Mass Casualty Decon For Terrorist Incidents
BY WILLIAM M. MOULTRIE
Recently, many articles have been written about nuclear, biological, and chemical (NBC) terrorism incidents. Recognizing an incident, donning the appropriate protective equipment, establishing incident command, and summoning additional units are important actions to take, but the most important action is initiating mass casualty decontamination (MCD).
Decon corridors are important in chemical and radiological incidents; they may not be necessary in biological incidents, depending on what the agent is, how it is disseminated, and when the release occurs.
It is relatively easy to establish an emergency decon corridor, but specific scenarios require certain actions and considerations. Proper personal protective equipment (PPE) including SCBA, proper water pressure and volume, proper location relative to the exclusion zones, and victim egress points are among the important concerns.
The Arlington County (VA) Fire Department has been exploring quick, efficient methods for establishing MCD corridors. The methodology explained here was developed in an NBC terrorist exercise held at the Pentagon in May. Approximately 200 soldiers participated as victims and were processed through the MCD described with great success. Arlington County is developing SOPs and tactical plans covering the use of this method should an NBC incident occur.
INITIAL RESPONDER ACTIONS ARE KEY
In most NBC terrorism scenarios, responders have no advance notice of the incident. On arrival, they will hopefully recognize the signs and symptoms of the specific chemical agent employed and don PPE and SCBA.
Next, they should seal off the area and not allow any potentially contaminated victims to leave or any unaffected persons to enter the area. Some victims may flee before units arrive and refer themselves to area medical facilities, and it`s possible that good Samaritans in the area–not knowing the seriousness of the event–will attempt to assist those affected and become victims themselves.
Initiate a command structure, and request early in the incident additional resources, including subsequent alarms for personnel, local/regional haz-mat units, advanced life/basic life support units, and any specialty units available (metropolitan medical strike teams and special emergency response vehicles, for example). Finally, establish an MCD corridor.
In these scenarios, first-arriving units likely will be overwhelmed by the event and implementation of the previously mentioned actions. However, two or three firefighters working together can deploy a preconnected handline, charge the pump and line, and begin directing victims through a makeshift corridor until additional units arrive.
Primarily, MCD is intended to provide large volumes of water at low pressures; volumes in the range of 400 to 500 gpm at 30 to 40 psi are suitable. Too much pressure can be detrimental to victims who have been seriously affected, and too little pressure will provide ineffective fog patterns.
An effective decon corridor can be established by placing pumpers parallel (pump panels facing away from each other) approximately 20 to 25 feet apart (photo 1 on page 78) and incorporating a master stream at the end of the corridor (photos 2, 3). Depending on the water supply pressure, another pumper may be needed at the hydrant to provide minimal pressure. Between 300 and 500 persons can be deconned in as little as 60 minutes.
Two and one-half-inch fog nozzles are attached to the side discharges, positioned to provide fog patterns into the area between the pumpers. If the pumps are equipped with “droop snoot” discharges, remove them or position them so that the fog nozzles are parallel with the ground and the patterns are directed into the space between the pumpers. For pumpers equipped with front preconnects, they may also be used directly on the discharge pipe.
If a ladder truck is available, it can be placed in line with either of the pumpers with the ladder pipe installed. A fog nozzle is placed in service, and the pattern is situated to provide water coverage at the end of the corridor. Variations of this arrangement should work as well. For example, substitute another pumper for the ladder truck, or use four pumpers in parallel pairs of two.
Corridors using this configuration can be established in seven to 10 minutes. The basic concept is that high volumes of water at low pressures in fog patterns should ensure that victims passing through the corridor will be completely decontaminated. Additionally, liquid soap, sponges, and buckets can be placed in the corridor for victims to wash themselves. A diluted bleach solution (.5 percent) has been suggested as the decon solution of choice. Note, however, that a contact time of approximately 15 minutes is necessary for optimal performance–an unreasonable expectation when several hundred victims may be proceeding through the decon line and bleach is not usually readily available in the quantities needed.
Decon corridors should ex-tend from the hot zone nearest the incident site through the warm zone farther away to the cold zone. It is key that the corridor not be too far away from the victims` egress point from the contaminated area. Contaminated victims may have vision difficulties, be coughing/retching uncontrollably, and be unable to travel great distances.
