Chemical Decontamination

Decontamination is defined as the reduction or removal of chemical (or biological) agents by physical means or by chemical neutralization (detoxification) so that agents are no longer hazardous. The major objectives of decontamination of victims exposed to a hazardous chemical is the prevention of further harm from the substance and the optimization of the chance for full clinical recovery. An important secondary objective is to avoid spreading contaminated material to others or the health care facility (HCF). Although accidents from the manufacture, storage, or transportation of chemicals account for most instances of patient contamination, HCFs must now anticipate the intentional use of chemicals (including chemical warfare agents) to contaminate potentially large numbers of victims who may enter the facility individually or en masse, with or without prior decontamination. This chapter focuses on the decontamination of patients exposed to chemical warfare agents before entry to an HCF and the issues associated with preventing secondary or cross contamination of health care providers and their facilities. Also discussed are the problems associated with treating contaminated patients while wearing personal protective equipment (PPE).

Chemical agents exist in liquid, solid, or vapor form. Inhalation of vapors is the most likely route of exposure. Depending on the chemical’s characteristics, physical properties, and exposure pathway, treatment for chemical warfare agent–contaminated patients is similar to other chemical casualties in the HCF environment. The management of terrorist-related events is more complex. A chemical attack would likely occur without warning, with an unknown substance, and in a location where large numbers of people are present or likely to pass through. These “outrage” factors elevate the perception of risk and safety-related fears, resulting in heightened psychological harm. Other factors—a sense of helplessness and fear of unknown consequences from the exposure to oneself and others—may also result in large numbers of the “walking wounded” converging on an HCF without prior decontamination.

Given the covert measures usually employed by terrorists, health care providers should routinely be alert for signs and symptoms of contamination on patients and take immediate steps to protect themselves and their facility from becoming secondary victims. Facility managers, especially emergency department directors, should communicate early with first responders about unusual incidents to ensure prompt notification about any potentially contaminated patients. The same personnel should have the authority to lock down the HCF and reroute response teams and self-presenting victims to appropriate decontamination areas.

Field decontamination is generally the task of first responders (e.g., firefighters and hazardous materials [HazMat] teams) trained to use PPE and to process victims through decontamination units at the site of the chemical release. After an accidental release, the chemical’s characteristics (including toxicity, persistence, and health effects) are frequently known through information on material safety data sheets or from managers or employees at the release site. Conversely, in a terrorist event, the chemical substance will likely be unknown, the dose uncertain, and the subsequent health effects undetermined. If the victims include children and infants, input from pediatricians and poison specialists will be needed. All victims will require debriefing (even if the chemical agents remain unknown at the time) after decontamination and treatment.

Field decontamination procedures are carried out in both rural and urban settings by full-time first responders or part-time volunteers with or without special equipment or training. Field decontamination of the potentially exposed often occurs as a precautionary measure, especially when health effects are unclear. Working with the hypothesis that removal of clothing reduces the majority of contaminants, most field decontamination efforts involve clothing removal and showering, either in a special decontamination unit (e.g., trailer on expedient setup) or by hosing off from firefighting hoses. The objective of field decontamination is to transfer a clean victim to an HCF without contaminating the conveying vehicle or exposing others. Given the large uncertainty of field decontamination effectiveness, most victims undergo another round of decontamination at the HCF to ensure the level of cleanliness needed to protect the facility. Patients are often frightened during this process and may question the need for a second round of decontamination. First-receiving facilities should include an aggressive information operation campaign in all of their chemical attack response activities. It is essential that the HCF be able to lock down as soon as the potential for arrival of contaminated victims is detected, to protect critical assets such as health care providers, the HCF, and the existing patient population.

The most important element of treatment after exposure to a chemical warfare agent is to immediately remove the agent through decontamination. Decontamination that is delayed or ineffective can escalate the number of casualties when very toxic substances, such as nerve agents, are involved. If injuries are life threatening, victims are sometimes transported with minimal attention to the decontamination unit before arrival at the HCF. This problem can be exacerbated if communications between the field response units and medical facility fail to describe the event so that the HCF can take advance precautions, such as suiting up personnel in PPE, performing lockdown, and initiating decontamination setup. In a terrorist event, the number of victims transporting themselves to emergency departments could quickly overwhelm resources, as happened in the Tokyo subway incident.

Treating a chemical warfare agent–contaminated patient is similar to handling patients contaminated by other hazardous chemicals, such as organophosphate pesticides, and requires similar precautions. Over 95% of surface contaminants can be eliminated by removing clothing and showering. Although the process is well known and easy to accomplish with ambulatory victims, injured patients require increased numbers of personnel and resources to perform decontamination.

The three primary types of decontamination important to the health care provider are as follows:

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Personal decontamination (i.e., self-decontamination or buddy decontamination when one is exposed)
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Casualty decontamination (i.e., decontamination of casualties)
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Personnel decontamination (generally, decontamination of noncasualties)

Personal decontamination may or may not involve PPE. More often, personal decontamination (i.e., disrobing and bagging clothing, then showering with copious amounts of soap and water) is needed after an unprotected health care provider is exposed while caring for a contaminated patient who presents to an emergency department without alerting the admitting staff. If PPE is worn, all equipment including outer garments, gloves, boots, and respiratory apparatus should be decontaminated after removal. This will avoid the unnecessary cost of replacing expensive and individually fitted PPE. Health care providers should also be instructed in the proper donning and doffing of PPE to prevent exposing themselves or others to contaminated clothing surfaces.

