Decontamination Involving Weapons of Mass Destruction

Incidents involving weapons of mass destruction (WMD) require special consideration involving decontamination. Many responders believe that the standard wet decontamination as taught during our hazardous materials response classes is sufficient, but this is not necessarily the case. Moreover, many believe that a gross decontamination will suffice in an incident involving mass casualties and WMD, but in some cases this does not hold true itself.

Strategic guidelines must be in place for all departments that specifically state which forms of decontamination should be used for certain incidents. The determining factor is the type of agent involved. This article will provide information to formulate a guide in dealing with some of the potential agents.

Chemical Warfare

Chemical warfare agents have been around since the early 1900s. Generally, these agents are broken down into four groups: nerve, blister, blood and choking. The groups are derived from the signs and symptoms produced by each. Each agent has a code associated with it for identification, often times these agents are referred to by their code such as sarin (GB), soman (GD) and VX by its code VX. Decontamination procedures for all of the chemical warfare agents should be accomplished as follows.

Often, we forget that removal of all clothing on the individual is a top priority and may remove as much as 80% of the contaminants. Clothing removal should be accomplished in a systematic manner, cutting along seams when possible and avoiding penetrations in the clothing that may have been made by the dispersion device. The penetrations may be helpful for law enforcement or forensics during the investigation portion of the event. In addition, at minimum, clothing should be double-bagged in plastic liners and kept separate for each individual involved.

The next step is to set up at least two pails, one with a 5% bleach solution and one with clean water. It is imperative that a tepid water solution be used; if not, a problem may occur at the skin level, since hot water tends to cause the pores of the skin to expand and can allow more contaminants into the body. In cold water, the skin pores tend to contract, which allows them to close, entrapping the agent inside.

At this point, several sponges should be available. The patient is then placed on a backboard onto a platform; the platform may be made from a ladder. A basin should be placed under the platform to catch the contaminated water. Start at the patient’s head, utilizing an imaginary line running up and down the nose from the head to the lower part of the trunk. Use a sponge with the bleach solution to sweep, beginning at the midline and swabbing outward, and then follow this immediately with a sponge utilizing the clean water. Repeat this technique from head to toe, including arms. Once the anterior side of the patient has been completed, log-roll the patient and perform the same procedure on the posterior side. At this point, the patient may be checked for further contamination by using M-8 paper or a monitor designed for use with these agents.

Certain agents can be produced with different viscosities. The reasoning behind this is so they may stick and last longer on items such as buildings and ships so that the effects will last much longer and not be dispersed by wind or affected by evaporation. The change in viscosity is relatively easy once the agent is obtained by adding certain materials.

Herein lies the problem with the gross decontamination that many of us were taught over the years. An example would be two engines or ladders side by side and having a contaminated group walk through the water sprays. Agents such as VX and mustard (HN) are easily converted into a jelly-type or oily substance. Consider attempting to wash oil off one’s hands with regular water; it simply does not work. In this case, the best option would be the aforementioned procedure, but if this is not time efficient, the following is recommended: Divide the groups into males and females and have them disrobe, recalling that disrobing can reduce up to 80% of contaminants. At this point, there are two options: have your decon crew begin a hasty decontamination with the bleach solution and send them into the spray; or issue sponges and direct the individuals to attempt to decontaminate themselves, then proceed into the spray. No matter which method is used, the patients should still be checked at minimum with M-8 paper to ensure complete and thorough decontamination has been achieved.

Biological Agents

Biological agents have been in use for thousands of years in one way or another. Commonly known agents are smallpox, anthrax, hemorrhagic fevers, choler, and encephalitis, just to name a few. These agents are still in production, while the development of new agents has slowed. These agents, often referred to as “bugs,” are of concern. Some of these agents are contagious and some are not, but decontamination once again must be handled with the utmost importance.

Decontamination for biological agents has changed drastically since the attacks of October 2001. At first, the recommendations were to use a bleach solution as mentioned above in more of an effort to kill the “bugs” than anything else. However, problems arose such as using too strong a bleach solution, causing skin burns and wounds to patients and responders.

Few biological agents are an inherent problem prior to inhalation, ingestion or penetration, but when the skin is weakened or breached, the “bugs” have a route of entry. It is recommended that a decontamination procedure be followed similar to that for chemical warfare agents, with the exception that a standard soap-type solution be used with water instead of the bleach.

It should be noted that in then-Senator Tom Daschle’s office and in the Arlington, VA, Postal Processing Facility, normal bleach used without dilution did not affect the anthrax in any way. Therefore, the point is – as in washing hands – that the agent will be washed off the body, then later destroyed or disposed of properly in the decon waste water.

Radiological Agents

Decontamination of radiological agents is far different than the agents discussed previously. Decontamination of these patients should be accomplished using a dry decon at minimum twice prior to using a wet decon. Prior to starting the decontamination procedure, a radiological survey meter needs to be used to obtain a background reading. This will give an indication of the natural environmental reading and will be useful during the decon process; it is imperative that it is recorded.

Once again, removing the patient’s clothing and double-bagging it is imperative. At this point, a scan should be done with a radiological survey meter. Special attention and a pause should be made around the nose and mouth area in an effort to check for internal contamination. After a complete survey is accomplished, remove any contaminants by brushing them away from the body; a wet/dry vacuum may be used as long as it contains a HEPA filter.

The patient should then be surveyed once more and the readings recorded. If the reading is less than twice the original background level, then the patient is considered successfully decontaminated. However, if the reading is more than twice the original background level, then a partial dry decon should begin.

A partial dry decon is best accomplished by using spray bottles containing a tepid soap and water solution along with a sponge. In this instance, unlike the chemical warfare procedure, the sponge should be kept dry until used. Use the survey meter to locate the problem area, then apply the soap and water solution afterwards, wiping with the dry sponge. Perform this procedure on all areas. If the survey meter still presents twice the background level, proceed to a full wet decon.

Using tepid water for the aforementioned reasons, thoroughly rinse the patient. Afterwards, thoroughly brush the patient with a soap-and-water solution in the next catch basin, then have the patient proceed to the next basin for another gross wash with tepid water. At this point, perform a check with a survey meter and perform this operation again as necessary.

Conclusion

The above information is strictly a guide. All personnel performing decontamination should be in a minimum of Level B personal protective equipment with National Institute for Occupational Safety and Health (NIOSH) CBRN-compliant self-contained breathing apparatus (SCBA).

As one can see, decon is not simply decon. To do an efficient job, plans and guidelines must be readily available. Training with these plans and guidelines is the key so that in the event they are needed, they are used appropriately.