Chemical Decontamination


Article Author:
Gregory Johnston


Article Editor:
Brandon Wills


Editors In Chief:
Marlon Bayot
John Sanchez
Bruce Blanchard


Managing Editors:
Avais Raja
Orawan Chaigasame
Carrie Smith
Abdul Waheed
Khalid Alsayouri
Frank Smeeks
Kristina Soman-Faulkner
Radia Jamil
Patrick Le
Sobhan Daneshfar
Anoosh Zafar Gondal
Saad Nazir
William Gossman
Pritesh Sheth
Hassam Zulfiqar
Navid Mahabadi
Steve Bhimji
John Shell
Matthew Varacallo
Heba Mahdy
Ahmad Malik
Mark Pellegrini
James Hughes
Beata Beatty
Nazia Sadiq
Hajira Basit
Phillip Hynes
Tehmina Warsi


Updated:
2/12/2019 11:54:20 AM

Introduction

Contending with a mass casualty incident involving a chemical exposure seems daunting; fortunately, these are rare events.  It is quite possible that acute care clinicians will encounter single patients or possibly several individuals presenting for care following hazardous chemical exposure. Emergency medical services (EMS) have protocols and employ providers who are well versed to respond to hazardous chemical exposures, but these specialized response teams take time to mobilize.  It is likely that injured patients, including those exposed to a dangerous chemical, will arrive at a healthcare facility before undergoing decontamination.

Chemical exposure and subsequent tissue injury or organ-system dysfunction are both dose and time-dependent.  Some hazardous materials will produce toxicity even after removing an individual from the “hot zone” or source of exposure. Chemical exposures, in general, will cause injury more rapidly than radiological or biological agents. Given the relationship between exposure time and degree of injury, immediate decontamination is essential to limit further absorption as well as reduce potential hazardous exposures to treating healthcare providers.[1] In the case of noxious or highly toxic substances, contamination can render a healthcare treatment site inoperable; thus initiation of decontamination outside of the patient treatment area is essential. Decontamination is best initiated prior to arrival to the medical treatment facility, but this not always feasible. This review will focus on decontamination at the site of a medical treatment facility. Most medical treatment facilities do not possess extensive equipment and expertise compared to highly trained hazardous materials emergency medical services (HAZMAT) teams, however, review of personal protective equipment (PPE) options, even if unavailable to the provider, is relevant.

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 known as 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 if poor ventilation with limited or no breathable atmosphere, or in areas where there is a high potential for skin contact with a known hazardous substance. The hallmark of level A protection is that 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 and 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. A plan must, therefore, be in place to enable treating personnel to rapidly don additional protective equipment. 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] Employing a practical, but a 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 chemical. 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 result in a reduction of 80 to 90% of chemical contamination.[4] Unpublished mannequin studies indicate that clothing removal reduces contamination by 50 to 70%.  This action is especially necessary 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, bed sheets 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 adsorptive 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 thoroughly clean all skin surfaces 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.  Use of a physiologic solution such as Lactated ringers or normal saline will help to 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. 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 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.  


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Chemical Decontamination - References

References

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Chilcott RP, Managing mass casualties and decontamination. Environment international. 2014 Nov;     [PubMed]
Mis�k J,Pavlikov� R,Ku?a K, Percutaneous toxicity and decontamination of soman, VX, and paraoxon in rats using detergents. Arhiv za higijenu rada i toksikologiju. 2013 Jun;     [PubMed]
Moody RP,Maibach HI, Skin decontamination: Importance of the wash-in effect. Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association. 2006 Nov;     [PubMed]
Braue EH Jr,Smith KH,Doxzon BF,Lumpkin HL,Clarkson ED, Efficacy studies of Reactive Skin Decontamination Lotion, M291 Skin Decontamination Kit, 0.5% bleach, 1% soapy water, and Skin Exposure Reduction Paste Against Chemical Warfare Agents, part 2: guinea pigs challenged with soman. Cutaneous and ocular toxicology. 2011 Mar;     [PubMed]
Lynn DD,Zukin LM,Dellavalle R, The safety and efficacy of Diphoterine for ocular and cutaneous burns in humans. Cutaneous and ocular toxicology. 2017 Jun;     [PubMed]

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