Medical Aspects of Chemical Warfare (2008) - The Black Vault

Decontamination of Chemical CasualtiesDel) were observed to show appreciable solubility.SERPACWA is now a standard issue item to US forcesfacing a threat of CWA use.FunctionSERPACWA is an antipenetrant barrier cream foruse by service members to protect against the toxic effectsof 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.EffectivenessSERPACWA 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 neutralizeCWAs into less toxic products.ApplicationSERPACWA is used at the direction of the commander.Each service member is issued six packets ofSERPACWA, sufficient material for six applications orfor 2 days of use. Its effectiveness depends on the thicknessand 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 dissipateheat. Under normal conditions, SERPACWA iseffective when spread over the skin as a thin layer (0.1mm thick, or 0.01 mL/cm 2 ). 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 withoutbrushing 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 coatingbecomes embedded with particulate matter (dirtor sand), if the sites are decontaminated, or after 8hours 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 effectiveness.If DEET is wiped off before application using adry towel, gauze, or piece of cloth, SERPACWA canstill provide significant protection.Effects on DecontaminationThe use of SERAPCWA makes decontaminationeasier in areas protected by the barrier. It is easier tophysically remove CWA from a SERPACWA layer thanfrom the skin. Service members should still performskin decontamination immediately after chemicalcontamination, because SERPACWA’s 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 fromcontacting the paper).Active Barrier CreamsIn 1994, to overcome the limitations of SERPACWA,USAMRICD began development of an improved substancethat 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 researcherswere 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 neutralizeCWA. Reaction mechanisms that do not involvecharged transition states are favored in this medium.The improved SERPACWA containing a reactive matrixbecame known as active topical skin protectant(aTSP). Four criteria were established for aTSP: (1) the531