chapter 16 - decontamination of chemical causal ties - pg. 527 - 558

8/3/2019 Chapter 16 - Decontamination of Chemical Causal Ties - Pg. 527 - 558

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Decontamination of Chemical Casualties

Chapter 16

DECONTAMINATION OF CHEMICALCASUALTIES

ERNEST H. BRAUE, JR, PHD*; CHARLES H. BOARDMAN, MS, ORR/L; ANDCHARLES G. HURST, MD

INTRODUCTION

MILITARY AND CIVILIAN DECONTAMINATION PROCEDURES

ACTION OF CHEMICAL AGENTS ON THE SKIN

BARRIER SKIN CREAMS

METHODS OF DECONTAMINATION

WOUND DECONTAMINATION

PATIENT THOROUGH DECONTAMINATION

EQUIPMENT FOR PATIENT THOROUGH DECONTAMINATION

ESTABLISHING A PATIENT THOROUGH DECONTAMINATION AREA

DECONTAMINATION IN COLD WEATHER

SPECIAL POPULATIONS

SUMMARY

*Scientist, US Army Medical Research Institute of Chemical Defense, 3100 Ricketts Point Road, Aberdeen Proving Ground, Maryland 21010-5425Lieutenant Colonel, US Air Force; Instructor, Air Force Liaison, and Occupational Therapist, US Army Medical Research Institute of Chemical

Defense, 3100 Ricketts Point Road, Aberdeen Proving Ground, Maryland 21010-5425Colonel (Retired), Medical Corps, US Army; Director, Chemical Casualty Care Division, US Army Medical Research Institute of Chemical Defense,

3100 Ricketts Point Road, Aberdeen Proving Ground, Maryland 21010-5425


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Medical Aspects of Chemical Warfare

INTRODUCTION

Decontamination is the process of removing orneutralizing hazardous substances from people, equip-ment, structures, and the environment.1,2This chapterfocuses on the safe decontamination of medical casual-

ties exposed to chemical agents; however, the patientdecontamination process discussed here also is appro-priate for those exposed to biological and radiologicalhazards (although procedures, operator protectiveensemble, and detectors may vary slightly).

Decontamination performed within the first fewminutes after exposure is the most effective for protect-ing the patient, although later skin decontamination,which can benefit the patient by reducing the agentdose, should not be ignored. Early skin decontamina-tion can often mean the difference between patientsurvival (or minimal injury) and death (or severeinjury). Patient decontamination serves two primary

purposes: (1) protecting the casualty by removingharmful agents from the skin, thus reducing the doseand severity of the agents hazardous effects, and (2)

protecting emergency responders, transport personnel,medical personnel, and other patients from second-ary exposure. Cross contamination from dry or liquidagent on the patients clothing or skin can sicken others

or make equipment temporarily unusable. Cloth fiberscan hold agent liquid and vapors. The off-gassing ofliquid contaminants, or vapor trapped in clothing andhair, can cause those who work near the casualty to be-come symptomatic if they are not wearing respiratoryprotection. Often removing clothing and brushing thehair greatly reduces the level of contaminant carriedon the patient; in some instances, these actions are theonly necessary decontamination.

Contaminated persons who present for decontami-nation may additionally have conventional wounds,psychological stress reactions, physiological reactionsto heat or cold, or any combination of these. Persons

wearing individual protective ensemble (IPE) areparticularly prone to heat injuries caused by extendedtime in this gear.

MILITARY AND CIVILIAN DECONTAMINATION PROCEDURES

The decontamination of chemical casualties is achallenging task that may require large numbers ofpersonnel, water and equipment resources, and time.Casualty decontamination takes place at all levels ofpatient care, from the exposure site to the door of themedical treatment facility (MTF). In the military, thereare three levels of patient decontamination (these sameprocesses may differ in the civilian sector)3:

1. Immediate decontaminationis conducted by theindividual exposed to the agent, or anotherindividual (a buddy), who comes to assistthe victim, as soon as possible after exposure.Ideally it is performed within minutes afterexposure. The individual decontaminatesexposed skin and garments using a militarydecontamination kit. If a kit is not available,any material, dry or wet, that can be appliedor used to physically remove agent from the

skin is beneficial. This process is very effec-tive in reducing the hazard posed by agent onthe skin, particularly if IPE is already beingworn.

2. Patient operational decontamination is carriedout by members of the individuals unit toprepare the individual for transport. At thislevel the casualty is kept in IPE, from whichany large concentration of agent is removed.The casualty is placed on a litter covered

with plastic and loaded into a transport ve-hicle dedicated to evacuating contaminatedpatients. Evacuation vehicles are kept wellventilated, and crew members wear protec-tive ensemble. Operational decontaminationhelps to reduce the level of contaminationon the patient, thereby reducing the level ofcross contamination to the transport vehicle.This level of decontamination allows forlarge numbers of contaminated casualties tobe quickly evacuated to patient decontami-nation facilities that are prepared to handlethem.

3. Patient thorough decontaminationis performedoutside the MTF that receives the contaminat-ed patients. At the decontamination stationthe patients clothing is removed and theirskin and hair are thoroughly decontaminated.It is critical that patients are prevented from

entering a medical facility until patient thor-ough decontamination has been conducted.

In civilian industry, workers are usually trained inself-decontamination methods pertinent to the haz-ards for that setting. In a civilian or homeland defensescenario, however, immediate decontamination bythe victims themselves may not be possible becausethey may not have access to decontaminants or knowwhat to do. Immediate decontamination in a civilian


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setting is often referred to as emergency decontamina-tion, self decontamination, or buddy rescue. The firstdecontamination in the civilian setting may not occuruntil a fire department decontamination unit arrives.Patient operational decontamination might not readilyapply in the civilian setting because private ambulance

services may refuse to accept contaminated patientsand civilian patients do not have IPE.Individuals who escape the scene of the release

before the arrival of the first responders may manageto access transportation while still in contaminatedclothing. This was the case during the Tokyo subwaysarin attack, in which many victims either walkedor took taxis to hospitals.4Otherwise, contaminatedindividuals must be moved to a decontaminationstation established by the fire department or set up ata hospital for patient thorough decontamination. De-

contamination stations near the incident site are oftenreferred to as mass casualty decontamination stationsor gross decontamination areas.2,5Victims might alsobe moved to a water source, such as a hose or shower,for buddy decontamination. Because fleeing casualtiesmight bypass decontamination, or responding fire

departments may fail to perform adequate decon-tamination, it is important that every hospital has thecapability of establishing its own patient thoroughdecontamination area outside its entrance.

Since the events of September 11, 2001, military andcivilian agencies have sought to improve their patientdecontamination capabilities.6Industry has respondedwith a wide array of decontamination equipment andmaterials for simplifying this process. Civilian andmilitary sectors are now much better prepared for thechallenges of patient decontamination.

ACTION OF CHEMICAL AGENTS ON THE SKIN

Crone described the function of the skin as a barrierand the possible effect of chemical agents on tissues:7,8

The skin consists of a number of layers of living cellsof varied function bounded on the outside by a thinlayer of dead cells, the stratum corneum. This layeris the main diffusion barrier to the entry of foreignsubstances. The blood supply to the skin does notreach directly to the epidermis. Therefore, a liquidcontacting the skin surface first has to penetrate thestratum corneum, and then diffuse through the largelyaqueous medium of the cell layers to the nearest bloodcapillaries, from whence it is carried round the body.

There is opportunity for a chemical to be bound tothe outer skin layers, so that further delay and stor-age can occur.7

Chemicals that act directly on the skin, such assulfur mustard, need little penetration for their ef-fects to begin; they act directly on the integrity of theskin cells. This same process occurs with other highlyreactive chemicals such as acids and alkalis. Moresystemically acting chemicals, such as nerve agents,may need to cross the skin barrier before they can affectbody systems. Generalizations about the permeabilityof skin are often inadequate.8The skin is not a simplesystem, and its permeability depends on many fac-tors including temperature and the skins thickness,integrity, and hydration.

The stratum corneum retains moisture and providesa barrier to outside hazards. This barrier is very effec-tive against water-soluble chemicals. However, it ismore permeable to fat-soluble (lipophilic) chemicalsbecause of the layers of lipids in the epidermis thatunderlie and surround the keratinized dead skin

cells making up the stratum corneum.8 When trac-ing agent progress from the surface of the skin to thebloodstream, three skin compartments must beconsidered: (1) the outer application layer, where theagent lies on the skin; (2) the boundary layer, wherethe agent is moving through the skin; and (3) the areawhere a dermal reservoir of agent that has diffusedinto the lipid area of the stratum corneum may form.9Rapid decontamination seeks to prevent large dosesof agent from penetrating to the lipid area of the stra-tum corneum and subsequently into the circulation.Later decontamination seeks to remove any agent that

remains on the surface of the skin.A liquid chemical warfare agent (CWA) is often

thought to be accessible on the surface of the skin for upto 3 minutes, taking approximately 30 minutes for theagent to cross the skin barrier and enter the capillaries.Some of the hazardous agent is likely to be temporarilysequestered in the skin during this transit. Accordingto Buckley et al,10inappropriate skin treatments couldtheoretically aid in the dermal transit of agent, and theresulting store of hazardous agent could potentiallymake the situation worse for the victim.10

Most CWAs (particularly VX and mustard) aremoderately fat-soluble, enabling them to be absorbedthrough the stratum corneum over time. Lipid-solublechemical agents move quickly throughthe lipids sur-rounding the cells in the stratum corneum and thenmore slowly into the hydrophilic (water-soluble)bloodstream.