Victims need to be advised of what is expected of them in an NBC incident. Prewritten signs, bumper-mounted PA systems, or bullhorns can be used to direct victims to the corridor and relay instructions to them.
SPECIAL CONSIDERATIONS
Consider the terrain and wind direction. Establish corridors upwind and uphill from the release site (or crosswind if absolutely necessary) with victims traveling through the corridor against the wind and opposite the direction of runoff. Where these standards conflict, use the wind direction as the prevailing guide. The volume of water running in the corridor will quickly disperse any agent washed from victims.
Seasonal and weather conditions are other important considerations. In cold climates, hypothermia can be as much of a problem as the NBC agents.
Have in place SOPs to identify buildings that can be acquired to shelter victims who have been deconned.
Consider transportation assets such as private ambulances and school or municipal buses that can be used to transport victims to medical facilities or hold them before they are transported.
Firefighters must be stationed at key locations in or along the corridor. A minimum of two should be at the front where victims enter and two at the back where they exit. Standard firefighting PPE and SCBA are acceptable ensembles when working in an MCD corridor. If victims can move from an area contaminated with chemical warfare agents, they have not been profoundly affected by the agent.
“Off-gassing” (emanation of agent fumes from victims` clothing) is the primary danger–a respiratory hazard, not a percutaneous one. Firefighters must wear SCBA. In the Tokyo subway incident, doctors were overcome by fumes emanating from the victims and also needed treatment (albeit minimal). Cross-contamination can be reduced by avoiding touching the victims. Structural firefighting ensembles and SCBA are not recommended for entering atmospheres contaminated with unknown chemicals. Level A ensembles are preferred.
Once victims have been deconned, have them proceed to a T3–triage, treatment, and transport–sector. Signs and symptoms will help in assessing victims` levels of contamination and whether they need immediate transport or can be held in a casualty collection area.
RUNOFF
Runoff from chemical agent decon does not necessarily present a problem in these incidents because the small amount of agent disseminated will hydrolyze as it washes through the wastewater system. Responders should recognize that a large amount of agent is not needed to have significant casualties. Flows of approximately 500 gpm can be expected in the MCD during operation. Any agent present will be diluted in this volume of water. If concerns still persist, contact the local pool supplier, and request a load of sodium hypochlorite (pool bleach). This can be flushed behind the runoff to ensure complete destruction of the agent. A more labor-intensive method of controlling runoff is to establish dams/dikes to control the material as it is being pumped into containers for removal and further processing.
Conversely, runoff from a radiological incident must be captured; it will not dissipate in the wastewater system. However, a terrorist incident involving radiological materials is unlikely, because it is extremely difficult to obtain powdered materials that can be effectively and efficiently disseminated.
Most biological scenarios will manifest after the toxin or virus has been disseminated, which may be hours to days later. In these cases, decon will be of little help, since the agent will have been ingested or inspired and will have begun causing damage. If the incident is announced and responders arrive in time to effect decon, the use of .5 percent household bleach will effectively kill the agent, including anthrax. As in the chemical incident, runoff does not present a problem.
The corridor has a number of advantages: It uses equipment firefighters are trained to use, it is readily available, and it can be set up quickly.
Local responders may identify other options for establishing corridors. Whatever the plan, ensure that all responders know their roles, recognize NBC agent contamination, are aware of the need for the decon corridor, and can set up the corridor quickly and efficiently. n
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(1) An effective decontamination corridor can be established by placing pumpers in parallel (pump panels facing away from each other) approximately 20 to 25 feet apart. (Photos by author.) (2) Aerial ladder master streams are an excellent adjunct to the decon corridor. (3) Between 300 and 500 victims can be deconned in as little as 60 minutes.
n WILLIAM M. MOULTRIE is a 25-year veteran and captain with the Arlington County (VA) Fire Department. He has served as a firefighter, an officer with engine and truck companies, a staff assistant to the fire chief, and a public information officer and is a certified haz-mat technician. He is a certified emergency manager with the National Coordinating Council on Emergency Management (NCCEM) and an instructor with the Chemical Biological Defense Command Domestic Training Program and currently serves as deputy coordinator of emergency services for Arlington County.
