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4. Decontamination of Chemically Contaminated Remains
Keywords
US DodMACRMSC-CHRCWASwine Contaminated Remains Hazard (VX)Introduction
“Our government has a solemn promise, and it’s a sacred trust…We will not forget our fallen heroes. We will recover them. We will bring them home…A mother never forgets her son. The tears are as real today as they were 50 years ago. That was her son, and he was lost in combat, and she wants him home.” These words were spoken by a senior US Department of Defense (DoD) official [1] in 2004 to the families of unaccounted-for service members from America’s past conflicts. Twelve years later, this somber reality continues to inspire experts within the US DoD to keep our solemn vow and underwrite for all warfighters the ethos that they “will never leave a fallen comrade.” However, the challenges of keeping that promise are significantly more complex if the fallen hero perished after being contaminated with a chemical, biological, or radiological agent. Despite the myriad of obstacles, dedicated US DoD stakeholders continue to collaborate on developing a strategy, informed by scientific studies, to repatriate contaminated human remains while managing the safety of handlers and transporters and mitigating the risk to public health.
This chapter will provide a brief history of the US DoD’s efforts to establish a capability to repatriate chemically contaminated human remains. It will address current doctrine and gaps and explain current research studies conducted by the US DoD to determine the residual toxic hazards and postmortem risks of chemically contaminated remains. Implications of the study results on operational concepts and procedures will be addressed, and recommendations for future studies will be suggested.
History of Chemically Contaminated Remains
The US military , as well as the international community, has not yet effectuated the daunting task of repatriating chemically contaminated remains from an overseas theater to the continental United States or home country. The historical usage of chemical weapons against US service members in previous wars overwhelmed mortuary affairs capacity and eventuated in the institution of American cemeteries overseas. However, that is no longer considered an acceptable option for bringing closure to the families of America’s fallen warfighters. The expectation within the United States is a commitment to ensuring that our fallen heroes return to American soil with honor and dignity, and this has become firmly ingrained in our national psyche. Since September 11, 2001, “a ‘new normal’ has changed expectations and approaches to caring for the deceased and their families”[2]. As a result, the intent to safely return the remains of service members who have been chemically contaminated to their families is of paramount importance for the US DoD.
The complexities of such an undertaking are immense .To safely conduct the repatriation process, significant regulatory and policy constraints must be adhered to across many jurisdictions. In 2003, the Deputy Secretary of Defense published a policy [3] that required the US DoD to intercontaminate human remains in the theater of operations until a safe means of transporting them back to the continental United States was established. The updated US DoD policy [4], which was published in 2015, now allows for temporary storage or interment of US DoD-affiliated contaminated human remains until the remains can be returned safely through routine mortuary channels.
Current Doctrine and Gaps
While mortuary affairs is a logistics function, safe repatriation of contaminated remains requires integrated activities in the theater of operations between medical, mortuary affairs, chemical, biological, radiological, and nuclear (CBRN) defense, transportation specialists, and the medical examiner. Current logistics doctrine provides for a theater-level mortuary affairs contaminated remains mitigation site (MACRMS) where personnel from various disciplines coalesce to reduce the contamination hazard from exposure to the remains, collect information to provide a scientific identification for the decedent, and place the remains into a package that allows for safe handling during evacuation and transportation to the United States [5]. The integrated MACRMS mission is focused on avoiding second-order contamination effects throughout the repatriation process. Primary functions within the MACRMS include maintaining a chain of custody of the remains, preserving forensic evidence, mitigating the contamination hazard, collecting specimens for positive identification, preparing remains for evaluation, and packaging the remains in a containment system for eventual evacuation to and throughout the United States for final disposition. The medical examiner conducts only a limited postmortem examination at the MACRMS, and there is no embalming on chemically contaminated human remains (C-CHR) at any point. The safety of the MACRMS staff and other personnel who may come in contact with the remains takes priority over the rapid repatriation of the C-CHR.