Contact time, concentration, solubility, temperature,hydration state, and physical condition of the skin areall factors that affect the absorption of agent throughthe skins epithelial layer. Vascularity of tissue plays an


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important part in the rate at which agents access thebloodstream and act systemically on the body. Studiesby Lundy et al11administering VX dermally to juvenilemale Yorkshire-Landrace cross pigs and earlier experi-ments on dermal VX exposure on human subjects bySim12 showed that skin that was highly vascularized

EXHIBIT 16-1

VX STUDIES

Lundy et al1conducted a study in which 31 Yorkshire-Landrace cross pigs were exposed to pure liquid VX,and VX in isopropyl alcohol. Both of these exposureswere at the calculated median lethal dose. In someanimals the nerve agent was placed on the ventralsurface of the ear (thin tissue with generous bloodflow), and on others the agent was placed on the

belly just above the naval (thicker tissue with a lesspervasive blood flow). Liquid agent absorption wasmeasured by blood cholinesterase inhibition. Thoseswine with VX applied to the ear showed morethan 90% cholinesterase inhibition within 45 min-utes, resulting in apnea (within 2 hours) requiringventilatory assistance thereafter and death within45 minutes after ventilatory support was initiated.Those animals with belly VX exposure showed only75% cholinesterase inhibition within the 6-hourtimeframe of the experiment, but developed thesame progression of symptoms requiring venti-latory support. In neither case were the animalsprovided with antidotes within the time periodthat would have slowed or ameliorated the effects.This study demonstrates, in part, that death fromliquid VX can be delayed by up to several hoursdepending on a variety of factors, one being thespecific body area exposed. Earlier human studies

by Sim2also show the variable and delayed effectsof exposure to liquid VX.

Data sources: (1) Lundy PM, Hamilton MG, Hill I, Conley J,Sawyer TW, Caneva DC. Clinical aspects of percutaneous poi-soning by the chemical warfare agent VX: effects of applica-tion site and decontamination.Mil Med.2004;169:856-862. (2)Sim VM. VXPercutaneous Studies in Man. Aberdeen ProvingGround, Md: US Army Chemical Research and DevelopmentLaboratories; 1960.Technical Report 301.

led to more rapid systemic agent effects as indicated byreduced levels of acetylcholinesterase. Sims studyalsonoted that VX spread thinly over areas of the skin hadmuch less of an effect on acetylcholinesterase, a reducedsystemic effect, than the agent concentrated in one area,which increased the penetration rate (see Exhibit 16-1).

BARRIER SKIN CREAMS

History

Improving the skin as a barrier to chemical agentshas been a concern since at least World War I, whensulfur mustard (HD) was first used in warfare. Ap-

plying a topical protectant to vulnerable skin surfacesbefore entry into a chemical combat arena was pro-posed as a protective measure against percutaneousCWA toxicity soon after Germany used HD at Ypres,Belgium, in 1917.13 The US Army began examiningvarious soaps and ointments for protective capabilitiesin the summer of that year. Although several simpleformulations were found to be effective in reducingskin redness produced by agents such as hydrogensulfide, no product was available before the end of

the war.13

Research continued but did not producea fielded product before World War II began. Dur-ing World War II, a concentrated effort to developointments for protection against HD took place atthe Chemical Warfare Service, Edgewood Arsenal,Maryland. The Army produced the M-5 protectiveointment, which was manufactured in 1943 and 1944.However, because of limited effectiveness, odor, andother cosmetic characteristics, the M-5 ointment wasno longer issued to soldiers by the mid 1950s.14

Skin Exposure Reduction Paste Against ChemicalWarfare Agents

Between 1950 and the early 1980s, research focusshifted to medical countermeasures rather than pro-tective creams. Then, a limited research effort at thesuccessor to the Chemical Warfare Service, the USArmy Medical Research Institute of Chemical Defense(USAMRICD), produced two non-active barrier skincream formulations based on a blend of perfluorinatedpolymers. The two formulations were transferred toadvanced development in October 1990.15The bestformulation was selected and progressed throughdevelopment as an investigational new drug filedwith the US Food and Drug Administration in 1994and approval of a new drug application in 2000. Thisnew product was called skin exposure reductionpaste against chemical warfare agents (SERPACWA).SERPACWA consisted of fine particles of polytetra-fluoroethylene solid (Teflon; DuPont, Wilmington, Del)dispersed in a fluorinated polyether oil. The excellentbarrier properties of this polymer blend were related tothe low solubility of most materials in it. Only highlyfluorinated solvents like Freon (DuPont, Wilmington,


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Del) were observed to show appreciable solubility.SERPACWA is now a standard issue item to US forcesfacing a threat of CWA use.

Function

SERPACWA is an antipenetrant barrier cream foruse by service members to protect against the toxic ef-fects of CWAs (eg, blister [vesicant] and nerve agents)and percutaneously active biological agents. Whenused in conjunction with IPE, or mission-orientedprotective posture (MOPP) gear, SERPACWA willprevent or significantly reduce the toxicity followingpercutaneous exposure to such agents. It is used as anadjunct to IPE, not as a substitute. The effective barrierof SERPACWA also has been found to protect againstpoison ivy and poison oak.

Effectiveness

SERPACWA was developed to extend the protectionafforded by the current protective garments and allowsa longer window for decontamination. It provides forexcellent protection against liquid challenges of GD(soman), VX, and HD, but its protection against HDand GD vapor is less than optimal. It does not neutral-ize CWAs into less toxic products.

Application

SERPACWA is used at the direction of the com-mander. Each service member is issued six packets of

SERPACWA, sufficient material for six applications orfor 2 days of use. Its effectiveness depends on the thick-ness and integrity of the layer applied and the lengthof time between application and agent exposure (weartime). The cream should be applied first to skin areasadjacent to IPE closures (such as at the neck, wrists, andlower legs around the top of the boots). If the situationpermits, SERPACWA should also be applied to thearmpits, groin area, creases and crack of the buttocks,and around the waist. It is not applied to open wounds.It should never be applied to the entire body, becauseits occlusiveness can interfere with the ability to dis-sipate heat. Under normal conditions, SERPACWA iseffective when spread over the skin as a thin layer (0.1mm thick, or 0.01 mL/cm2). One packet of SERPACWAcontains 1.35 fluid ounces (about 2.7 weight ounces or84 g) for one application. This amount of SERPACWAis sufficient to cover the indicated skin areas with asmooth coating that has a barely visible cream colorand is slightly detectable by touch.

SERPACWA is not water soluble, so it cannot bewashed off by water or removed by sweat without

brushing and scrubbing, but it may physically wearoff with time. Abrasion of SERPACWA by clothing orother contacts, such as sand or dirt, will reduce thewear time. SERPACWA must be reapplied if the coat-ing becomes embedded with particulate matter (dirtor sand), if the sites are decontaminated, or after 8

hours on the skin. Normally, SERPACWA is effectivefor 4 hours in preventing CWAs from contacting andpenetrating the skin. Insect repellents such as DEET(N,N-diethyl-meta-toluamide) decrease its effective-ness. If DEET is wiped off before application using adry towel, gauze, or piece of cloth, SERPACWA canstill provide significant protection.

Effects on Decontamination

The use of SERAPCWA makes decontaminationeasier in areas protected by the barrier. It is easier tophysically remove CWA from a SERPACWA layer than

from the skin. Service members should still performskin decontamination immediately after chemicalcontamination, because SERPACWAs effectivenessdecreases with time. SERPACWA can be removedby brushing and scrubbing the skin areas with soapand water. SERPACWA has no vapors, so it does notregister a false alarm with automatic vapor detectorssuch as the improved chemical agent monitor (ICAM),nor does it register with systems that detect chemicalliquid such as M8 paper. M8 paper, however, detectsagent on the surface of the SERPACWA layer (however,it has been noted that if moist SERPACWA paste coatsthe surface of M8 paper, it can prevent CWA from

contacting the paper).

Active Barrier Creams

In 1994, to overcome the limitations of SERPACWA,USAMRICD began development of an improved sub-stance that would act as both a protective barrier andan active destructive matrix to detoxify CWAs. Thetypes of molecules that could potentially neutralize ordetoxify CWAs have been known for a long time. Thesecompounds fall into three general classes: oxidizers,reducers, and nucleophiles. The USAMRICD research-ers were required to find a final formulation that doesnot irritate the skin, however, which eliminated manyof the most reactive species. The aprotic nonpolarenvironment of SERPACWA provides a unique butchallenging medium for active moieties to neutral-ize CWA. Reaction mechanisms that do not involvecharged transition states are favored in this medium.The improved SERPACWA containing a reactive ma-trix became known as active topical skin protectant(aTSP). Four criteria were established for aTSP: (1) the


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protectant must neutralize CWAs including HD, GD,and VX; (2) the barrier properties of SERPACWA mustbe maintained or increased; (3) protection against HDand GD vapor must be increased; and (4) the cosmeticcharacteristics (eg, odor, texture) of SERPACWA mustbe maintained.16Additionally, aTSP could not degrade

a soldiers performance.Using the two components of SERPACWA, per-fluorinated polyether oil and polytetrafluoroethyl-ene solid, as a base cream, USAMRICD scientistsevaluated over 150 different active components.Classes of compounds tested included organic poly-mers, enzymes, hybrid organic-inorganic materials,polyoxometalates, inorganic composites, inorganic

oxides, metal alloys, and small organic molecules.These compounds were incorporated into the basecream to produce over 500 candidate formulations(see Table 16-1).17

Two candidate formulations were selected fortransition to advanced development. The lead aTSP

formulation, a mixture of organic polymers, surfac-tants, and the base cream of perfluorinated-polyetheroil and polytetrafluoroethylene solid, was ready foradvanced development in 2004. Although it is not cur-rently funded for further research, this new productis expected to dramatically improve protection fromCWAs when it is fielded, and it may reduce the needfor a full protective ensemble.

