Last month, a truck carrying 4,400 gallons of hydrochloric acid collided with a train in Centerville, PA. For several hours, a column of white vapor floated above the wreckage. Emergency responders acted quickly to evacuate residents in the area and clean up the spill.
On a daily basis, thousands of businesses use our nation’s roads and railways to transport hazardous chemicals used for industrial or household purposes. Whether a chemical is released by accident, such as the case in Centerville, or intentionally by rogue assailants, terrorist organizations, or non-state actors the result is the same: large numbers of people could be harmed by inhaling, ingesting, or otherwise coming in to contact with hazardous chemicals. The need to decontaminate an overwhelming number of people has garnered wide interest among policy makers and emergency planners.
ASPR’s Biomedical Advanced Research and Development Authority (BARDA) sponsored a set of scientific studies at the University of Hertfordshire on chemical decontamination. The results of these studies, codified as the Primary Response Incident Scene Management (PRISM) Guidance for Chemical Incidents, will help local emergency management planners and first responders prepare for and respond to disasters involving chemical agents.
PRISM, BARDA’s most recent guidance for decontamination, recommends three steps that will reduce exposure and remove more than 99% of chemical contamination: (1) move quickly away from the hazardous area (if feasible); (2) carefully remove all clothes; and (3) wipe skin with a paper towel or dry wipe.
If done quickly, disrobing reduces contamination by 90 percent (see figure 1).
Figure 1: Relationship between effectiveness of disrobing (arb
1) and time at which disrobing is complete.
2
Implementing dry-decontamination techniques, such as wiping skin with a paper towel, reduces contamination by an additional 9 percent (see figure 2).
Figure 2: Relationship between effectiveness of decontamination (arb) and time at which decontamination is initiated.
Implementing the Three Steps
Prompt, orderly movement away from hazardous areas is key. Inappropriate or delayed evacuation may worsen exposure to hazardous materials.
Once evacuated from the hot zone or safely sheltered, patients should remove their clothes. Removing contaminated clothing limits transfer of contaminant from clothing onto skin and prevents secondary exposure through off gassing of clothing. If possible, cut off clothing rather than pull it over the head. If appropriate cutting instruments are not available, patients should hold their breath and pull clothing away from the face when removing clothes over their heads. Contaminated clothing should be treated as hazardous waste.
To remove hazardous material from the skin and hair, blot exposed skin and hair with any available dry absorbent material, such as paper towels or cloths. Use wet decontamination (e.g., swimming pool showers, sprinklers, or bottled water) when the contaminant provokes immediate skin irritation or is particulate in nature. Carry out these improvised decontamination efforts starting from the head working toward the toes, concentrating on exposed areas such as the scalp (hair), face, neck, arms, and hands. Since chemicals often act rapidly, initiating these actions as soon as possible—even on your own if instructed to do so—may be the most important factor in preventing illness.
Responders should carry out a dynamic risk assessment at the scene to determine if gross decontamination, e.g., the ladder pipe system, and technical decontamination, the use of specialized decontamination units, should be conducted to decontaminate patients further. Drying the skin after using the ladder pipe system or any other type of showering is a key step in removing contaminants from the skin surface. Treat used towels as contaminated waste.
Addressing the Challenges to Implementation
The biggest challenge for responders may be getting people to cooperate. Asking patients to take off their clothes can lead to anxiety, non-compliance, and security issues at the scene of an incident. Good communication is key to acquiring the trust and cooperation of patients. Provide information about why disrobing and decontamination are necessary, in terms of protecting oneself and other people and places, including home and family. Performing wet decontamination on clothed individuals will result in the transfer of contaminant to the skin. Also provide privacy or modesty protections—such as blankets or plastic sheets—when possible.
Another challenge is working with patients who are unable to comply with instructions due to mental impairment, physical disability or simply an inability to understand the spoken language. Plans need to be in place to rapidly identify and provide these patients appropriate assistance.
If you are not familiar with PRISM and the guidance it provides local community responders, check it out today. Also available for download is the complementary set of patient decontamination principles: Patient Decontamination in a Mass Chemical Exposure Incident: National Planning Guidance for Communities. Additional resources about chemical decontamination are available through ASPR TRACIE, including technical assistance specialists for one-on-one support and a peer-to-peer discussion board.
1The arbitrary unit expressing effectiveness (arb) gages 1 as being completely effective and .2 as being least effective.
2Primary Response Incident Scene Management (PRISM) Guidance for Chemical Incidents, p.21 & 31