An enduring capability to repatriate C-CHR requires materiel and nonmateriel solutions. While interim equipment systems have been developed since 2002, the need for approved and fielded equipment systems for the end-to-end capability persists. The MACRMs mission is untested, and procedures have only been developed and validated for a limited number of contaminants. Additionally, service members handling contaminated remains must have appropriate protection during every phase of the repatriation process. Past efforts at identifying equipment requirements determined the need for a contaminated remains recovery pouch, a remains decontamination system to be used at the MACRMS, and a contaminated remains transportation package. Recent efforts have suggested that the requirement for other possible materiel solutions to provide protection during intratheater evacuation to the MACRMS may also exist. Additionally, there is a need for more research on alternatives for low-level chemical contamination detectors, indicators, and decontaminants.
Nonmateriel gaps include shortfalls in current doctrine, which does not adequately address CHR decontamination guidelines when there are multiple contaminants. Moreover, guidelines for decontaminating remains prior to emplacing them into the recovery pouch for hasty burial, temporary storage, or temporary interment need to be further developed. Similarly, doctrinal guidelines to address how to transport CHR from the incident site and/or contaminated casualty collection site to the MACRMS must be developed. Due to the dynamic nature of the CBRN effects on the battlefield and the resultant time lag for standing up an incident-specific MACRMS capability, the US DoD should determine how the decomposition effects due to hasty burial, temporary storage, or temporary interment affect the efficacy of MACRMS operations. Processes for collection and disposition of decontamination waste products at the MACRMS require further development as well.
Other nonmateriel gaps include necessary policies, processes, and procedures to support the return of contaminated remains which have been rendered safe through mitigation and/or containment. Effective protocols are dependent upon the engineering standards of the transportation package that will be developed. In the absence of a CHR transportation package that meets stringent international and federal HAZMAT packaging requirements, the US DoD has been unable to provide specific recommendations to ensure safe and satisfactory final disposition of CHR within the United States. Currently, the US DoD is testing a transportation package which may be an acceptable solution to use for certain C-CHR. Based on the progress made to date in the development of this containment system, the US DoD is able to move forward with coordination between joint, interagency, intergovernmental, and industry stakeholder organizations to develop business practices that can be used as benchmarks during specific instances to transport C-CHR across jurisdictions within the United States and to meet safe and effective standards for final disposition consistent with the laws, policies, and regulations.
The US DoD’s commitment to treating the deceased and their families with the “utmost compassion, respect, professionalism, and dignity throughout the casualty and mortuary, and medical examiner processes” [2] requires that these issues be addressed as expeditiously as possible. Unresolved issues include the need to develop a strategic messaging plan that addresses requirements for nonviewability and direct burial , the need to develop training packets for C-CHR casualty notification and assistance officers and military escorts, and the need to determine if special information briefings for families would be beneficial. The US DoD must determine the requirements for transportation markings and labeling for the C-CHR containment package, develop technical escort protocols for airlift, establish contracts for transportation of the C-CHR within the United States, and determine communication processes to facilitate information exchange throughout the repatriation process. The US DoD should identify potential federal cemeteries that would enter C-CHR and address the possibility of exceptions to eligibility criteria. Other disposition options for families also need to be explored (e.g., interment in private or state cemeteries and cremation). Procedures for burial in a cemetery must be identified. For example, cemeteries may require cement vaults, special markings, and/or periodic monitoring. Finally, the US DoD should determine cremation standards for the C-CHR and the containment package, identify approved cremation facilities, and coordinate contracts to ensure compliance with the existing US DoD standards for cremation.
To develop effective protocols , the US DoD needs to also explore opportunities to resolve gaps in science and technology. The lack of clearance levels specifically for contaminated human remains necessitates the containment of the hazard in a safe package. Until a determination can be made that exposed remains can be considered decontaminated to a safe level, commanders will need to know when and how to categorize chemically exposed remains as C-CHR. In addition to further studies to determine the distribution and persistency of the hazards associated with different agents, there is a need for investigating the effects of certain decontaminants on the distribution and persistence of hazards from different agents on and within the remains to determine both the short-term risks to handlers and transporters and the long-term risks to public health. Development of additional decontaminants that reduce water requirements and waste would be beneficial. Research efforts to determine if there is a point at which decontamination operations should not be done or if large volumes of decontaminants (spray or submersion) can be used to reduce processing time for CHR should be done in the future. Processes for dealing with contaminated personal effects disposition and regulated medical waste must also be informed by scientific studies.