TABLE 16-1

PATENTS COVERING WORK ON ACTIVE TOPICAL SKIN PROTECTANT AT THE US ARMY MEDI-CAL RESEARCH INSTITUTE OF CHEMICAL DEFENSE

Name Authors US Patent No. Date

Active Topical Skin Protectants ContainingOPAA Enzymes and CLECs

Braue EH Jr et al (Hobson, Govardhan,and Khalaf)

6,410,603 6/25/2002

Active Topical Skin Protectants ContainingS-330

Braue EH Jr et al (Mershon, Braue CR, andWay)

6,472,438 10/29/2002

Active Topical Skin Protectants Using Poly-oxometalates

Braue EH Jr et al (Hobson, White, andBley)

6,420,434 7/16/2002

Active Topical Skin Protectants UsingPolyoxometalates and/or Coinage MetalComplexes

Braue EH Jr et al (Hobson, Hill, Boring,and Rhule)

6,414,039 7/2/2002

Active Topical Skin Protectants Braue EH Jr, Hobson ST, Lehnert EK 6,472,437 10/27/2002

Active Topical Skin Protectants Using Poly-mer Coated Metal Alloys

Hobson ST, Braue EH. Jr, Back D 6,437,005 8/20/2002

Active Topical Skin Protectants Using Reac-

tive Nanoparticles

Hobson ST et al (Braue, Lehnert,

Klabunde, Koper, and Decker)

6,403,653 6/11/2002

Active Topical Skin Protectants UsingOrganic Inorganic PolysilsesquioxaneMaterials

Hobson ST, Braue EH Jr, Shea K 6,417,236 7/9/2002

Active Topical Skin Protectants Using Com-binations of Reactive Nanoparticles andPolyoxometalates or Metal Salts

Hobson ST et al (Braue, Lehnert,Klabunde, Decker, Hill, Rhule, Boring,and Koper)

6,410,603 6/25/2002

Polyoxometalate Materials, Metal-Contain-ing Materials, and Methods of Use Thereof

Hill CL et al (Xu, Rhule, Boring, Hobson,and Braue)

6,723,349 4/20/2004

METHODS OF DECONTAMINATION

The first and most effective method of decontamina-tion is timely physical removal of the chemical agent.

To remove the substance by the best means availableis the primary objective of effective decontamination.Chemical destruction (detoxification) of the offending

agent is a desirable secondary objective (but is not al-ways possible). Physical removal is imperative because

none of the chemical means of destroying these agentswork instantaneously.

The US military has actively explored personnel and


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patient decontamination methods since World War I,the beginning of modern chemical warfare (Figure16-1). Many substances have been evaluated for theirusefulness in skin decontamination. The most commonproblems with potential decontaminants are irritationof the skin, toxicity, ineffectiveness, or high cost. Anideal decontaminant would rapidly and completelyremove or detoxify all known chemical (as well asbiological and radiological) warfare agents from bothskin and equipment (Exhibit 16-2). Decontaminants

used for equipment have often been considered forhuman skin but are found unsuitable because theycause chemical burns.18

Recent research has explored the use of water, soapand water, polyethylene glycol and polyvinylpyrroli-done19; polyethylene glycol (PEG 300, PEG 400) andglycerol or industrial methylated spirit mixtures20;hydrogen peroxide foam mixtures (Sandia foam, Mo-dec Decon Formula)21; immobilized enzymes (Gordonsponge)2225; cyclodextrines26; ozones (L-Gel)27; organo-phosphorus acid anhydrolases28; phosphotriesterases29;chloroperoxidases30;a mixture of bovine hemoglobin,gelatin, and poi31; blends of catitonic and anionic

tensides32

; hydroperoxides and hydroperoxycarbon-ate anions, dichloroisocyanurate, and oxidants suchas sodium hypochlorite and calcium hypochlorite33;polyglycol and corn oil34; and technology such as theuse of atmospheric pressure plasma jets35and postex-posure cooling.36

Currently recommended decontamination materialsfor US service members that are safe for human skin in-clude soap and water (hydrolysis is probably the most

Fig. 16-1.(a)Treatment barracks for gas cases. Evacuation Hospital #2 [ca World War I]. (b)Mobile degassing unit #1. Tours,France. November 21, 1918.Photographs: Courtesy of the National Museum of Health & Medicine, Armed Forces Institute of Pathology (a: Reeve 1179;

b: Reeve 12196).

a b

economical choice if water is readily available in amplequantities); dry decontaminants (eg, fullers earth,M291 skin decontamination kit [SDK]); packaged liq-uid decontaminants (eg, the Canadian-manufacturedReactive Skin Decontamination Lotion [RSDL; E-Z-EMCanada Inc, Anjou, Quebec, Canada]); and chemicaldecontaminants that create an oxidative reaction withthe agent (eg, dilute 0.5% hypochlorite solution [dilutebleach]). Table 16-2 gives the suggested applicationsfor the various decontamination materials.

HD and the persistent nerve agent VX contain sul-fur atoms that are readily subject to oxidation and/or dehydrochlorination reactions. VX and the othernerve agents (GD, GA [tabun], GB [sarin], and GF[cyclosarin]) contain phosphorus groups that undergoalkaline hydrolysis. HD can also be neutralized byhydrolysis or other nucleophilic substitution, but therate is generally slow. Therefore, most chemical decon-taminants are designed to neutralize CWAs by eitheroxidative chlorination or hydrolysis.1

Soap and Water: Hydrolysis

Many classes of CWA, including HD, V agents, andG agents, can be detoxified by reaction with nucleo-philes (water is the nucleophile). Chemical hydrolysisreactions are either acid or alkaline. Acid hydrolysisis of negligible importance for agent decontaminationbecause the hydrolysis rate of most chemical agents isslow, and adequate acid catalysis is rarely observed.8

Alkaline hydrolysis is initiated by the nucleophilicattack of the hydroxide ion on the phosphorus atoms


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found in VX and the G agents. The hydrolysis rateis dependent on the chemical structure and reac-tion conditions such as pH, temperature, the kind ofsolvent used, and the presence of catalytic reagents.The rate increases sharply at pH values higher than8, and increases by a factor of 4 for every 10C rise intemperature.37Many nucleophilic agents are effectivein detoxifying chemical warfare agents; unfortunately,many of these (eg, sodium hydroxide) are unaccept-ably damaging to the skin. Alkaline pH hypochloritehydrolyzes VX and the G agents quite well.1,38,39

The rate of detoxification of HD in water, however,is slow and depends more on the limited solubility ofHD in water (approximately 0.8 g/L at room tempera-ture) than on the reaction rate of hydrolysis (half-life

at 20C is 14.7 min). HD is highly soluble in oils andfats.40The hydrolysis rate is not affected by pH anddecreases with increasing salt concentration in aqueoussolutions (seawater and saline intravenous bag). Us-ing stronger nucleophiles such as sulfides and aminesdoes not increase the reaction rate, because the rate-

determining step is the initial formation of the cyclicethylene sulfonium ion, which forms directly from theHD molecule. Thus, while nucleophilic detoxificationof HD is possible, oxidative chlorination is much moreeffective, although still slow.8

Liquids are best for decontaminating large or ir-regular surface areas. Soapy water solutions are wellsuited for MTFs with adequate water supplies. Soapand water are low-cost materials that remove agentsby hydrolysis and by simply washing them away ifused in copious amounts. These solutions do not killbiological agents or neutralize radiological or chemicalagents; therefore, water run-off must be collected. Liq-

uid soap acts as a surfactant. The surfactant moleculereduces the water surface tension, making it wetterso that it spreads out. Also, one end of the surfactantmolecule is soluble in oily substances, and the otherend is soluble in water.41,42This enables water to betterloosen and suspend agent particles in the water so theycan be washed away.Fat-based soaps and emulsifiers/surfactants (eg, Dawn dishwashing liquid [Procter &Gamble, Cincinnati, Ohio],43baby shampoo, castileliquid soap, or soft soap) are much more effective thandetergents that dry the skin (the latter should not beused).44Soap and water is best used during patientthorough decontamination, but also can be used for

immediate and operational patient decontaminationif available and practical. Copious amounts of soapand water should not be used on the joint service light-weight integrated suit technology or similar MOPPgarments, because dampening the fabric reduces itsprotective abilities.

Dry Decontaminants

Any material that can absorb a liquid and thenbe brushed or scraped off without abrading the skincan be used as an effective skin or equipment decon-taminant to remove liquid agents. Clean sand, bakingpowder, fullers earth, diatomaceous earth, and babywipes (dry or wet) can be applied to the agent, allowedto absorb it, and then carefully wiped away. Initially,large quantities of thickened liquid agent can be re-moved from clothing and skin by scraping it off withan uncontaminated stick or similar device.

