In recent years much attention has been given to the hardware associated with a hazardous materials response, and yet little attention is given to the idea that all of that equipment, personnel, apparatus and the environment could be contaminated. Recently the selection of suits, site assessments, hazard and risk evaluation, and many other major components of a Haz-Mat response have been conducted quite professionally. Yet the area that is one of the most critical elements in a Haz-Mat response, decontamination, is frequently overlooked or sometimes just plain ignored. Decontamination is so critical that under OSHA 1910-120 the law states: “First responders at the operational level shall…know how to implement basic decontamination procedures. ”First responders must realize that the failure to conduct proper decontamination, even after routine incidents, could result in both short-term and long-term serious health effects.

Even though the response to hazardous materials has evolved into a high-tech field, no one can positively, absolutely, without any question tell you that if you get dirty in chemicals, they can get you clean. If this were an easy task, there would be no disposable protective clothing made.

With this thought in mind, one of the best ways to decontaminate is to avoid being contaminated in the first place. By proper assessment of the site, appropriate levels of protective equipment, good zones, limiting access, establishing decontamination corridors and written standard operating procedures, you will limit your contamination, thus limiting the need for decontamination. If the chemical cannot be avoided then we must consider some other elements, the first being, “when should decontamination be performed?” Factors to consider are: Has an obvious contamination occurred? If there is a suspected contamination, is the product an extremely hazardous or a highly toxic substance? Could decontamination help to control the spread of the contamination? Or to protect people, the environment, or equipment? The second consideration is how much decontamination is needed. A good rule of thumb to use in the field is: “If the product has a high hazard potential, then a high level decontamination is needed.” Another consideration in decontamination is: “How does the product hurt me?” Whether the product is an inhalation, skin or eye absorption, ingestion, or injection hazard will have some bearing on the amount and type of decontamination that is needed.

Another factor to consider in decontamination is how much contamination has occurred. The contact time and concentration of the exposure will be directly related to how dirty you are. Temperature and the size of the contaminants should also be considered. Known product contamination versus an unknown product contamination will dictate decontamination procedures. With known products, when positive identifications have been made, the responder can use decontamination procedures outlined on the MSDS sheet or specific decontamination procedures that may be provided to them by outside agencies. When dealing with unknown products, positive identification is not known. Therefore, no good guidelines on decontamination or specific procedures exist. In dealing with known and unknown contaminations present in the field, we will usually use one or more of the following seven general methods: dilution, absorption, degradation, isolation, disposal, neutralization and solidification. All responders should be familiar with these field practices.

In the actual performance of decontamination, the following key factors must be considered: the placement of the decontamination site, location, controls of the entry and exit points, the establishment of a decontamination corridor, equipment needs, wind direction, closeness to the hot zone, control of the run-off and the handling of hazardous waste. To insure that these priorities and other on-scene problems are addressed, a decontamination officer should be assigned. The responsibilities of the decontamination officer include establishment of the decontamination corridor, a check on the levels of personal protective clothing to be worn, assurance that persons leaving the hot zone have been cleaned, and thorough consultation with the medical officer. By assigning a decontamination officer you have put someone in charge of this operation. They now have the responsibility to get your people clean.

Stages vs. Stations

Many of the procedures we carry out in a hazardous material incident have been borrowed from industry or EPA. Some of their procedures have worked very well for us; others not so well. Today, many Haz-Mat responders are using some form of the EPA decontamination procedures that can include up to nineteen stations. This is not practical, or in many incidents not necessary for an emergency response. To simplify this system, consider stages of decontamination. A stage (by definition in Webster’s Dictionary) is a step in a process. For our use, this means the concept of what must be accomplished at this point before moving to the next step. Coming from the hot zone we could call our people dirty/dirty, moving through the decontamination corridor they become dirty/clean, and eventually exiting the decontamination corridor, clean/clean. Personnel entering decontamination from the hot zone are as dirty as they can be. They are returning from an area where contamination can occur.

Consider The Four Stage Method

Stage One: Solo. Stage One of decontamination consists of a tool drop and a primary wash to remove the gross contaminants. This will include a full outer wash and rinse. Because the entry person is the dirtiest he can be at this point, this stage should be solo. This solo wash can be accomplished by using a shower, PVC washing stall, a portable stall or a garden hose that the entry person can use himself.

Stage Two: Wash, Rinse, Remove Outer Protection…Assisted. Stage Two will consist of a full outer wash and rinse. This will be an assisted wash and rinse using decontamination personnel. This stage should concentrate on the boots and gloves of the individual. Many times they have received a high contamination from walking through or touching the product. With standard firefighting gear a wash and rinse are performed. In chemical protective clothing a wash and rinse followed by the removal of outer bands, tape, outer gloves or boots will be performed. Remember that a wash and rinse followed by a wash and rinse has proven to be very effective.

Stage Three: Wash, Rinse, Remove All Protection…Assisted. Stage Three will include another wash and rinse followed by removal of the protective equipment. This will be an assisted wash, rinse and removal of equipment using decontamination personnel. It is important to note that respiratory protection should be the last item to be removed.

Stage Four: The Person. Stage Four consists of a full body wash, drying and dressing of the individual. This may be performed on-site or off-site. It is incomprehensible that after a chemical emergency we do not shower our people. Supplies like shampoo, soap, scrub brushes, Q-Tips, gowns and slippers must be made available to adequately carry out this stage. Also in Stage Four a medical exam will be performed comparing vital signs taken before entry to vital signs taken after exit.

When the entry involves the use of chemical protective clothing, treatment of heat stress and dehydration of the individual should be a priority. Record keeping and an exposure record should be filled out at this time.

With decontamination being so equipment- and personnel-intensive, it is imperative that it be practiced. Planning, contingencies, and proper equipment and training will prove to be the difference between failure and success. The scene of a hazardous materials incident is no place to rehearse.