ENCYCLOPEDIA OF Espionage, Intelligence, and Security Volume ...

Decontamination MethodsDuring the fall of 2001, L-Gel was successfully used todecontaminate offices of Congress and at ABC Newsfollowing the receipt of letters that were laced with anthraxspores.Strong bases, such as hydroxide forms of calcium,sodium hydroxide, and potassium are other useful chemicaldecontaminants. These agents disrupt chemical bondsin the contaminant and so destroy the offending compounds’noxiousness.Water is an ideal fluid for decontamination because avariety of chemically different detergents and soaps readilydissolve in water. These compounds can loosen or bindcontaminants and so remove them from a surface. Thefriction of scrubbing also aids in decontamination of theskin during hand washing.The different tendencies of chemicals to dissolvein water (a property known as solubility) affects the efficiencyof a decontaminant. For example, a longer periodof decontamination is needed when using a compoundthat is not readily soluble in water. This problem canbe somewhat overcome by the use of microemulsions,which are essentially very small droplets of thedecontaminant. The droplet coat is a material that is lesswater-soluble. The effect is best seen when oil is addedto water. Then, a sheen of oil appears on the water,rather than a homogeneous oil-water mixture. If a contaminantis not water soluble, it will quickly partition intothe hydrophobic (“water-hating”) decontaminant portionof a microemulsion. This can speed up the action of adecontaminant. Microemulsions can be applied to a contaminatedsurface as a spray, which can be washed off later.Thermal methods. Thermal decontamination is the use ofheat to vaporize those chemical contaminants that willreadily convert from a liquid to a gas in the presence ofheat. Both water- and alcohol-based chemicals can exhibitthis behavior.Water can also be heated, even to the extent of beingconverted to steam. Hot water or steam treatment can bean efficient means of decontamination of greasy or oilycontaminants. The use of moist heat, as in the laboratorysterilization unit called an autoclave, disrupts chemicalbonds in many microorganisms, killing them. Unfortunately,certain noxious bacteria that form spores (i.e.,Bacillus anthracis, Clostridium species) can, under somecircumstances, survive autoclaving.Hot air is another useful decontaminant for compoundsthat can be volatilized. This method is useful forsituations where a spill can be isolated and treated over alonger period of time. In a battlefield situation, other moreurgent methods are preferable.Nuclear DecontaminationNuclear decontamination in a battlefield site, to date onlyapplicable in the Japanese cities of Hiroshima and Nagasakiin the waning days of World War II, necessitates theremoval, burial, or storage of the contamination. However,in sites such as decommissioned nuclear powerplants or weapons manufacturing facilities, the less concentratedamounts of radioisotopes that are encounteredcan be more systematically decontaminated.Nuclear decontamination consists of the removal ofthe contaminating radioisotope. Removal can be accomplishedby the use of water-soluble chemicals (i.e., alkalinepermanganate, citric oxalic acid), fire-fighting foam,and even the electrochemical treatment of the contaminatedsurface.Personal DecontaminationThe specter of contamination with agents, in particularbiological agents, was seared into the public consciousnessin the latter months of 2001. Then, U.S. citizens weresubjected to terrorist attacks as letters containing Bacillusanthracis, the bacterium that is the cause of anthrax weremailed through the U.S. Postal Service.The concern over the use of biological weapons hasnot abated since that time. Indeed, the possibility of biologicalattack, and so the need for rapid decontamination,was one of the paramount concerns of U.S. troops andtheir allies involved in the war in Iraq in the winter andspring of 2003.Suspected exposure to an aerosol of a dangerousmicroorganism should be dealt with promptly. The exposedclothing should be taken off and safely contained soas not to contaminate bystanders or medical personnel. Itmay be necessary to destroy clothing depending on thesuspected contaminant. For example, spores of the anthraxbacteria can cling to clothing and retain their potentialfor infection for decades. Exposed skin should bedecontaminated. The best strategy is to use soap andwater with diligent scrubbing for at least 30 seconds. Theuse of diluted household bleach is acceptable.Decontamination in the case of biological exposure istypically done in an isolated facility, where the access ofpersonnel is tightly controlled, and the outgoing air can befiltered to prevent the spread of the biological agent. Suchfacilities are even used in the battlefield setting.In battlefield settings such as Iraq, the military can usea dried resin known as M291. This resin is a dry blackcarbon containing material that decontaminates by absorptionand physical removal of the chemical agentsfrom the victim. M291 resin is particularly useful for localized(“spot”) decontamination of exposed skin.Organization of a military treatment area. Part of militarystrategy in conflicts where there is a potential for the use ofbiological or chemical weapons, as in the Iraq conflict of2003, is the establishment of medical treatment facilities.In the battlefield a facility is divided into two zones. Onezone (the “dirty” zone) is where contaminated personneland equipment are segregated. The other, “clean” zone is318 Encyclopedia of Espionage, Intelligence, and Security