Van Hooidonk45 conducted animal studies todetermine the effectiveness of common householdcompounds for decontamination of liquid agents on

EXHIBIT 16-2

DESIRABLE TRAITS OF A SKINDECONTAMINANT

Effective against chemical, biological, radiologi-cal, and nuclear agents, toxic industrial mate-rial, toxic industrial chemicals, and new threatagents.

Neutralizes all chemical and biological

agents.

Safe (nontoxic and noncorrosive) for skin,eyes, and wounds.

Removes agent from below the skin sur-face.

Applied easily by hand. Readily available.

Acts rapidly over a wide temperaturerange.

Produces no toxic end products.

Stable in long-term storage.

Stable in the short term (after issue to unit /individual).

Affordable.

Does not enhance percutaneous agent ab-sorption.

Nonirritating.

Hypoallergenic.

Disposed of easily.

Data sources: (1) Chang M. A Survey and Evaluation of Chemi-cal Warfare Agent Contaminants and Decontamination. DugwayProving Ground, Utah: Defense Technical InformationCenter; 1984. AD-202525. (2) Baker JA. Paper presented at:

COR Decontamination/Contamination Control Master PlanUsers Meeting; 1113 September 1985. (3) Joint RequirementsOffice for Chemical, Biological, Radiological and NuclearDefense.Joint Service Personnel / Skin Decontamination System(JSPDS). Washington, DC: Joint Requirements Office, 2004.


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TABLE 16-2

APPROPRIATE USES FOR MILITARY DECONTAMINANTS

Decontaminant Types of Patient DecontaminationStation (PDS)

When and Where Used

M291 Skin Decontamina-tion Kit

All types of PDS with limited wateror freezing temperature conditions

For dry decontamination of liquid chemical agentsonly; very useful if water is not available or ambi-ent temperature is freezing; used on skin andequipment

M295 Decontamination Kit All types of PDS with limited wateror freezing temperature conditions

For the dry decontamination of liquid chemicalagents only, used on equipment

Soap and water Used at all PDSs; the primarydecontaminant used at PDSs withplumbed tentage and on water ves-sels. It is very cost effective.

Used for

skin (copious amounts)

equipment (copious amounts)

washing down decontamination teamsTAP aprons and rinsing their gloves afterwashing with 5% bleach

best for washing away radiological, biologi-cal, and most chemical agents, but does notneutralize or kill them

0.5% hypochlorite (bleach)solution

PDSs with minimal equipment. Used on skin, also can be used to wipe down TAPaprons.

5% hypochlorite (bleach)solution

PDSs with minimal equipment: towash patient mask hood; decontam-ination team member gloves.

All PDSs: to soak cutting tools (chem-ical and biological agents only; forradiation use soap and water).

Used only on equipment, NOT skin. Not usedwith radiological agents. Used for chemical and

biological agents to

wipe down rubber mask hoods

wash gloves of patients and decontamina-tion team members (then rinse with freshwater)

fill pail for cutting tools

wash decontaminated litters (then rinsewith fresh water)

wipe down equipment (30 min contact time,then rinse)

Locally available absorbentmaterial:

clean sand baking powder fullers earth baby wipes flour

bread

other dry, non-

toxic, absorbentitems

Any PDS Used for the dry decontamination of liquid chemi-cal agents only on skin and equipment; used ifwater and M291 or M295 are not available orambient temperature is freezing.

Reactive skin decontamina-tion lotion (RSDL)

Any PDS Expected to replace or supplement the M291 kit.Used on skin and equipment for all types of agents.It wipes away contaminants and oximes and neu-tralizes some chemical agents and biological toxins.

PDS: patient decontamination stationTAP: toxicological agent protective


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the skin. They found that wiping the skin with a dryabsorbent object (such as paper, aseptic gauze, toiletpaper, or a towel) or covering the liquid with absorbentpowders, such as flour, talcum powder, diatomaceousearth, fullers earth, or Dutch powder (the Dutch varia-tion of fullers earth), and then wiping the residue off

with wet tissue paper were reasonably effective forremoving both nerve agent and mustards. Either pro-cedure had to be performed within 4 minutes, beforethe agent permeated the epidermis, to be maximallyeffective. The study also found that washing withsmall amounts of water or soap and water was effec-tive for removing nerve agents, but not effective formustard agents.45 Fullers earth and Dutch powderare decontamination agents currently fielded by someEuropean countries to absorb liquid agents.1

Developed to absorb and slowly neutralize liquidchemical agent, the M291 SDK (Figure 16-2) was firstissued to US forces in 1989 and is the current method

of battlefield decontamination used by individualservice members. The M291 kit was extensively testedin a rabbit model and proved effective for immediatedecontamination of skin.46,47 Recent studies in theclipped-haired guinea pig model, however, demon-

strated that the M291 SDK is only marginally effectiveagainst GD, GF, VX, and VR.48

The M291 SDK consists of a wallet-like carryingpouch containing six individual decontaminationpackets. Each packet contains a nonwoven, fiberfill,laminated pad impregnated with the decontamination

compounds: a carbonaceous adsorbent, a polystyrenepolymeric, and ion-exchange resins. The resultantblack powder is both reactive and adsorbent. Each padprovides the individual with a single-step, nontoxic,nonirritating decontamination application, which canbe used on intact skin, including the face and aroundwounds, but should not be used in wounds or onabraded skin.1 Instructions for its use are marked onthe case and packets. Small, dry, and easily carried,the M291 SDK is well suited for field use and is par-ticularly useful in areas where water is scarce. It isnot effective for removing dry chemical, biological,or radiological agents or for neutralizing them. Early

intervention with the use of this kit will reduce liquidchemical agent injury and save lives in most cases.

Packaged Wet Decontaminants

In 2004 the joint services established an operationalrequirements document to procure an effective skindecontaminant, referred to as the joint service per-sonnel decontamination system, that could be usedeffectively on the skin and eyes, around wounds,and on equipment against all CBRN agents as wellas other toxic industrial materials.49 In March 2007,

RSDL was selected as the joint service personneldecontamination system and is scheduled to replacethe M291 SDK.

RSDL is a bright yellow viscous liquid dispensedon a sponge that washes away chemical agent con-tamination (Figure 16-3). The lotion is a solution ofpotassium 2,3-butanedione monoximate and freeoxime in a mixture of water and polyethyleneglycolmonoethylether.11,50RSDL can be used to decontami-nate intact skin around wounds, but it is not approvedfor the decontamination of wounds or eyes. Testingat USAMRICD demonstrated that RSDL is superiorto the M291 SDK, 0.5% hypochlorite solution, and 1%

soapy water against a broad spectrum of chemicalagents.48 It was even effective against a 5medial-lethal-dosechallenge of VX when applied up to 25minutes after exposure.51 In addition to VX, RSDLneutralizes the effects of G agents, HD, and T-2 mi-cotoxin.52After breaking down the chemical agent ortoxin, it becomes a nontoxic liquid that can be washedfrom the skin with water.53RSDL is approved by theFood and Drug Administration as a medical device.54

Fig. 16-2. The six individual decontamination pads of theM291 kit are impregnated with the decontamination com-

pound Ambergard XE-555 resin (Rohm and Haas Co, Phila-delphia, Penn), a black, free-flowing, resin-based powder.Each pad has a loop that fits over the hand. Holding the padin one hand, the user scrubs the pad over contaminated skin.The chemicals are rapidly transferred into and trapped inthe interior of the resin particles. The presence of acidic and

basic groups in the resin promotes the destruction of trappedchemical agents by acid and base hydrolysis. Because theresin is black, the area that has been decontaminated is easyto see.


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The manufacturer (E-Z-EM Inc, Lake Success, NY)also produces a training stimulant (Figure 16-3[b])without oxime, packaged in a blue pouch, that allowsfor realistic training and the incorporation of humandecontamination into civil defense scenarios.

Chemical Decontaminants: Oxidation

Electrophilic reactions are the oxidative processesassociated with CWA detoxification. The most impor-tant category of chemical decontamination reactionsis oxidative chlorination. This term covers activechlorine chemicals (such as hypochlorite), which

under the proper conditions generate the positivelycharged chloride ion, a very reactive electrophile.The pH of a solution is important in determining theamount of active chlorine concentration; an alkalinesolution is advantageous. Hypochlorite solutions actuniversally against the organophosphorus and mus-tard agents.1,8

Both VX and HD contain sulfur atoms that are read-ily subject to oxidation. Current US doctrine specifies

the use of 0.5% sodium or calcium hypochlorite solu-tion for decontamination of skin and a 5% solution forequipment.1 Decontamination preparations such asfresh hypochlorite solution (either sodium or calciumhypochlorite) react rapidly with some chemical agents(eg, the half-time for destruction of VX by hypochloriteat pH 10 is 1.5 min), but the half-times of destructionof other agents such as mustard are much longer. If alarge amount of agent is initially present, more time isneeded to completely neutralize the agent.

