|All hazardous materials response personnel trained to the technician level and above should be well versed in the concept of risk-based response, as it is a concept that has been prevalent in use in the hazmat response world and in our training curricula for many years now.|
In risk-based response, we tailor our response and the level of chemical protective clothing that personnel entering the hot zone wear to the level of risk presented. By utilizing the concept properly, we can protect our personnel in an appropriate manner from the hazards present while not overtaxing those same personnel with an inordinately elevated level of protection that is in excess of that needed for the situation at hand. While risk-based response is often a topic of hazmat response discussions, we rarely have discussions on a topic that is closely aligned — that of risk-based decontamination. If we can implement our overall hazardous materials responses in such a manner commensurate with the risks presented, why not perform decontamination in a similar manner?
As emergency responders, we train regularly in the techniques of decontamination — often shortened to “decon”. We also try to dispel the myth that decon is the elimination of all contamination. While the removal of all contamination from personnel and equipment at incident scenes is the ideal goal, decon is more properly thought of as contamination reduction since we are actually trying to reduce the level of contamination to an amount that is deemed acceptable.
In general, our technical decontamination process for emergency responders has been fairly static in nature — with a few exceptions such as water reactive materials — since the advent of hazmat response, consisting of the use of an appropriate decon solution (such as detergent) and the use of copious amounts of water and scrubbing with soft-bristled brushes. Although the exact layout of decontamination areas normally differs slightly by agency, the overall concept is usually the same. The main drawbacks of our traditional decon setups and techniques are that a large amount of possibly contaminated runoff is produced and the fact that we are dependent on available water sources (whether traditional water sources or tank water from our fire apparatus), which often results in positioning the decon line at a position further away from the hot zone than what safety would normally dictate.
As was stated earlier in our discussion, what prevents us from applying the methodologies of risk-based response to our decontamination activities? The answer is absolutely nothing — or some might also say the often-heard and often-maligned theory of “we’ve always done it this way.” The decontamination process that we utilize should not be a “one size fits all” approach to all incident situations, but rather a series of approaches that we can pick from as incident conditions allow. Let us next look at the opposite end of the spectrum from the use of traditional water-based decon that is often used in laboratory settings or other similar environments in which spills of small quantities of chemicals are cleaned up while using personal protective equipment (PPE). In those instances, a “dry decon” is often used.
A dry decon consists of the systematic removal of PPE while standing in a large plastic bag or other similar means of containment so that the wearer then steps out of the bag and the PPE is discarded or deconned appropriately if the manufacturer allows. This technique is most appropriate for exposures to contaminants of limited quantity and of limited harm. I am not advocating that as emergency responders we ever use a truly “dry” decon with no water and/or decon solution applied, but rather that we can take some of the aspects of the dry decon technique and apply them in emergency response situations.
The “modified dry decontamination” technique alluded to above may consist of the use of small amounts (a few gallons or less) of water and/or decon solution. For example, let us say that we have responded to a small spill of a liquid product that is not extremely hazardous and does not adhere readily to surfaces. Rather than flow copious amounts of water during decon, we can use spray bottles of water/decon solution mix to selectively spray down the zipper of the hazmat suit and any confirmed/high probability areas of contamination while carefully removing the PPE and limiting contact with the outside of the ensemble.
Gross contamination can also be wiped off with a suitable absorbent at the beginning of the process. Such a process limits the amount of runoff produced that will have to be properly disposed of and allows the decon area to be set up as close as safely possible to the hot zone. One fire department hazmat team described how they effectively used the modified dry decon technique in incidents occurring in high-rise buildings to allow the decon area to be located inside the structure rather than possibly spreading contamination throughout the structure by hazmat personnel egressing to an external decon area.
With any decontamination technique, good communication needs to exist between Decon Group personnel and the Entry, Reconnaissance, and/or Backup Group personnel exiting the hot zone. Decon Group personnel should never learn that the decon process is starting by seeing the personnel that have just exited the hot zone standing at the beginning of the decon line. As Decon Group personnel may be “dressed down” somewhat or at least need to go on air if wearing SCBAs, personnel exiting the hot zone should radio to the exterior that they are exiting before they do so.
Decon Group personnel at the head of the decon line should also clearly and concisely ask arriving personnel their air status (if wearing Level A or B levels of protection), if they have any PPE issues, the identity of the hazardous materials they may have come in contact with, at what location on their PPE were they exposed, the relative probability of contamination, and if they are feeling OK. This information is then used to fine-tune the exact decon actions performed and also prioritize the order in which personnel are decontaminated.
In the risk-based decon realm, the characteristics of the contaminants should drive our decision as to the type and level of decon used. If a contaminant is a relatively hazardous, sticky, thick liquid then a full traditional water-based technical decon should most likely be employed. If a contaminant is a vapor with a relatively high vapor pressure and only the vapor phase was encountered, then it is most likely that the bulk of the contamination has off-gassed by the time that personnel move from the hot zone to the warm zone where the decon area is located. In cases like those just mentioned, a fan can also be employed to aid in the off-gassing process.
An additional benefit of risk-based decon is the reduction (when appropriate) of the number of personnel required for performing the decon process. As we know from experience, personnel performing decon perform some of the hardest work on the hazmat scene as they are suited up for long periods of time performing work and then are required to wait a considerable amount of time at least partially suited up between “rounds” of decon.
Add in environmental conditions that are extremely hot and humid, and the typical seven personnel required for full technical responder decon (a Decon Group Supervisor and six Decon Group personnel) can balloon to 14 or even 21 in order to avoid heat-related issues. If we can safely and effectively perform decon with two, three, or four personnel it will enhance the number of personnel available to perform other functions at the hazmat scene or at least provide for a rotation of personnel into the Decon Group.
I will caution readers that I am not stating that we should abandon our traditional technical responder decon for other means of decon in all situations, but rather that we should use a risk-based approach to tailor the type and complexity of the decon process to the hazards and risks presented at a particular incident. Just as adjustable pattern and smoothbore nozzles both have times and places on the fire ground in which each is most appropriately used to perform fire attack, the risk-based decon approach allows us to choose the right tool for the job at hand in a decontamination sense. We can use such an approach to work just as safely and even more efficiently while performing decontamination procedures. As always, stay safe out there and be sure to visit the North Carolina Association of Hazardous Materials Responders website at www.nchazmat.com s