Dry decontamination

^[1]Dry decontamination is a method of decontaminating (or removing contaminants like chemicals, biological particles, or other liquids, gasses, or solids) that requires no water or other liquids. Decontamination is an essential job duty of hazmat responders as it protects victims from harmful reactions to the contaminants.^[2]

Dry decontamination is a relatively recent addition to decontamination and is especially useful in cold weather conditions^[3] or when water is scarce or difficult to transport. Dry decontamination reduces the size and manpower requirements of the decontamination line and eliminates the issue of having to purchase excess equipment that becomes ineffective due to storage or infrequent use.^[4]

Dry decontamination methods

Dry decontamination is usually performed after the removal of clothing and before a shower (when available). There are five different types of dry decontamination, each of which can be used in conjunction with others to remove up to 100% of all suspected contaminants:^[5]

1. Scraping
2. Absorbent Materials
3. Adsorbent Materials
4. Vacuuming
5. Pressurized Air

Scraping

Scraping is a process of decontamination in which the bulk contaminant is removed from the victim or environment using a spatula, wood tongue depressor, or other handheld implement. Scraping works best with viscous liquids and solids.

Absorbent materials

Absorbent materials are specifically made to absorb (or capture and contain) contaminants. Absorbent materials include FiberTect,^[6] RSDL, Fuller's earth, flour, baking soda, paper towels, etc., all of which absorb hazardous materials from the victim. After absorption is completed using an absorbent material and immediate danger has passed, the contaminated surface should be blotted with a wet paper towel. An absorbent material increases in volume when a contaminant is absorbed.^[7]

FiberTect

FiberTect is a multi-layer nonwoven composite fabric that absorbs and adsorbs chemical, biological, and radiological contaminants. It is made of two layers of polyester with an inner layer of fibrous activated carbon.^[6] The three layers are needled-punched to form a single fabric that allows the material to be structurally sound while creating void spaces for better absorption and adsorption.^[5] FiberTect is available in wipes or mitts, which remove up to 90% of contaminants.^[8]

RSDL

RSDL (or Reactive Skin Decontamination Lotion) consists of an absorbent sponge applicator and a lotion that neutralizes toxic agents. RSDL removes or neutralizes chemical warfare agents, T-2 toxins, and pesticides.

Fuller's earth

Fuller's earth is any clay material that has the ability to absorb oil, grease, etc. without chemical treatment. It is also used for filtering, clarifying, decoloring, and as a filler in paint. It is used by the military and first responders to decontaminated contaminated clothing and equipment.

Adsorbent materials

Adsorbent materials adhere to and encapsulate contaminants on various surfaces. Adsorbent materials do not increase in volume when a contaminant is absorbed.^[5]

Vacuuming

Vacuuming physically removes solid materials from victims and the contaminated environment. Vacuuming should only be done when the victim and all people in the vicinity are wearing respiratory protection and the usefulness of vacuuming can be limited by the availability of supplies, equipment, and electricity.

Pressurized air

Pressurized air uses low-pressure air streams to remove solid, dry contaminants from equipment and the environment. Like with vacuuming, the use of pressurized air should be limited to conditions when all people in the contaminated area are wearing personal protective equipment (PPE). The use of pressurized air is often not recommended because there are many hazards associated with the method, including respiratory and skin damage.^[5]

Dry decon vs. wet decon

Advantages of dry decontamination

Dry decontamination reduces concerns associated with cold weather decontamination while also speeding up the decontamination process by allowing victims to self-decontaminate (or be decontaminated by a first responder with minimal cross contamination). In addition, some contaminants are water-reactive and wet decontamination methods may only increase the potential hazards.^[7]

Time Effectiveness

The deployment of a dry decontamination system allows the victim to assist in his/her own decontamination. In addition, dry decon operations are expedited by allowing for the quick removal of contaminants from the victim's skin, which reduces the amount of time a victim is in contact with the contamination (which therefore reduces the potential harm caused).

Cold weather decontamination

Because hypothermia when conducting decontamination in temperatures below 36 °F, dry decontamination can be an effective solution that prevents more casualties as a result of hypothermia.^[2] Other sources recommend wet decontamination be avoided in external temperatures of below 65 °F to avoid adverse effects of cold shock.^[5]

Logistical Issues

Wet decontamination lines require not only a water source, but occasionally electricity for deployment. As a rule, dry decontamination is faster both in deployment and clean-up as it does not require an immediate water supply, contaminated water collection basin, resources (like hoses, nozzles, shelters, and other large pieces of equipment), or a large number of personnel.

Mass casualty decontamination

Large scale decontamination often involves civilians who, unlike soldiers and responders, are not trained in decontamination methods. Currently, wet decontamination is most frequently used in large scale decontamination efforts, during which civilians are directed by soldiers and responders to shower (usually with water and a detergent or bleach). Dry decontamination is proving to be a safer, more effective method of decontamination for large scale incidents.^[9]

References