Dilute hypochlorite (0.5%) is an effective skin de-contaminant for patient use. The solution should bemade fresh daily with a pH in the alkaline range (pH

1011). Plastic bottles containing 6 ounces of calciumhypochlorite crystals are currently fielded for this pur-pose.1 Dilute hypochlorite solution is contraindicatedfor the eye; it may cause corneal injuries. It also is notrecommended for brain and spinal cord injuries. Irriga-tion of the abdomen with hypochlorite solution, whichcan cause adhesions, is also contraindicated. The useof hypochlorite in the thoracic cavity may be less of aproblem, but the hazard remains unknown.1

Fig. 16-3.(a)Reactive Skin Decontamination Lotion (E-Z-EM Canada Inc, Anjou, Quebec, Canada) packets and (b)bluetraining packets.Photographs: Courtesy Lt Col Charles Boardman, US Air Force, US Army Medical Research Institute of Chemical Defense.

a b


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WOUND DECONTAMINATION

All casualties entering a medical unit after ex-periencing a chemical attack must be consideredcontaminated unless they have been certified as non-contaminated. The initial management of a casualty

contaminated by chemical agents requires removalof IPE and decontamination before treatment withinthe field MTF.

Initial Wound Decontamination

During thorough patient decontamination at apatient decontamination station, all bandages sus-pected of contamination are removed and the woundsare flushed with isotonic saline solution or water.Bandages are replaced only if bleeding begins afterdecontamination. Tourniquets suspected of beingcontaminated are replaced with clean tourniquets, and

the sites of the original tourniquets decontaminated.Both bandage replacement and tourniquet replace-ment are performed by medical personnel. Splintsare thoroughly decontaminated but removed onlyby a physician or under physician supervision. Oncethe patient has been thoroughly decontaminated andenters the medical facility, the new dressings are re-moved and submerged in 5% hypochlorite or sealedin a plastic bag.55

General Considerations

Three classes of chemical agent (vesicants, nerve

agents, and cyanide) might present a hazard fromwound contamination. Hydrogen cyanide is a blue-white liquid with a boiling point of 26C (79F). It canbe absorbed slowly through unbroken skin but muchmore rapidly through an open wound. Cyanide maybe delivered as pure hydrogen cyanide (liquid or gasdepending on temperature), pure solid salt (sodiumcyanide), or an aqueous solution of the metal salt.Cyanide is very toxic but less so than vesicants andnerve agents, and therefore less of a concern in openwounds.

Mustard converts to a reactive cyclic intermediatecompound within a few minutes of absorption intoa biological milieu, and the cyclic intermediate reactsrapidly (within a few minutes) with blood and tissuecomponents.13 In a wound, the compound reacts withblood, the necrotic tissue, and the remaining viabletissue. If the amount of bleeding and tissue damage issmall, mustard will rapidly enter the surrounding viabletissue, where it will quickly biotransform and attach totissue components, and its biological behavior will besimilar to an intramuscular absorption of the agent.

Although nerve agents cause their toxic effects byvery rapid attachment to the enzyme acetylcholin-esterase, they also quickly react with other enzymesand tissue components. As with mustard, the blood

and necrotic tissue of the wound buffers the nerveagents. Nerve agent that reaches viable tissue will berapidly absorbed, and because of the high toxicityof nerve agents (a small fraction of a drop is lethal),casualties with wounds contaminated by liquid nerveagent are unlikely to reach medical care alive.56Thepotential risk from contaminated wounds arises fromchemical agent on foreign bodies in the wound andfrom thickened agents.57

Thickened Agents

Thickened agents are chemical agents mixed with

another substance (commonly an acrylate) to increasetheir persistency. They do not dissolve as quickly inbiological fluids, nor are they absorbed by tissue asrapidly as other agents. (VX, although not a thickenedagent, is absorbed less quickly and may persist in awound longer than other nerve agents.) Thickenedagents are not known to be stockpiled by any country.In a chemical attack, the intelligence and chemical staffshould be able to identify thickened agents and alertmedical personnel of their use.

Casualties with thickened agents in wounds (eg,from pieces of a contaminated battle-dress uniform orprotective garment being carried into the wound tract)

require more precautions and are unlikely to surviveto reach surgery. Thickened mustard has delayed sys-temic toxicity and can persist in wounds even whenlarge fragments of cloth have been removed. Althoughthe vapor hazard to surgical personnel is low, contacthazard from thickened agents remains and shouldalways be assumed.56

Foreign Material and Off-Gassing

The contamination of wounds with mustard, nerveagents, or cyanide is mostly confined to the pieces ofcontaminated fabric in the wound tract. The removalof this cloth from the wound effectively eliminatesthe hazard. Little chemical risk is associated withindividual fibers left in the wound. No further decon-tamination of the wound for un-thickened chemicalagent is necessary.56Cooper et al56 reported that therisk from vapor off-gassing of chemically contaminatedfragments and cloth in wounds is low or nonexistent,and that off-gassing from a wound during surgicalexploration is negligible. Eye injury is not expected


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from off-gassing from any of the chemical agents, andchemical-protective masks are not required for surgi-cal personnel. However, recent studies58indicate thatswine exposed to 400 L of neat HD continue to off-gasup to 48 hours postexposure.

Wound Exploration and Debridement

No single glove material protects against everysubstance. Butyl rubber gloves generally providebetter protection against chemical warfare agentsand most toxic industrial chemicals (but not all) thannitrile gloves, which are generally better than latexsurgical gloves. Surgeons and assistants are advisedto wear two pairs of gloves44: a nitrile (latex if nitrileis not available) inner pair covered by a butyl rubberouter pair. Thicker gloves provide better protectionbut less dexterity. Latex and nitrile gloves are gener-ally 4 to 5 mils thick (1 mil = 1/1,000 of an inch). The

recommended butyl rubber glove is 14 mils thick; ifgreater dexterity is needed a 7-mil butyl glove may beworn. A study at the US Army Soldier and BiologicalChemical Command59showed breakthrough times forHD and GB depended on glove material and thick-ness. N-Dex (Best Manufacturing, Menlo, Ga) nitrilegloves (4 mil) had a breakthrough time of 53 minutesfor HD and 51 minutes for GB. North (North SafetyProducts, Cranston, RI) butyl gloves (30 mil) had abreakthrough time of over 1,440 minutes for both HDand GB. The safety standard operating procedure atUSAMRICD60for working with neat agents requiresa maximum wear time of 74 minutes for HD and 360

minutes for G agents and VX when wearing 7-mil butylrubber gloves over 4-mil N-Dex nitrile gloves. Wearingthis glove combination is recommended until usersascertain that no foreign bodies or thickened agentsare in the wound. Double latex surgical gloves have nobreakthrough for 29 minutes in an aqueous medium;they should be changed every 20 minutes61(changinggloves is especially important when bone spicules ormetal fragments can cause punctures).56

The wound should be debrided and excised as usual,maintaining a no-touch technique (explore the woundwith surgical instruments rather than with the fingers).Pieces of cloth and associated debris must not be exam-ined closely but quickly disposed of in a container of5% hypochlorite. Recent studies at USAMRICD by Gra-ham58demonstrated significant off-gassing during laser

debridement of HD-exposed skin in swine. Removedfragments of tissue should be dropped into a containerof 5% to 10% hypochlorite. Bulky tissue such as anamputated limb should be sealed in a chemical-proofplastic or rubber bag.56Penetrating abdominal woundscaused by large fragments or containing large pieces

of chemically contaminated cloth will be uncommon.Surgical practices should be effective in the majorityof wounds for identifying and removing the focus ofremaining agent within the peritoneum.

Cooper et al56 suggest checking a wound withan ICAM, which may direct the surgeon to furtherretained material. However, this process is slow (astable reading takes about 30 seconds; a rapid passover the wound will not detect remaining contamina-tion) and is not effective unless vapors are emanatingfrom wound debris. A single bar reading on an ICAMwith the inlet held a few millimeters from the woundsurface indicates that a vapor hazard does not exist;

more than one bar is needed to indicate a vapor hasbeen detected.56

Dilute hypochlorite solution (0.5%) should not beused to flush wounds. Isotonic saline or water may beinstilled into deep, noncavity wounds following theremoval of contaminated cloth. Subsequent irrigationwith saline or other surgical solutions should be per-formed.1 Saline, hydrogen peroxide, or other irrigatingsolutions do not necessarily decontaminate agents butmay dislodge material for recovery by aspiration witha large-bore suction tip. The irrigation solution shouldnot be swabbed out manually with surgical sponges;rather, it should be removed by suction to a disposal

container and handled like other agent-contaminatedwaste within a short time (5 min). Although the riskto patients and medical attendants is low, safe practicesuggests that any irrigation solution should be consid-ered potentially contaminated. Following aspiration bysuction, the suction apparatus and the solution shouldbe decontaminated in a solution of 5% hypochlorite.Superficial wounds should be subjected to thoroughwiping with normal saline or sterile water.1

Instruments that have come into contact with possi-ble contamination should be placed in 5% hypochloritefor 10 minutes before normal cleansing and steriliza-tion. Reusable linen should be checked with the ICAM,M8 paper, or M9 tape for contamination. If found tobe contaminated, the linen should be soaked in a 5%to 10% hypochlorite solution or discarded.1

PATIENT THOROUGH DECONTAMINATION

Need

The focus of patient decontamination is identical

throughout the services and in the civilian sector: itis the removal of hazardous substances from the con-taminated individual to protect that person and sub-


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sequently reduce the incidence of cross contaminationto others. Early removal of the hazardous substanceis key to significantly reducing the dose of agent anindividual is exposed to. When early removal (withinthe first 15 minutesideally within the first 2 minutes)is not possible, later removal can reduce the effects

from a chemical agent but to a lesser degree. Removalat any time reduces the threat that others may be cross-contaminated. Patient thorough decontamination, per-formed before allowing a contaminated patient insidethe confines of a hospital, provides two benefits. First,it can potentially reduce the dose the patient receives,and, second, it protects hospital staff from exposure tothe hazardous agent and its vapors.