Current Research
Background
To date, little research has been done to support the decontamination or safe handling of C-CHR. Instead, research efforts have mainly focused on the protection against exposure to chemical warfare agents (CWAs) and therapy to increase the survivability of victims after a CWA exposure . However, after a severe intoxication, chances are profound that victims will not survive, despite aggressive treatment. During the handling of CHR and personal effects, the agent may still be present on the skin, in bodily fluids or tissues, or on/in personal effects and may pose a contact and inhalation hazard to unprotected personnel. Agents may be present for a longer period of time in human remains compared to living human beings due to the postmortem changes of physiological processes that influence the biological and chemical fate of the agents.
The presence of toxic agents on or inside the body of deceased victims, as well as on their clothes, poses a threat to (unprotected) personnel handling the remains. Several (civil) cases are known from history, in which handling contaminated victims leads to intoxication of rescuers. For example, in 1943, German bombers attacked ships in the harbor of Bari, including one which was carrying sulfur mustard. Rescuers were unaware that they were dealing with sulfur mustard casualties, and many additional victims were caused among the rescuers by contact with the contaminated skin and clothing of victims.
Additionally, secondary exposure of ambulance personnel and medical personnel also took place after the terrorist attack in the Tokyo subway with sarin gas in 1995. Secondary exposure took place because victims were not decontaminated and their outer clothing was not removed before transportation to hospitals, personnel did not wear adequate protection, and ambulances were not ventilated. Thus, 135 ambulance workers [6] and 110 members of the medical staff [7] became intoxicated. It has been assumed that the secondary exposure resulted from off-gassing of sarin from the clothing of victims [6, 8]. No information was found on the off-gassing from the bodies of (deceased) victims.
The 1994 sarin attack in Matsumoto also led to the contamination of rescuers, but this was probably due to direct contamination on-site, rather than secondary effects. The severity of intoxication was directly related to the time after the incident at which the rescuers arrived [9].
It has been estimated that 80% of the contamination will be present on the clothing of victims after a chemical incident. Contaminated clothing and/or outer gear should be removed from the body as soon as possible to reduce the risk of secondary contamination. These contaminated items will present both a contact and inhalation hazard . Especially porous materials, such as rubber, are known to absorb CWAs, leading to a prolonged hazard. Obviously, the hazard of contaminated clothing is also relevant in the case of surviving victims.
The secondary hazard from decontaminated human remains may seem less important than the hazard from contaminated clothing. However, after removal of clothing and decontamination of skin and hair, the hazard may not be completely removed as deceased victims may continue to emit fluids or gases after decontamination. A vapor concentration may build up when a body has been temporarily stored in a refrigerated body bag or coffin at a morgue or temporary site. After opening the coffin at room temperature, e.g., for autopsy examination, the vapor may be released and pose an unexpected hazard.
An essential tool for the determination of the actual hazard of CHR and personal effects is the use of effective chemical agent monitors. This handheld detection equipment responds to the presence of vaporized agents and is required for ongoing detection, identification, and monitoring of human remains to detect the presence of hazards [10]. It is vital that the current detection equipment be able to detect low-level concentrations of vapor from all CWAs.
The expected hazard will depend on the type of CWA. For sulfur mustard, the contact and evaporation hazards are equally important. VX is known to be a slowly evaporating CWA. It was recently confirmed that the agent poses a greater contact hazard than an evaporation hazard [11]. On the other hand, sarin is known to evaporate rapidly. The agent poses an inhalation hazard, but only for a short period of time since the agent is rapidly fully evaporated. It is anticipated that the hazard of sarin will be more significant on contaminated clothing materials than on human remains.
Biological Fate of CWAs in Healthy Humans
The distribution and metabolism of CWAs in living organisms have been studied extensively. After exposure, agents will be absorbed, distributed, metabolized, and excreted, depending on the route of administration. Some useful data were obtained from experiments on human volunteers in the 1940s and 1950s [12–14], as well as from extensive toxicokinetic studies on laboratory animals [15–17].
