MOBILE DECONTAMINATION: A New Approach

   Second only to AIDS, protecting society from the effects of chemical and radioactive contamination may well be the dominant public health issue for the balance of this century.

   Chemical contamination and radiation poisoning are problems with significantly different solutions. In the case of radiation exposure, most releases are quickly detected and isolated, and, if circumstances permit, contaminants are washed from personnel and structures with water. If these purges are conducted quickly and thoroughly, and if radioactive materials have not been ingested, the safety of those exposed is virtually assured.

   However, successful decontamination of people exposed to chemical toxins is more complicated. Not only can these toxins be inhaled and ingested, but they also possess adhesive and reactive properties to living tissues. This can hamper complete removal and greatly increase the likelihood of subsequent ill effects.

   The current market. Current onsite decontamination practice in most cases calls for a water deluge performed with fire hoses on personnel and equipment. This method usually is inadequate, given the adhesive nature of many toxins. The rinse-off practice also allows contaminants to run off with the water at the deluge site.

   Many decontamination units available today are set up with one entry and one exit, and often do not offer filtration systems for contaminated water runoff. In addition, most units do not include an equipment decontamination system.

   Contaminants left in rinse water may infiltrate over time into the domestic water supply, creating a health hazard. In addition, failure to test equipment for the presence of residual contamination before returning it for use may lead to a subsequent secondary exposure to personnel, family or friends.

   Meeting the need. After two years of development, a decontamination response vehicle has been patented for use by fire departments, hazardous material response crews and the military. It includes:

The unit can be mounted on a trailer or truck chassis similar to one used as a conventional fire pump. Fully self-contained, the unit can store a large quantity of clean water in a holding tank (as does a fire pump). The unit consists of a multi­stage filtration system; a detergent tank; adjustable high-pressure nozzles; gravity reclamation holding tanks for contaminated water and detergent; an integrated forced-air drying component; a shower; and toilet facilities.

   The system can return filtered water back to the environment or into the clean water holding tanks for reuse. The method chosen (disposal or recycling) usually will depend on the availability of clean water at the site.

   The process. On notification of a chemical incident, the responding agency would dispatch the mobile decontamination unit to a location near the incident site, but far enough away to be considered safe from aerobic contamination. This decision would be based on wind direction and velocity, and other site conditions.

   The first stage in the decontamination process involves the removal of the victim's clothing, tagging those items as hazardous and placing them in isolation containers to be held for later testing. Simultaneously, a similar process is begun on the responder's equipment, which is decontaminated in a separate chamber.

   In the second stage, the victim enters a compartment and is sprayed from all directions with a detergent and water mixture. The type of detergent used is critical, because it must possess cleansing properties far greater than ordinary household soap. It also must contain no abrasives that might break the victim's skin and increase the chances of internal contamination. All waste from this stage passes through a patented, multi­stage filtration system, which removes all contaminants so that the wastewater can be returned safely to the environment through the local sewage system.

   Stage three takes place in a final wash-down compartment, where large quantities of water remove any detergent and all traces of contaminant from the victim. The resulting wastewater also is filtered.

   Stage four is designed to remove all traces of water from the victim's hair and skin, and takes place in a blow-dry compartment. The entire process takes about 20 minutes and permits the victim to proceed safely to diagnosis and treatment, while equipment is returned for reuse.

   Stage five, recommended for units used near refineries and chemical plants, incorporates an on-board diagnostic laboratory containing a Gas Chromatograph/Mass Spectrometer. This device analyzes blood samples to identify specific chemical contaminants, and provide medical staff at the scene and at the receiving hospital with data necessary to initiate treatment.

The chemical decontamination unit can be converted for use as a radiation decontamination center by modifying processing procedures and altering the wastewater flow to bypass the filtration system. The radioactively contaminated wastewater can be routed into a separate tanker adjacent to the unit for transport to a steam burn-off site.

Jerome I. Charyn is a former healthcare administrator and a member of the American Society for Healthcare Risk Management. Jay Shankman has served as a consultant and trainer of emergency responders, and holds the patents on the mobile decontamination units. Shankman is president of National Chemical Decontamination Systems, Inc. (Port Jefferson Station, N.Y.). Publication of this article does not constitute an endorsement by HAZMAT WORLD or its staff of the products described, or claims made by the authors.

58 HAZMAT WORLD     AUGUST, 1989