In the United States, healthcare workers are the 11thmost common group injured in hazardous materialsincidents, but injury to emergency department work-ers is even more infrequent, only 0.2% of some 2,562events from 1995 to 2001 documented in the Agency

for Toxic Substances and Disease Registry HazardousSubstance Emergency Events Surveillance System.44Inthese instances, the injured workers were not wearingrespiratory protection and suffered eye and respiratorytract irritation.62

Several studies and reports illustrate the need for thethorough decontamination of patients before hospitaladmission. Okumura et al63published a survey of thestaff of Saint Lukes International Hospital in Tokyo.This facility was closest to the Tokyo subway sarinrelease and received 640 patients, the largest numberof victims from the event. The study indicated that 110staff members, 23% of the 472 medical personnel in the

hospital at the time, reported acute poisoning symp-toms including headache, blurred vision, dyspnea,nausea, and dizziness. None of the staff at this facilitywore respiratory protection, and none of the patientswere decontaminated in any way. Particularly affectedwere staff working in the hospital temporary triagearea, which was located in the poorly ventilated hos-pital chapel, and those in the intensive care unit. 63

Nozaki et al64 conducted a retrospective studyof care providers at another facility, the UniversityHospital of Metropolitan Japan, who also attended tosubway victims. Of the 15 physicians who worked inthe emergency room, none wore any protective equip-ment; 13 became aware of symptoms of exposure whileresuscitating two of the casualties. Eleven of thesedoctors complained of dim vision lasting several days,and eight showed significant miosis (pupils < 2 mm).Eight had rhinorrhea (runny nose), four had dyspnea(shortness of breath or tightness of the chest), and twohad a cough. Six of the symptomatic care providerswere given atropine sulfate, and one, who had morepredominant dim vision than the others, was also

given pralidoxime methiodide. Subsequent removal ofthe patients contaminated clothing and ventilation ofthe emergency room helped reduce exposure.64Table16-3 summarizes the signs and symptoms displayedby medical personnel at St Lukes and Universityhospitals.

Similarly, reports by Foroutan65

indicate that unpro-tected medical staff caring for contaminated Iranianvictims of an Iraqi poison chemical gas bombardmentalso became ill. In one instance, a doctor and a nurseproviding patient resuscitation in a busy treatment areabecame dizzy, were short of breath, and had severeheadaches and cough. Within 5 minutes the remainderof the medical staff in the emergency room developedthe same symptoms, could no longer stand up, and hadto sit on the floor. The staff was evacuated to anotherhospital and the emergency room closed and ventilatedfor 3 hours. In this case both cyanide antidotes andlater atropine were administered, which reduced the

providers symptoms.65Another documented relevant example took place

in 2001 in the emergency room of a hospital in an agri-cultural area of Great Britain. Pesticides are among thetop choices for those committing suicide and homicide,particularly in agricultural regions of the world.66Aman who attempted suicide by ingesting an organo-phosphate pesticide was brought into the emergencyroom, where he vomited, causing a chemical spill. Theincident caused 25 hospital workers to seek medicalattention, and 10 complained of symptoms indicativeof toxic exposure.67These events illustrate the impor-tance of thorough decontamination for contaminated

patients, prompt clean-up of pesticide-tainted vomit,and adequate protection, particularly respiratory pro-tection, for hospital workers when vapor hazard fromcontamination exists.

Personnel

Patient thorough decontamination operations arepersonnel intensive. Typically from 7 to 20 person-nel are needed to staff decontamination teams, notincluding medical treatment personnel. In the mili-tary, with the exception of the US Air Force and someship-based units that deploy trained patient decon-tamination teams composed of medical personnel, themilitary patient decontamination process is carriedout by nonmedical augmentees supervised by trainedmedical personnel.3In the civilian sector gross decon-tamination is often performed by fire departments orhazardous materials (HAZMAT) teams, and thoroughdecontamination at medical facilities is carried out byhospital personnel assigned to perform the job as anadditional duty.2,68


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Close medical monitoring and treatment of ca-sualties before, during, and after thorough decon-

tamination must be an integral part of all patientdecontamination operations. Medical conditions canchange as individuals undergo the stressful process ofdecontamination. If the exposure is to a liquid agent, itmay take time for the agent to transit the skin layers. Apatient exposed to a liquid chemical agent may appearstable or well during decontamination but can becomeworse during or after the decontamination process.

Decontamination Operator Protection

Heat and musculoskeletal injury are primary con-cerns for decontamination team members. Individualsmust perform heavy work (patient treatment, triage,and litter movement) while wearing IPE. Working ina hot environment lowers individual mental alertnessand physical performance. Increased body temperatureand physical discomfort can cause workers to overlooksafety procedures or divert their attention from hazard-ous tasks. These critical issues must be addressed beforeand throughout decontamination operations.

Musculoskeletal injury can occur from lifting

patients, carrying litters, or falling while wearingprotective ensemble. Injury reduction strategies such

as removing tripping hazards, policing the decon-tamination area for debris, working at a safe pace,rehearsing ergonomically correct patient lifts, enforc-ing frequent rest breaks, using special equipment toreduce lifting (such as wheeled litter carriers), andinsuring adequate staffing are all useful strategies toprevent worker injury.

The chemical protective ensemble prevents an indi-viduals sweat from readily making contact with theair, which inhibits heat transfer from the body, makingit difficult for the body to cool itself, which can leadto heat injury. The National Institute for OccupationalSafety and Health publication Working in Hot Environ-ments describes a variety of heat conditions includingheat stroke (the most life threatening), heat exhaustion,heat cramps, fainting, heat rash, and transient heat fa-tigue.69All decontamination personnel must be trainedin preventative measures for these conditions, be ableto identify their signs and symptoms, and know whatto do when they occur. It typically takes humans 5 to7 days to adjust to working in hot temperatures. Heatstress can be reduced by reducing prolonged exposure

TABLE 16-3

SIGNS AND SYMPTOMS REPORTED BY TOKYO HOSPITAL WORKERS TREATING VICTIMS OFSARIN SUBWAY ATTACKS*

Symptom Number/percentage of the 15 physicianswho treated patients at UH

Number/percentage of 472 care providersreporting symptoms at SLI

Dim vision 11 73% 66 14%

Rhinorrhea 8 53% No information

Dyspnea (chest tightness) 4 27% 25 5.3%

Cough 2 13% No information

Headache No information 52 11%

Throat pain No information 39 8.3%

Nausea No information 14 3.0%

Dizziness No information 12 2.5%

Nose pain No information 6 1.9%

*Data reflect reported survey of self-reported symptomatology of physicians at the University Hospital of Metropolitan Japan emergencydepartment and all hospital workers at Saint Lukes International Hospital exposed to sarin vapors from victims of the Tokyo subway at-tack.SLI: Saint Lukes International HospitalUH: University HospitalData sources: (1) Nozaki H, Hori S, Shinozawa Y, et al. Secondary exposure of medical staff to sarin vapor in the emergency room. IntensiveCare Med. 1995;21:1032-1035. (2) Okumura T, Suzuki K, Fukuda A, et al. The Tokyo subway sarin attack: disaster management, Part 1: com-munity emergency response. Acad Emerg Med.1998;5:613-617. (3) Okumura T, Suzuki K, Fukuda A, et al. The Tokyo subway sarin attack:disaster management, Part 2: Hospital response. Acad Emerg Med.1998;5:618-624.


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EXHIBIT 16-4

ZONES OF CONTAMINATION

Hot zone: Area of agent release that is directly con-taminated.

Warm zone(or decontamination zone): Area outsidethe hot zone where contamination consists only of that

brought into the area by contaminated patients andworkers from the hot zone.

Cold zone (postdecontamination zone): Area beyondthe warm zone that is free of solid, liquid, and vaporcontamination. Patients are decontaminated beforeentering this area.

workload among team members. Failure to enforceappropriate workrest cycles increases the risk ofinjury and ultimately depletes personnel pools onsubsequent days. Workrest cycles insure adequatehydration, give the body an opportunity to disperse ex-

Individual Protective Equipment

All decontamination team members must wear IPEfor their protection.3,44OSHA and the Federal ChemicalStockpile Emergency Preparedness Program recom-mend OSHA level C as the most appropriate wearfor first receivers, which include decontaminationteam members.44,70,71In the military, MOPP level 4 isroughly equivalent to OSHA level C. OSHA levels Aand B (Exhibit 16-3) are normally worn at an incidentsite (hot zone; Exhibit 16-4) when the contamination is

unknown. This high level of protection, which createsan additional heat burden on the worker and restrictsmobility, is not necessary for decontamination op-erations in the warm zone, where the chemical risk isgreatly reduced. For more information on OSHA levelssee Chapter 17, Chemical Defense Equipment.

Decontamination team members using dry de-contaminants, water, soap and water, or other liquiddecontaminants must wear IPE that allows for easyoperator wipe down. The IPE must also preventundergarments from being saturated with water ifwater is used during decontamination. Torngren etal72showed that aerosolized agent simulants and their

vapors penetrate protective equipment that becomessaturated with water during patient decontamination

cessive heat, and slow down the production of internalbody heat created during physical work. Chapter 14,Field Management of Chemical Casualties, providesfurther discussion on workrest cycles and a table forcalculating them.