The biological fate of nerve agents is relatively simple [18–21]. The predominant process consists of hydrolysis (either spontaneous or enzymatic) to relatively nontoxic phosphonic acids that are readily excreted in urine. In addition to binding to its physiological target acetylcholinesterase, scavenging by butyrylcholinesterase (BuChE) , carboxylesterase (CaE) , and even albumin has been well documented [22]. The metabolism of sulfur mustard is complex, among other things, because of the agent’s bifunctional alkylating character, resulting in a wide range of mixed hydrolysis/oxidation products and glutathione-derived conjugates in various oxidation stages, DNA adducts, and cancer. Also, an extensive binding to proteins occurs [18–20, 23].
Enzymatic activities and hydrolysis rates of CWAs in plasma and tissue homogenates have been well documented. These data were used to develop a physiologically based pharmacokinetic (PBPK) model to predict the toxicokinetics of nerve agents in intoxicated (living) human beings [17, 24].
Postmortem Biological Fate of CWAs
After death, physiological processes start to change rapidly, many of which will have an effect on the biological and chemical fate of CWAs. When a victim dies slowly, some changes may start even before death (such as a reduced blood circulation and a change in percutaneous uptake). It is anticipated that CWAs will remain present in their parent form for a longer period of time in human remains compared to healthy human beings, because of the slowed or terminated processes of natural detoxification. On the other hand, certain biochemical mechanisms may be activated following death which may enhance the destruction of CWAs.
The transportation of agent through the body by the blood circulation stops immediately after death. As a result, metabolism of the agent by the liver ceases.
The body temperature gradually cools from 37 °C to ambient temperature (algor mortis).
Gradual muscular stiffening (rigor mortis) will occur approximately 6 hours after death and is caused by a physicochemical change in muscle protein.
Postmortem decomposition of the soft tissues (putrefaction) by enzymes and bacteria starts between 36 and 72 hours after death, depending on external factors such as outside temperature, location of body (e.g., in the water), etc. Putrefaction starts in the anterior abdominal wall and results in the gradual dissolution of all tissues into gases, liquids, and salts.
Saponification is the hydrolysis of fatty tissues with the release of free fatty acids. This process starts within weeks after death at room temperature.
Postmortem redistribution of the agent may occur throughout the body. Immediately after death, blood circulation is terminated. Still, agent concentrations in body fluids and organs may change, similar to drugs, due to postmortem redistribution [25]. Agents may be redistributed from “reservoir” organs such as the gastrointestinal tract, liver, and lungs to surrounding tissues. This may occur immediately after death by diffusion through blood vessels and transparietal diffusion toward the surrounding organs.
Postmortem scavenging by enzymes and proteins may still continue to occur, although to a limited extent. Natural detoxification of nerve agents occurs by binding to scavenging enzymes. The total amount of available enzyme (BuChE and CaE) is normally limited to about 60 nM in human blood. Victims that succumbed to a lethal dose of nerve agent will have enzyme activity levels that approach zero and detoxification by scavenging to these enzymes is no longer possible. Some enzyme activity may still be present, if there has been an alternate cause of death (e.g., the blast of an explosion) in addition to a nerve agent intoxication. Although enzyme activity will decrease in time due to the decrease in temperature, it has been shown that cholinesterase activity levels in the postmortem blood of nonintoxicated patients were almost identical to those in serum samples from healthy controls [26]. However, in the case of nerve agent exposure, it is estimated that postmortem scavenging will play a limited role in detoxification when it is assumed that the received dosage will be far higher than the amount of available binding sites. Nonetheless, binding to sites with less affinity (e.g., the tyrosine-411 residue in albumin) might occur under these conditions. In the case of sulfur mustard, alkylation of proteins (e.g., hemoglobin and albumin) and DNA will contribute to the postmortem detoxification of this agent.
