to be decontaminated, but it may also be many years before individuals will be allowed to return. Individuals will have to rely on authorities for information about whether relocation is called for and how long it is likely to last."


More Excerpts to Come

I will be posting more excerpts regarding nuclear and biological terrorist attacks soon.

Get Ready, Seriously ... www.safecastle.net

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