EQUIPMENT FOR PATIENT THOROUGH DECONTAMINATION

Fig. 16-4. An example of a hooded, powered air pressurerespirator with a Tyvek F [(DuPont, Wilmington, Del) over-garment. Note the filter power unit worn at the waist.Photograph by Peter Hurst, US Army Medical ResearchInstitute for Chemical Defense.

operations.72In this study, the wet underwear of thedecontamination operators became contaminated.Preventing this saturation is best accomplished by


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wearing a butyl rubber toxicological agent protectiveapron over IPE or wearing IPE that is impermeableto water (eg, Tyvek F [DuPont, Wilmington, Del]).These impermeable garments, however, increasethe heat load on the worker. Protective aprons serveseveral purposes: they allow team members to easily

decontaminate themselves between patients, keepundergarments free from contaminated moisture, andallow workers the option to remove this layer and moreeasily cool themselves in a rest area.

Military decontamination team members may wearthe standard military M40 series, MCU2P, or new jointservice general-purpose mask (see Chapter 17, Chemi-cal Defense Equipment, for more information). An al-ternative is to wear a powered-air purifying respirator,which has a blower motor that pulls air through filtersand into the mask hood (Figure 16-4). The circulatedair blown into the mask hood helps keep the wearercool, eliminates the effort to inhale air through filters,

and reduces carbon dioxide buildup in the mask dur-ing heavy work. Produced by several companies, thesemasks must be rated at a protective factor of 1,000, perOSHA first receiver guidance, and should be approvedby the National Institute of Occupational Safety andHealth.44OSHA also dictates that all individuals mustbe medically cleared to wear full-face protective masksand equipment.73A variety of voice amplifiers that fitto the mask, throat or voice-activated microphones thatwork with head-mounted radios, and other types ofcommunications systems that improve communica-tion with mask use are available on the market.

Transport Equipment

Only litters or backboards made of plastic materialthat can be readily and thoroughly decontaminatedshould be used to hold contaminated patients. Clothlitters will hold agent, cannot be decontaminated effec-tively, and rapidly deteriorate when decontaminatedwith bleach solution.

Detection Devices

Detectors and monitors can be used at the arrivalpoint, to assess which patients require decontamina-tion, or after the decontamination process, to check forthoroughness of decontamination. In some instancesthe thoroughness of the decontamination process maymake detectors less necessary (for example, whenplumbed tent systems are used and ample suppliesof soapy water and rinse water are available). Theuse of detectors is dictated by unit operating plansand specific service concepts of operation and tactics,techniques, and procedures.

Currently fielded chemical warfare agent detectionand monitoring equipment does not identify all pos-sible CWAs or toxic industrial chemicals (see Chapter17, Chemical Defense Equipment for more detail).Existing military chemical detectors that can be usefulduring patient decontamination operations include M8

chemical detector paper, M9 chemical detector paper,the ICAM, the M22 automatic chemical agent detectoralarm, and the HAPSITE Smart Chemical IdentificationSystem (INFICON, East Syracuse, NY).55

Decontamination Shelters

Decontamination equipment varies from the simpleuse of buckets and sponges, or the use of fire trucks tospray down victims, to the more complex deploymentof pop-up shelters or patient decontamination systemsbuilt on existing medical facilities. The variety of de-contamination equipment has dramatically expanded

since the terrorist events of September 11, 2001. Mostdecontamination systems use soap and water as theprimary decontaminant. Some examples are shownin Figures 16-5 through 16-7. Shelters differ in con-struction, method of erection, plumbing, and systemfor moving litters. All of these factors can impact onoverall system weight, durability, ease of set-up andtear down, and shelter footprint.

Decontamination shelters are useful for a variety ofreasons. They protect decontamination workers andpatients from wind and poor weather conditions, aswell as providing privacy for patients during the de-contamination process. Shelters provide a framework

to support built-in plumbing, which makes set-upand processing of patients faster and easier than usingbuckets and sponges. Some degree of water pressure isnecessary to operate the systems. Each system require-ment is different, but the ideal system incorporates ahigh volume of water at low pressure.2Air and waterheaters should be added to improve patient comfort.Roller systems can be incorporated to more rapidlyprocess litter patients while reducing the incidenceof musculoskeletal injuries among decontaminationworkers. Roller systems also reduce the number ofworkers necessary to perform decontamination proce-dures. A crew of 12 is recommended by the Air Forcefor decontamination shelter operations, but the processcan be performed with a staff (not including medicalpersonnel) of four individuals for the litter line, onefor the ambulatory line, and two for the clean (cold)side of the hot line (or liquid control line).74,75Moreindividuals, encompassing several shifts, are neededto insure adequate rest cycles to reduce injury to de-contamination operators. A variety of roller systemsthat differ in weight, ease of portability, and ease of


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Fig. 16-5.TVI (TVI Corporation Inc, Glenn Dale, Md) decon-tamination pop-up shelter consisting of a light-weight scissorframe tent, integrated plumbing, heater, water bladder, and

quickly expandable light-weight roller system with back-board. It can easily be erected within a few minutes by twoindividuals. Shown is a small size tent. Can be configuredfor both ambulatory and litter patients.Photograph: Courtesy TVI Corporation.

Fig. 16-6. A medium sized Reeves DRASH (deployable rapidassembly shelter). The scissors construction allows for tentexpansion similar to the TVI tent but with the framework on

the inside of the shelter. It also has integrated plumbing anda litter roller system. Can be configured for both ambulatoryand litter patients.Photograph: Courtesy of Lt Col Charles Boardman, US AirForce, US Army Medical Research Institute of ChemicalDefense. Reproduced with permission from Reeves EMSLLC, Orangeburg, NY.

Fig. 16-7.The US Armys method of using litter stands, buckets, and sponges. This process requires more frequent lifting ofpatients and water buckets than shelters with roller systems. The advantage, on the battlefield, is that this decontaminationequipment is easy to carry. Ample quantities of water are still needed unless dry decontamination is used. This method iscurrently preferred by Army field units that cannot carry large quantities of equipment.Photographs: Courtesy of Lt Col Charles Boardman, US Air Force, US Army Medical Research Institute of Chemical Defense,and Peter Hurst, US Army Medical Research Institute of Chemical Defense.

assembly are on the market.OSHAs recommended best practice for fixed fa-

cilities such as hospitals is to build decontaminationfacilities outside the building or near the emergencyentrance.44Fixed decontamination facilities allow forimmediate decontamination of casualties because no

set-up time is required. A well trained crew can typi-cally set up a pop-up decontamination shelter in 10to 20 minutes, depending on the type of equipmentused.76For units expected to assist in decontamina-

a b


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tion operations near an incident site, pop-up sheltersor covered configurations of fire trucks that allow for

privacy and some protection from the elements arepreferred.

ESTABLISHING A PATIENT THOROUGH DECONTAMINATION AREA

Patient thorough decontamination areas are es-

tablished in locations considered to be free fromcontamination. Once contaminated patients arrive,these areas become designated as warm areas becauselow levels of dry, liquid, and vapor contaminationmay be brought in on the clothing, equipment, hair,and skin of patients admitted to the area. The directhazard to workers is much reduced compared to thehot zone, but decontamination team members mustwear protective ensemble because vapors and par-ticles, even in small amounts, pose a hazard to thoseworking directly with the contaminated patients. Formore information on zones of contamination and therelationship of the decontamination area to triage and

treatment areas see Chapter 14, Field Management ofChemical Casualties.

Water Concerns

Decontamination operations may use dry decon-taminants, such as the M291 kit or diatomaceous earth;prepackaged wet decontaminants such as RSDL; soapand water; or chemical decontaminants such as 0.5%hypochlorite solutions. Critical to operations usingsoap and water is the availability of an adequatesupply of water and a way to collect waste waterrun-off. Water trucks or water buffalos are neededfor locations where water is scarce and fire hydrantsare not available. In an urban setting, such as thecivil response to a homeland incident, ample wateris usually available through access to fire hydrants.Water is typically, however, not easily available in abattlefield situation.

If casualties are wearing full MOPP ensemble, as ina battlefield environment, the need for a comprehen-sive washing of the whole body is reduced, becausemuch of the body is protected by the IPE. Casualtieswithout protective clothing will have greater dermalexposure, because liquid chemical agents penetrate

regular clothing, and subsequently will usually re-quire washing of the whole body.The disposition of waste water is an issue both on

the battlefield and during homeland operations. Fail-ure to contain contaminated waste water will pollutean area and prevent its later use. Federal regulationsthat apply to homeland operations in emergency situ-ations allow for water run-off, as long as the actionis not performed intentionally as a way of ignoringwaste disposal regulations. Environmental Protection

Agency regulation 550-F-00-009,77which addresses

first responder liability to mass decontaminationrun-off, considers the release of chemical or biologicalwarfare agents from a terrorist event to be the sameas a HAZMAT event and therefore covered under theComprehensive Environmental Response, Compen-sation, and Liability Act of 1980, section 107.77Thisact notes that under the good Samaritan provision,which would apply to emergency response HAZMAToperations, No person shall be liable under this subchapter for costs or damages as a result of actionstaken or omitted in the course of rendering care, as-sistance, or advice in accordance with the NationalContingency Plan or at the direction of an on-scene

coordination with respect to an incident creating adanger to public health or welfare or the environmentas a result of any release of a hazardous substance orthe threat thereof.77

The decontamination of patients with largeamounts of water is expected to result in waste wa-ter run-off containing a minimal concentration ofchemical agent.78 Currently most response agencieshave received funding to purchase adequate decon-tamination equipment, which would include the useof waste water containment systems. In the UnitedStates in particular, failure to use these systems couldbe seen as negligence, if a response agency washed

contamination down a sewer as an alternative toavoiding the extra costly and sometimes problem-atic effort of appropriate waste water collection anddisposal using containment berms and bladders.The provisions cited above do not protect an agencyagainst failing to develop a plan for collection anddisposal of contaminated water during an incident.Plans may be overcome by events, but if no plansexist, a unit could be liable for damages. Even whenprotected by the Comprehensive Environmental Re-sponse, Compensation, and Liability Act, agencies canstill be sued by state agencies, private agencies, andprivate individuals or groups. Tort reform is differentin each state, so it is important for response agenciesto participate in their local area planning committeeearly to work out these issues in writing.77 It is criticalthat military units responding to homeland eventsfollow these guidelines.

