Chemical Decontamination

Equipment

Personal protective equipment (PPE) functions as a barrier between the responder and the environment or an exposed victim. PPEs are classified into levels A, B, C, and D depending upon the level of protection offered. Each classification designates a level of protection for the respiratory system, body, eyes, face, hands, and feet. The highest degree of protection is level A protection, but healthcare facilities generally do not have PPE capability higher than level C.

Level A protection is used in situations where there is a high potential for exposure to harmful vapors or particles, areas of poor ventilation with limited or no breathable atmosphere, or areas with a high potential for skin contact with a known hazardous substance. The hallmark of level A protection is that it is completely self-contained and therefore is vapor impermeable. PPE for level A exposure includes:

• Full-facepiece self-contained breathing apparatus, or positive pressure supplied area with a secondary self-contained breathing apparatus.
• Encapsulating protective suit
• Chemical resistant outer and inner gloves
• Chemical resistant steel-toed boots
• Disposable complete outer suit, worn over the encapsulating suit 

Level B protection, like level A, is a capability that is generally used by highly-trained HAZMAT personnel and is not typically available for use at healthcare facilities. It does share the capability of having a self-contained breathing apparatus, but unlike level A, it is not vapor-impervious. This level of protection is utilized in situations of low oxygen concentration or when vapors are present that are not thought to pose a high risk of skin absorption, such as organophosphate insecticide or military-grade weapon. The components of this level of protection include:

• Full-facepiece self-contained breathing apparatus, or positive pressure supplied area with a secondary self-contained breathing apparatus
• Hooded chemical resistance clothing with a face shield
• Chemical resistant outer and inner gloves
• Chemical resistant steel-toes boots with an outer disposable covering

Level C protection, as noted previously, is the highest level of PPE utilized by most healthcare facilities. Level C is utilized in a situation when there is a high possibility of dangerous air contaminants or if there is a possibility of hazardous liquid splashes. The primary difference between level B and level C protection is the absence of a self-contained breathing apparatus. It is important that receiving stations, such as emergency departments, have the needed components of this level of protection pre-stock and prepared for rapid deployment in the event of a short or immediate-notice patient who is contaminated with a potentially hazardous chemical. PPE for level C protection includes:

• Air-purifying respirator that is either full-face or half-mask
• Hooded chemical-resistant clothing with face-shield.
• Chemical resistant outer and inner gloves
• Steel-toed boots with an outer disposable cover

Level D is the lowest degree of protection and should be utilized when the atmosphere contains no known airborne contaminant. There is no risk for inhalation or contact absorption of a hazardous chemical. While offering little in the way of hazardous chemical protection, this is the most likely PPE level utilized when a victim is received at a healthcare facility. Therefore, a plan must be in place to enable treating personnel to don additional protective equipment rapidly. Level D components include the following:

• Face shield
• Chemical splash goggles or safety glasses
• Gloves
• Boots or shoes
• Work uniform

Clinical Significance

In an ideal situation, EMS will have taken steps to decontaminate casualties before medical treatment center arrival. Expert consensus indicates that, when feasible, chemical decontamination should take place within one minute of exposure.[2] Some exposures will incapacitate victims or produce severe symptoms.  In those cases, EMS is likely to be called.  However, there will be patients transporting themselves directly to the medical treatment facility. The healthcare provider’s initial impulse may be to move the patient to a treatment area and initiate care; however, this could potentially put the provider and facility at risk for contamination and incapacitation. For example, following the Aum Shinrikyo Tokyo subway attack in 1995, many pre-hospital and medical facility personnel experienced a secondary exposure to the military-grade organophosphate sarin.[3] A practical but step-wise approach to decontamination will protect the patient, the providers, and the treatment space.

Step One: Donning Personal Protective Equipment (PPE)

Step Two: Remove Victim Clothing As Soon As Possible

Clothing serves as a reservoir for chemical contaminants, especially liquid-based chemicals. Any attempt to decontaminate a clothed patient could result in the transfer of additional before onto the skin surface, or in the event of an injured patient, further introduction of chemicals into deep tissues. The initial step in the treatment process is to remove the patient’s clothing as soon as possible. Previous guidance indicated that the removal of clothing would reduce 80 to 90% of chemical contamination.[4] Unpublished mannequin studies indicate that clothing removal reduces contamination by 50 to 70%.  This action is essential with liquids where the efficacy of decontamination decreases rapidly over time, so expeditious removal is an essential first step.[5] Removal of clothing outside of the treatment area will help to prevent facility contamination. It is reasonable and important to respect patient privacy and utilize disposable attire, bedsheets, or gowns following the removal of clothing and decontamination. If possible, store all removed clothing and adornments in an impermeable container such as a well-marked plastic bag to prevent further dissemination of the offending chemical.