Decontamination of chemical casualties and other exposed personnel requires a substantial outlay of resources and personnel. Not all decontamination efforts will involve health care providers directly because HazMat teams are the general providers. However, medically trained personnel should provide overall supervision. The decontamination of each person should be monitored for adequate removal of agents and not left to the subjective evaluation of victims, especially children. This process requires sensitivity and tact when handling civilian casualties, especially in the stressed environment of the disaster aftermath.

Decontamination solutions

Many substances have been evaluated for their ability to remove contaminants from the skin. Compared with washing the skin with copious amounts of soap and water and irrigating the eyes with clean water, most have been found lacking. The most common problems are skin irritation, toxicity, ineffectiveness, and high cost. Although the military has used substances (such as special wipes) to determine whether the contaminant is removed, most health care providers must rely on subjective evaluations to assess decontamination effectiveness.

Disposal of contaminated solutions from decontamination of victims should follow the same procedures as disposal of other hazardous materials. If the contaminant is unknown or is suspected as benign at the time of decontamination, precautions such as holding secured drums of solution until a definitive result is obtained from later laboratory analysis can save the considerable expense of sending the wastewater to an HazMat disposal site. The U.S. Environmental Protection Agency (EPA) notes that in special circumstances where the protection of populations is critical, contaminated water can be diverted to storm sewer or sanitary disposal. Although this is likely not an option for persistent biological agents, most chemical agents would likely be dispersed in this way without causing further harm.

It is often assumed that trained HazMat personnel perform normal decontamination procedures outside the emergency department; however, during an emergency, those same providers will likely be involved in search and rescue activities, with decontamination of exposed victims a low priority. Many victims will likely self-evacuate to the nearest medical facility without advising emergency department personnel. After the Tokyo subway release of sarin, it was estimated that more than 10,000 victims presented to medical facilities on their own without any form of decontamination before arrival.

Secondary contamination

Because of the potential for secondary contamination, it is essential that medical personnel understand the need for and undergo training in the actual use of PPE. Surgical masks are not sufficient to protect against hazardous vapors from a contaminated patient’s fluids or body parts. This is also a problem if the contaminant was purposely ingested and regurgitated in vomitus. Some persistent chemical warfare agents are not immediately symptomatic or visually evident on a patient’s skin, hair, or clothing. For example, sulfur mustard is a persistent oily substance producing signs and symptoms that can be delayed for 2 to 24 hours after exposure. It is also important that deceased victims of chemical agent events (even in body bags) be decontaminated prior to release to prevent secondary contamination of unsuspecting forensic or funerary workers.

A serious issue regarding chemical agents is the general absence of criteria to determine the effectiveness of decontamination efforts. Field decontamination performed by HazMat personnel is generally considered gross decontamination and should not be considered adequate for admitting patients to a medical facility. This is a serious problem if the medical facility has not planned for decontamination of patients being admitted and health care providers respond without determining the cleanliness of patients. Reports of emergency departments being closed for several hours after health care providers were sickened by fumes from patients who were only field decontaminated suggest this could be a very real problem in large-scale disasters. Not only would the loss of health care providers create difficulties but also certifying that the HCF was clean enough to reopen could take several hours or, in the worst cases, several days. In a major disaster that disrupts normal infrastructure channels and communications, medical facility deliveries could be delayed for several days.

Chemical agents that might be used in a terror event include a wide variety of substances, ranging from chemical warfare agents such as nerve and sulfur mustard agents to riot control and choking agents. (Some consider toxins such as ricin from the castor bean plant a chemical derivative, but most authorities characterize toxins as biological agents because they are derived from living matter.) The individual chemical’s characteristics and mode of release and the victim’s own characteristics will determine how decontamination is performed. For example, most victims exposed but not symptomatic can accomplish decontamination on their own. But patients who are injured, wheelchair bound, elderly, or very young will require assistance. Decontaminating victims on litters often requires a team effort to coordinate the lifting required to move the victim from the dirty (hot) to clean (cold) zones.

An issue with most health care providers, especially in emergency departments, is the lack of training on wearing PPE while treating victims. PPE is becoming more available in emergency departments because The Joint Commission requires an emergency response incident management system that is integrated with the community response system. However, periodic training in the actual use of equipment during patient treatment is still lacking. Having enough equipment for each person and providing the necessary training (8 hours for some PPE) are often restricted by budgets and the common misperception that a mass chemical casualty event will not occur in one’s hometown. As respirators must be fitted for individual use to prevent leakage around the face to protect the mouth and eyes, use of individual pieces of respiratory equipment by multiple persons is not acceptable. Each wearer must also be trained in the proper decontamination of the PPE and how to don and doff the equipment effectively. Otherwise the facility, victims, and other health care providers will be placed at risk of secondary contamination.

Communication with patients and with other health care providers is difficult when wearing a full face mask respirator. Handling equipment and providing care are severely hampered when wearing the recommended 7-mm-thick gloves instead of the more common latex ones. Movements are often hindered by cumbersome outerwear, especially if the facility uses a common air line for the supplied air for respirators. Those who do not want to wear PPE and instead rely on common barrier practices should not be allowed into the arena because the threat of secondary contamination from victims is too serious to allow the practice. Appropriate training in PPE can alleviate the feelings of confinement and dread that often affect first-time users. Enacting policies and publicizing them within the facility will help eliminate problems with noncompliant personnel during an actual event.

The Occupational Safety and Health Administration (OSHA) mandates specific stay and rest times while wearing PPE, especially in hot or cold environments. This adds to the total number of health care providers needed during the event. PPE and wear-time requirements dictated by state health authorities or OSHA may be more stringent than federal regulations and should be addressed in training sessions. Jurisdictional disputes over appropriate PPE and the training required should be addressed in reviewing yearly plans and in all Memorandums of Understanding (MOUs) and Memorandums of Agreement (MOAs) with other facility managers.

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