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The Decontamination of people exposed to chemical, biological, radiological or nuclear (CBRN) substances or material

Strategic National Guidance

Full Guidance 754 Kb Frequently Asked Questions Full Guidance (HTML)


Decontamination - Issues for consideration


Decontamination is not an automatic or inevitable response to CBRN incidents. Whether or not to initiate decontamination procedures will depend on the assessment of the nature of the incident by first responders.


Once the decision to decontaminate has been made, the principle is that all casualties, whether injured or not, that are suspected of being contaminated will receive decontamination at the scene. Although this will reduce the number of people self-referring to medical centres people will self-present for decontamination off-site. Medical centres and hospitals should be prepared for this.


If decontamination procedures are initiated, the first objective is to remove the contaminated person from the area of greatest contamination. Usually this will be to the open air and upwind of the incident. If the CBRN release is still in progress and airborne, a risk assessment should be carried out to determine if removing people to a closed area may be more appropriate.


Particular consideration should be given to minimise the exposure of pregnant casualties and carers when the incident involves radiological or nuclear material.


It should be remembered that potential witnesses or suspects might be amongst those being decontaminated.


The careful removal of contaminated clothing will reduce the level of contamination and should, therefore, be a priority. Wherever possible the removal of clothing should be from head to foot, to limit the risk of inhalation of any contaminant.


Special care must be taken to ensure there is no spread of contamination from any clothing to exposed skin.


People who are capable of removing their own clothing and decontaminating themselves should do so, under supervision.


Special care must be taken to reassure and support people who have personal articles such as spectacles or hearing aids removed from them.


All personal clothing and property, whether contaminated or not, must be recorded and linked to an individual. It may contain valuable intelligence or evidence and the continuity of its recording is vital.


In situations where the urgent need for decontamination exceeds the rate at which the Rinse-Wipe-Rinse method can be applied,12 the alternative procedures for mass decontamination (MD)13 should be used.


MD methods include low-pressure water spray from a fire hose, portable showers, the use of large, purpose-built mobile units and the use of fixed facilities away from the scene of the incident. However, the method of decontamination will depend on the type of material that has been released. The identification and assessment of the hazard jointly by the emergency services will determine this.

Removal of casualties from the immediate area surrounding the source of the release


It will be necessary for responders to prioritise the order of evacuation and or rescue depending on the availability of resources or complexity of the situation.


If casualties are either mobile or capable of being removed from the inner cordoned area, trained personnel using appropriate levels of personal protection should carry this out.


Depending on the nature of the incident, an entrapped casualty may have to be partially decontaminated in situ. To facilitate this it may be appropriate to remove clothing and decontaminate exposed skin.

Detailing with non-ambulant casualties


Having removed the non-ambulant casualties from the Hot Zone, limited clinical support and decontamination can start simultaneously at the Decontamination Point(s)


Priority should be given to the decontamination of the face and mouth to allow for early resuscitation to take place before disrobing.

Ambulant casualties using the self decontamination methodology


Ambulant contaminated casualties should remain within the inner cordon outside the Hot Zone until they have been decontaminated.


It is likely that the majority of contamination will be contained on clothing. Suspected contaminated casualties should therefore be encouraged to remove top layers of clothing down to their underwear and this should also be removed if contamination is suspected.


The removed clothing should be treated as hazardous waste and therefore should be double bagged and placed in a controlled area, in accordance with the rules concerning continuity of evidence.


Ideally the correct percentages of detergent should be mixed before its use via temporary showers in the form of spray jets, hose reels or flat fan sprays. However this may not be practicable in many situations and if it cannot be achieved then plain water should be used.


Casualties who have undergone decontamination will need further clinical assessment and may need further treatment.



Risks to CBRN responders include harm from secondary devices, confused, violent or rowdy victims, undetected perpetrators attempting to escape, prisoners under arrest, and police/military weaponry. In the case of mass decontamination, and if there is impatience to enter the decontamination facility, responders should expect public disorder. For these reasons, the decontamination process must be adequately controlled from the outset.

Dealing with fatalities


The dead must at all times be treated with respect and every effort must be made to ensure the dignity of remains. During the immediate response, unless they are presenting a hazard to the living, the dead should where practicable be left in situ.


12See Appendix B

13See section 7 below


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