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On-Scene Decon


     The Attack One crew is performing monthly house duties (the dirty ones) and hoping for a call. Most anything would beat this filthy mess! The tones drop, and a full assignment is dispatched for a chemical spill at a downtown facility. The plant site where the call initiated is an older one, with a large number of chemicals used in paper processing and finishing. The dispatcher reports a number of casualties. Staging for all incoming apparatus is established at a distance from the building, upwind and uphill. The hazmat-response team is in the first-arriving group, and Attack One crew members rapidly perform the presuit evaluation on its six hot-zone responders.

     As they complete that, the first responders at the plant lead three people toward the apparatus. These individuals are all coughing and in moderate respiratory distress, so plant supervisors and first responders could not keep them away from the emergency crews. Recognizing the patients' distress and the hazard they might pose, the hazmat responders establish a small victim hot zone in the parking lot. Two members provide quick assistance to the patients while the Attack One crew dons protective splash suits and self-contained breathing apparatus.

     The plant supervisors are unable to identify what exploded and sprayed in the plant. The workers, still in uniform, have liquid material on their faces, chests and arms. Each has several small lacerations and areas of thermal burn with blisters.

     There is no way to set up a formal decontamination area in the middle of the parking lot, but the victims can't be denied care. The rapid plan is to strip the workers of their badly contaminated clothing, wash them with the cleanest water available, flush their eyes with bottled water from Attack One and wrap them in sheets for transportation to the hospital. Their airways will be isolated with high-flow oxygen masks. Personnel from the nearest fire engine in the staging area find the hydrant and establish a water source. They are asked to run the water from the hydrant until it's clearalthough it's cold, it's cleaner than the water in the tanks of the engines. The engine crews hold sheets up to facilitate the victims' stripping, bagging their clothing and rinsing their eyes with the bottled water. The engine crew provides them with the nozzle to wash themselves off, and then they wrap each in a clean sheet and provide oxygen by mask. The three original victims are placed in an area by themselves. One is wheezing, so all are administered albuterol by nebulizer.

     The Attack One crew follows the entry team to the outside of the plant, and as the hazmat team approaches the area where the explosion and spill occurred, they direct more ill and injured workers out to the Attack One crew area. Before they exit, they are asked to remove their clothing, wash off in a shower area and wrap up in a sheet. Eleven workers are so directed. The hazmat crew reports an area in the plant where a mixing vat containing solvent materials had experienced a small explosion. No structural damage or fire had resulted. They obtain chemical samples from the room of origin and some of the victims' soaked clothing for analysis. The chemical meters detect no substances in the ambient air in the room, excluding hydrogen sulfide, carbon monoxide and benzene.

     The Attack One crew sets up for triage. They utilize only one stethoscope, their oldest pulse oximeter and an old BP cuff. The 11 victims have a variety of lacerations, contusions, respiratory irritation and burning eyes. A few are nauseated and complain of headaches. None are in respiratory distress. The workers agree that the usual chemicals were being combined in a vat in the mixing room of the plant when a small explosion occurred, a chemical cloud went up, and some workers were splashed with liquid. The explosion broke lights in the room, which rained glass down on the workers. This was not the expected behavior of any of the chemicals used in the plant.

Incident Management
     The three Ts of multiple-casualty incident management are provided: Triage is assigned to the Attack One crew, including the three initial victims and the 11 later removed from the plant. An EMS crew assumes responsibility for both the Treatment and Transport sectors. All victims are asked to walk through the decontamination area in the parking lot and leave all clothing at the site. The Treatment Sector provides care for the lacerations, eye irrigation and nebulizer treatments to those wheezing. The Transport Sector searches for hospitals to receive the victims. It reports to Command that four hospitals have been identified to do so.

     At this point, Attack One crew members request the opportunity to address this decision. The hazmat team has not yet identified the nature of the materials, and plant chemists are working on the same issue. With an unknown toxin affecting the victims, it would ill-serve both the field and the emergency department staff to have patients spread across the city. It will facilitate communications to have all victims at one hospital, and radio communications then established between Incident Command and ED staff. Command agrees and directs Transport to arrange for all removals to one hospital that can manage the further decontamination and analysis of the victims' signs and symptoms. Blood analysis might also facilitate identifying the toxins.