Postmortem metabolism of CWA is expected to occur, but at a much slower rate, due to the decrease in body temperature and the cessation of liver metabolism. It has been shown that the decomposition of organophosphate pesticides continues postmortem [27]. Nerve agents will be detoxified by spontaneous and enzymatic hydrolysis, whereas sulfur mustard will undergo hydrolysis and oxidation. In addition, alternative, yet unknown degradation pathways may arise, e.g., by bacteria during putrefaction. In general, metabolism leads to agent detoxification, but it cannot be excluded that under postmortem conditions, metabolism may be incomplete or slightly altered and consequently might give rise to the formation of toxic reaction products, such as desethyl-VX (EA2192) in the case of VX and mustard sulfone in the case of sulfur mustard. Many factors play a role during postmortem agent degradation. The process is complex and is expected to be slow, especially for the more persistent agents. This was shown, for example, by the reported presence of unmetabolized sulfur mustard in postmortem tissue samples from Iranian victims [28, 29].
Current Research
There have only been two major studies performed in recent years, both funded by the Defense Threat Reduction Agency (DTRA), which investigated the hazard remaining on chemically contaminated remains. Both studies were designed as first steps to fill the knowledge gap surrounding this topic and provide information into the hazard to personnel handling chemically contaminated remains.
Guinea Pig Contaminated Remains Hazard (VX, Sulfur Mustard)
In the first study, performed by TNO in the Netherlands, the biological and chemical fate of a number of CWAs [VX and sulfur mustard (HD)] was determined in euthanized and CWA-contaminated hairless guinea pigs. Both the residual contact and inhalation hazards were determined through 96 hours following contamination and euthanasia (30 min after contamination). Animals were contaminated with eight 1-μL drops of liquid VX (>100 percutaneous LD50) or HD (<1 percutaneous LD50). Additionally, animals were exposed to a whole-body vapor exposure of HD, and the residual vapor and contact hazard were evaluated.
In VX-contaminated hairless guinea pigs, it was determined that the amount of VX on the skin decreased gradually but was still present after 96 hours at levels between 20 and 90 μg/cm2. VX levels in the blood were also determined through 22 hours, with levels remaining fairly constant (low ng/ml range) over time. VX was determined to be present at much higher levels in the liver (up to 7 μg/g liver) than in the blood, especially after 5 hours, which might be an indication of agent redistribution. The metabolism of VX into its hydrolysis product, EMPA, could only be analyzed in liver samples at variable levels (2–200 ng/mL), which was in agreement with the high and variable VX concentrations found in the liver. The toxic metabolite of VX (desethyl VX; EA2192; V27A) was only found in one of the blood and liver samples, and it was at extremely low levels (0.2 ng/mL).
In HD-contaminated hairless guinea pigs, HD on the skin was found to not be very persistent after death, when at ambient room temperature. Approximately 3 hours after application (2.5 hours after death), HD could no longer be detected on the skin using tape stripping. In the blood, intact HD could be detected through the last blood sampling time point (23 hours post death), with levels gradually decreasing from 20 to 3 ng/ml. In the liver, HD was detected for up to 48 hours post-death (up to 25 ng/g liver) following contamination, with gradually decreasing levels. Sulfur mustard in the liver was detected at much lower levels than VX in the liver, probably reflecting the much higher intrinsic reactivity of sulfur mustard compared to VX. The vapor hazard from these remains was most pronounced in the first 24 hours after death, with amounts of off-gassed HD up to 500 μg/h. However, when liquid HD was applied to hairless guinea pigs at low temperatures (5–7 °C), agent levels in the blood and liver were significantly higher than those found at ambient temperatures. This might be caused by a lower reactivity of the agent at lower temperatures, and/or because more agent had penetrated the skin. The latter explanation is in agreement with the decreased off-gassing observed during the initial (0.5–1 hours) postexposure time period, immediately following contamination. Also, it seems that cooling of the remains prolongs the process of off-gassing.
The relatively nontoxic sulfur mustard metabolite , sulfur mustard sulfoxide, was found in the blood of the remains of hairless guinea pigs, after percutaneous contamination with sulfur mustard. In addition, protein adduct formation was determined by mass spectrometric analysis of a cysteine sulfur mustard adduct, after pronase digestion of whole blood. Similar adduct formation has been observed under normal in vivo conditions. From a practical point of view, it is worthwhile to note that the detection equipment appears to respond at later time points (> 72 hours post death), probably because of natural putrefaction products which are formed after death.