Step Three: Remove/Inactive the Contaminant

Once the patient has been disrobed, removed any solid or particulate material before initiating irrigation. Some dry chemicals can be exothermic and can cause additional harm to the patient when exposed to water. Remove these particles using a soft brush or cloth, or if available, a battery-powered hand-held vacuum. After removal of all clothing and particulate matter, then provide dry or aqueous decontamination. Dry decontamination products are generally only available in specific occupational, military, or HAZMAT unit locations.  They can be used before irrigation, although this will not be practical or available at most healthcare facilities. Dry decontamination can be performed using an absorptive material such as Fuller’s earth, activated charcoal, talcum powder, or absorptive materials such as paper towels or diapers to reduce dermal exposure before irrigation. The addition of a dry decontamination step may be more effective than aqueous irrigation alone. However, all used absorptive materials should be considered as hazardous waste, and a plan must, therefore, be in place to dispose of these expended materials.  

Irrigation with water is essential to reduce contamination and toxicity, but some liquid soluble chemicals, especially organophosphates and similar insecticides, are not readily removed with water alone. The addition of detergent (mild soap) will result in enhanced removal of lipid-soluble chemicals, such as organophosphates, and will result in decreased toxicity and improved survival.[6] Paradoxically, prolonged exposure to water can enhance the systemic absorption of some chemicals, known as the “wash-in effect.”[7] Research from the European Union’s Optimisation [sic] through Research of Chemical Incident Decontamination Systems (ORCHIDS) reveals that the optimal washing time is 90 seconds, and the additional use of a soft cloth to clean all skin surfaces thoroughly can further improve decontamination rates by additional 20%[5]. Care must be taken not to cause abrasion or otherwise disrupt epidermal surfaces to prevent the introduction of the contaminant into the dermis.

If open wounds are present, the areas should be thoroughly irrigated as well. Using a physiologic solution such as Lactated ringers or normal saline will help prevent pain and further tissue injury.

Many sources discuss the use of dilute bleach solutions to enhance decontamination. However, even a diluted 0.5% solution could potentially cause eye and wound irritation. The use of a one percent soap-water solution is nearly as effective as diluted sodium hypochlorite solutions for removing military-grade organophosphates.[8] Unlike diluted bleach, soapy water and will not cause internal injury if inadvertently introduced into wounds. If water is in short supply, a dilute bleach solution can be applied but should be rinsed off several minutes after application.

If available and under the right circumstances, reactive skin decontamination lotion (RSDL) is an option as an adjunct to aqueous decontamination. RSDL consists of multiple components, including Dekon 139 and 2,3-butanedione monoxime (DAM), which chelate and inactive several military-grade chemical agents. RSDL has been formulated to remove and neutralize several agents, including organophosphates, vesicants such as mustard gas, and can be used to decontaminate T-2, a weaponized fungal toxin. It comes packaged with a pre-treated sponge. One sponge is not sufficient to completely decontaminate an individual and is intended for use on the face, neck, hands, and the inner surface of a respirator. RSDL is more effective than diluted sodium hypochlorite and soapy water alone.[8]

Other options for chemical decontamination exist but do not have current approval for use in the United States. Amphoteric chelating solutions are currently available for use in some countries and have demonstrated effectiveness for both chemical decontamination as well as attenuating tissue injury from hazardous agent exposure. One review of one amphoteric chelating irrigation fluid suggested improved outcomes from chemical burns to the skin and eyes.[9]

Enhancing Healthcare Team Outcomes

Providing care for injured patients from hazardous chemical exposure is an uncommon scenario but can be very disruptive to normal clinical operations. The entire interprofessional team of acute care providers needs to be familiar with the principles of decontamination. Institutional protocols and scheduled practical exercises are helpful to ensure readiness to care for individuals exposed to hazardous chemicals. Pre-positioned supplies should be readily available in patient receiving areas of the healthcare facility, and additional stocks of supplies should remain on hand in the facility for replenishment.