     As the medic units arrive for transportation, the patients are arranged into groups of three or four for removal. The hospital is asked to prepare for a second, warm-water decontamination before allowing the victims into the ED. Once this is complete and the patients are in the ED, routine vital signs are taken. The victims are all found to have normal pulses and oxygen saturation, but many are found to have elevated carbon monoxide levels. The ED uses the new noninvasive carbon monoxide analyzer, which allows rapid determination of carboxyhemoglobin levels with a finger probe. The consistency of the victims' levels, all in the 15%–25% range, is confirmed with multiple readings. Each also has blood drawn to confirm their carboxyhemoglobin levels using standard laboratory co-oximetry. The victims have all cleared their respiratory symptoms, but now complain of headaches and nausea. Some are also getting confused.

     The emergency physician reports this finding to Command and questions whether a source of carbon monoxide might be present in the plant. Command requests that the hazmat team confirm the negative carbon monoxide finding in the plant using the ambient air meters. Hazmat confirms that finding, and states that they're getting initial information on their analysis that one of the chemicals in the mix was methylene chloride. This chemical, found in paint strippers, is known to produce elevated carboxyhemoglobin toxicity in victims who inhale or ingest it. The plant chemist is questioned about the presence of the material in any of the reagents used that morning and says that chemical was not present, but that one of the materials in use would produce methylene chloride if mixed with a common industrial chemical, hydrochloric acid. Hydrochloric acid is not part of any process at the plant and certainly was not supposed to be in the mixing area, but the plant foreman knew that a shipment of materials received late the previous night had missed the usual check-in process. The chemist goes to the mixing area, checks the materials in the intake zone and finds another container of hydrochloric acid. Apparently, it was packaged in fashion similar to other reagents commonly used in the plant, and was mistakenly unloaded in the prior night's shipment.

     Command radios the hospital with the information regarding the methylene chloride, and the emergency physician confirms the patients' symptoms were consistent with that toxin. Consultation with the regional poison control center confirms the clinical picture, and provisions are made for appropriate patient care using high-flow oxygen.

Victim Outcomes
     The patients who developed confusion in the ED were treated with hyperbaric oxygen. This treatment is typically reserved for patients with neurologic manifestations of carbon monoxide poisoning. All victims had complete recoveries from injuries and illness related to the incident.

Extra Credit Question
     What was the hazard not addressed in this case? Incident Command questioned the plant chemist about the shipment of chemicals from the previous day. If this plant accidentally received hydrochloric acid in place of another chemical, where was the hydrochloric acid supposed to be delivered? This type of mixup likely means another plant also received an unexpected chemical. The chemical distributor was contacted and traced the chain of deliveries. It found another plant site had also received the wrong chemical. The drums were replaced, averting another tragedy.

     Learning Point: Multiple-casualty incidents involving hazardous materials are best managed with the victims going to a minimum number of hospitals.

Case Discussion
     This unplanned reaction precipitating this incident resulted from using a foreign agent in an industrial process. The mixture created a small explosion and released methylene chloride, which is metabolized in humans to produce carbon monoxide. Victims can have profound carbon monoxide toxicity from inhaling this material, most commonly used in paint strippers.

     Victims here required decontamination and treatment at the scene, then a coordinated approach to transportation and communication with a single emergency department. The Attack One crew was aware that multiple-casualty incidents involving hazardous substances are most successfully managed by transporting victims to the same ED. With an exceptionally large number of patients, several EDs may need to participate, but the number should always be as small as possible. When some questions need to be answered at the scene and others at the hospital, fewer sites are better. If the substance turns out to be unusually toxic, it means fewer EDs will have to be taken offline for cleaning.

     In industrial hazardous-materials incidents, it's frequently difficult to problem-solve and identify the chemical at play. As in this incident, significant detective work may be needed to identify the chemical, source and path of danger. Victims in chemical contamination incidents will require management with "wet" decontamination; sometimes several cleansings are beneficial. As with the first three victims in this incident, it may be necessary to establish a rapid method of showering, even if it's less than ideal. Like all contamination incidents, decontamination begins by removing all clothing, jewelry and hardware (glasses, hearing aids, etc.). These items have the largest potential for secondary contamination. Having a set of bags for clothing and smaller bags for valuables facilitates the rapid removal and containment of materials.

     Exchange information efficiently between the scene and the responsible ED. This is facilitated if one knowledgeable member of the hazmat team remains on a radio at the hospital. That individual should be aware of who's working the scene, which party has any information needed and what questions remain to be answered at any time.

     Using the regional poison control center for toxicologic information and coordination is a best practice for incidents where patients are unusually ill or have symptoms not easily explained. The poison control center can also coordinate the exchange of information between different hospitals and out to the broader healthcare community when doctors' offices, clinics and other medical facilities will be seeing the aftermath of a large chemical release.

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