Hairless guinea pigs that were exposed to whole-body HD vapor (applied dose 10,000 mg.min.m−3, 250 mg.m−3 during 40 min) had, as expected, much lower levels (up to 0.04 μg/cm2) of HD on the skin compared to those found following a liquid exposure. The vapor hazard levels were also found to be lower (up to 7 μg/h off-gassed HD) than that compared to a liquid exposure. However, the internal levels of free HD (as measured in blood and liver) were of the same order of magnitude as found following a percutaneous liquid exposure.
Swine Contaminated Remains Hazard (VX)
In a study performed by Battelle (Columbus, OH, USA), the contact and inhalation hazard remaining on VX-contaminated Yorkshire swine was determined through 1 week post-death (unpublished data). To mimic a more realistic situation, the remains were stored at room temperature following death for approximately 24 hours prior to decontamination. Cold storage conditions (1.1° to 4.4 °C) were used after 24 hours post-death to mimic the procedures and storage conditions likely to be followed by the US Mortuary Affairs in the event C-CHR would need to be processed. Half of the animals were nondecontaminated controls, and half of the animals were decontaminated in accordance with the US MACRMS Protocol, to determine the effectiveness of the current US MACRMS Protocol against a gross VX contamination.
The contact and inhalation hazard remaining on female weanling Yorkshire swine due to a gross VX contamination was determined through 1 week post-death. In addition, the rinsate used as part of the decontamination process was collected and sampled for parent compound and EA2192, a toxic metabolite of VX, to determine the hazard that would be present in the run-off fluids during the decontamination process.
Deeply anesthetized animals were exposed to approximately 9.5 mL neat VX (purity of 96.3%, provided by Edgewood Chemical Biological Center) percutaneously on the ventral abdomen. Although the application of 9.5 mL of VX (approximately 9.5 grams) on a swine for the purposes of determining the contamination hazard of remains may seem extreme, the purpose of this study was to mimic a worst-case scenario that would be found on a battlefield as closely as possible in order to provide relevant information that would inform the tactics, techniques, and procedures (TTPs) on safe handling and decontamination of chemically contaminated remains. In 2004, 155-mm artillery shells were found in Iraq that contained 3–4 L of sarin. A service member that was near “ground zero” during an explosion of one of these shells would easily be expected to be exposed to the quantities used on this study (9.5 mL), and possibly more. Additionally, in a technical report produced by the US Army, it was estimated that a worst-case scenario for contamination of remains would be 200 grams per man following exposure to a “puddle” of agent, and contamination due to a tactical ballistic missile attack with VX would be approximately 2–6 grams per man (Papirmeisteret al., 1993). As a result, the 9.5 grams of VX used in this study provided a reasonable potential exposure for a service member near the site of the attack and potentially a worst-case scenario for decontamination.
Due to the large volume of neat agent that was used , the surface area of the swine abdomen was not large enough to prevent run-off of excess agent. As a result, an unknown amount of agent rolled off the side of the animals, resulting in an overall contamination of less than 9.5 mL of neat VX. Animals remained anesthetized through death. Following death, the remains were kept at room temperature for 24 hours and were either transferred to containment boxes without decontamination or were decontaminated and then transferred to containment boxes for storage at 1.1° to 4.4 °C.
The remains were washed with warm, soapy water using a soft sponge.
Remains were then rinsed with 750 mL of room temperature tap water. A sample of this rinsate was collected and analyzed for the contact hazard of VX and EA2192 that would remain.
Following the soapy water scrub and rinse, the remains were placed in a 5% sodium hypochlorite solution (pH >11; temperature between 20 and 25 °C) for 60 minutes. (Note: It is important for VX to be decontaminated with a pH less than 7 or greater than 10. Between pH 7-10, toxic metabolites of VX are likely to form.)
After a 60-minute soak in the hypochlorite solution, the remains were transferred to a room temperature rinse water bath for 5 minutes.
Following decontamination, remains were then placed in cold storage as detailed above.
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