Training exercises should be used to determine thenumber of waste water bladders needed for expectedmass casualty decontamination operations. If bladdersare filling during exercises, additional ones should


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be purchased. Decontaminating one individual isestimated to take 10 gallons of water, so a 200-gallonwater bladder will become full sometime during thedecontamination of the 20th patient. Bladders in avariety of sizes are made by several manufacturers;some models are now available with handles that can

be lifted onto a truck. Site plans should include thestaging of additional bladders so that an empty blad-der is always available when needed. Training waterdecontamination crews to turn off water sprayerswhen they are not needed will keep bladders fromfilling as quickly. Procedures for cleaning bladdersand disposing of waste material should be practiced.Written contracts should be made with hazardouswaste disposal agencies before an incident occurs.

Handling Patients

Writings by Foroutan65and others63,79note the im-

portance of triage and treatment to stabilize patientsbefore they undergo more thorough decontamina-tion. Medical facilities must also be prepared forwalk-in contaminated casualties who have bypassedemergency response teams. These patient triage andtreatment areas should be established at the frontof patient thorough decontamination operations.Decontamination can take time, typically from 10 to20 minutes for litter patients and at least 5 minutesfor ambulatory patients. In mass casualty situationsmedical personnel will be needed to manage patientsawaiting decontamination. Because patients can alsobecome medically unstable during decontamination,

medical personnel are also needed to follow patientsthrough the decontamination line.

Whether shelters, fixed facilities, or buckets andsponges are used, the thorough decontaminationprocess is similar: patient arrival, triage, medicalstabilization, securing of personal effects, clothingremoval, washing, checking for any remaining con-tamination (where dictated), crossing the hot line,drying and re-clothing or covering the patient, andfinally disposition of the patient to the medical treat-ment area on the clean side of the hot line. See Chapter14, Field Management of Chemical Casualties, formore information.

Removal of contaminated IPE from patients shouldbe done by carefully cutting and rolling the ensembleaway from the patients underclothing and skin. Thisprocess helps to contain any agent on the garment andprevents cross contamination of the patients under-garments and now unprotected skin. If the patientis not wearing protective clothing, the containmentof contamination is not as critical, and the clothingshould be cut off as quickly as possible. During a

suspected terrorist incident, clothing should be indi-vidually bagged and labeled for forensic investigationby law enforcement agencies.

Sharp, long-handled seat belt cutters (not listedin medical equipment sets) and bandage scissors areideal for quickly cutting off clothing and IPE; however,

they typically become dull after cutting three to fivegarments, so operators should have a dozen or more ofeach cutter available (placed in a bucket of 5% bleach).To reduce the possibility of cross contamination, thecutting tools should be dipped into the bleach or ex-changed after every long cut.

Additionally, litters used on the warm side shouldnot cross the hot line. Rather, the patient is transferredto a clean litter at the hot line, and the warm-side litteris cleaned and reused. This process further reducesany cross-contamination hazard. Medical informa-tion should be transferred from contaminated patienttriage cards to clean ones as the patient is moved

across the hot line. A variety of patient card systemsare available. In the battlefield, the military currentlyuses the field medical card (DD Form 1380).

Night Operations

Night operations make patient triage, treatment,and decontamination more challenging. Floodlightsare not appropriate in a battlefield situation whereblackout conditions are imposed, but in a noncom-bat environment their use should be encouragedto enhance visibility. Also, fluorescent light sets areavailable for use inside decontamination shelters to

improve visibility.To reduce the incidence of accidents under light-

restricted conditions, decontamination lanes shouldbe set up during daylight hours, if possible. The lanesshould be clearly marked with reflective tape or waist-high, hanging chemical lights that glow in the dark.Lanes must be kept free from debris and should befamiliar to litter bearers. Effective traffic control andoff-load procedures are critical at the arrival point toprevent vehicles from hitting patients or operators.

To help identify personnel, operators should havetheir names and job clearly marked on the front andback of their protective ensemble. If available, reflec-tive vests are ideal and serve to both enhance visibil-ity and identify personnel. Voice amplifiers or othercommunication devices fitted to protective masks willhelp communications. Adequate flashlights, with redlens filters, are essential for operators during tacticalscenarios.

Night operations require careful planning and ad-ditional resources; even in optimal weather conditionssuch operations pose great challenges. To minimize


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the challenges and risks associated with night op-erations, leaders should develop night plans to meettheir organizational mission objective and train their

personnel accordingly. These plans should then beincorporated into the organizations tactical standingoperating procedures.

DECONTAMINATION IN COLD WEATHER

Although cold temperatures can decrease the ef-fectiveness of deploying some chemical agents, vari-ous chemical formulations have been developed forcold-weather use, such as Lewisite, which can remaina liquid at freezing temperatures. A more realisticthreat today is the purposeful or accidental release ofhazardous industrial chemicals during cold weather.Accidents of this type regularly occur in the UnitedStates through ground and rail transportation mishaps,such as the January 2005 train derailment in Granite-ville, South Carolina, which released chlorine gas.80Ona cold day, chemical agents can also be dispersed inwarm areas such as buildings. In the event of a building

evacuation, casualties might be required to report toan outside assembly area or decontamination station.Additionally, nighttime temperature drops and rainyconditions produce reduced temperature situationseven in warm climates.

Cold Shock and Hypothermia

Cool temperatures greatly increase the risk of coldshock and hypothermia.81Cold shock occurs when anindividual is suddenly exposed to cold temperatures,

such as cold water in a decontamination shower.

82

Cold shock can cause death by triggering peripheralvasoconstriction, a gasp reflex, hyperventilation, andrapid heart rate leading to heart failure.83 Casualtieswho are medically compromised, elderly, or haveheart disease are particularly at risk. Hypothermia,though less of a threat than cold shock, occurs whenthe body core temperature drops below its normal98.6F (37C) range.82

Giesbrecht, who studied hypothermia extensively,identified its symptoms and stages (Table 16-5).83Mildhypothermia begins when victims are no longer ableto shiver and their motor responses begin to become

impaired. A narrow window of only 7C (13F) belownormal core body temperature exists before severehypothermia can develop. A rapid drop in core bodytemperature will occur in patients who are alreadymedically compromised (eg, have symptoms of chemi-cal agent exposure or coexisting traumatic injuries).Trauma itself causes hypothermia.84 Those with hy-pothermia who are already medically compromisedare at much higher risk of death than those who arenormothermic.85,86The use of benzodiazepines (eg,diazepam), the anticonvulsant for exposure to nerve

TABLE 16-5

STAGES AND SYMPTOMS OF HYPOTHERMIA

Stage Core Temp Status Symptoms

C F

Normal 35.037.0 95.098.6 Muscle and mental control and respons-es to stimuli fully active.

Cold sensation; shivering.

Mild 32.035.0 89.695.0 Physical (fine and gross motor) andmental (simple and complex) impair-ment.

Moderate 28.032.0 82.489.6 Muscle and mental control and re-

sponses to stimuli reduced or cease tofunction.

At 86F (30C) shivering stops, loss of

consciousness occurs.

Severe < 28.0 < 82.4 Responses absent. Rigidity; vital signs reduced or absent;risk of ventricular fibrillation/cardiacarrest (especially with rough han-dling).

< 25.0 < 77.0 Spontaneous ventricular fibrillation; cardiac arrest.

Data sources: (1) Giesbrecht GG. Pre-hospital treatment of hypothermia. Wilderness Environ Med. 2001;12:24-31. (2) US Army Soldier andBiological Chemical Command. Guidelines for Cold Weather Mass Decontamination During a Terrorist Chemical Agent Incident. Revision 1. Ab-erdeen Proving Ground, Md: SBCCOM; 2003.


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agents, can cause an acute and transient hypothermia.87

Individuals in wet clothing, or those who are station-ary, will lose body heat more rapidly. Heat is conductedout through cool, damp clothing,88and wind convec-tion against wet skin also facilitates rapid body coolingand, in cooler temperatures, hypothermia.89

Those who are not medically compromised cantolerate ambient temperatures down to 65F (18.3C)for several minutes. Colder ambient temperatures,however, are uncomfortable and may cause shivering.Shivering, although it heats the body and is a sign ofhealthy thermoregulation, is very uncomfortable anddepletes a patients available energy stores.

Protection for Decontamination Team Members

Cold climates reduce the risk of heat injury for de-contamination team members, but heat injury can occurif individuals wear excessive thermal undergarments

under their protective ensemble and fail to anticipatethe heat their bodies generate once they begin working.Cold injuries also

chapter 16 - decontamination of chemical causal ties - pg. 527 - 558

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