131: Hazardous Materials Incident Response

A hazardous material (hazmat) can be any xenobiotic (solid, liquid, or gas) with the potential to harm. Typically, we are most concerned about xenobiotics that can harm people, although a hazardous material may also harm other living organisms, the environment, or property. Outside of the United States, hazardous materials are often referred to as dangerous goods.

A “hazmat incident” implies that there was an unplanned or uncontrolled release of, or exposure to, a hazardous material. These terms are also used interchangeably; here we will use hazardous materials. Although there are no specific requirements for an event to be considered a hazardous materials incident, typically there must be the potential for many people or a large area to be affected; otherwise, all toxicologic exposures would fall into this category. Therefore, a hazardous materials incident falls within the larger disaster management framework within a community.

Hazardous materials include chemical, biologic, and radiologic xenobiotics. In fact, a single event could provide exposure to multiple xenobiotics. Complicating matters, the incident response required for chemical, biologic, or radiologic xenobiotics may differ substantially depending on many factors. For instance, an envelope containing a white powder suspicious for containing anthrax spores that is opened in an office might require decontamination of the exposed people and environment. However, the release of the same anthrax spores surreptitiously at multiple sites may not be recognized until days later because of the delayed onset of symptoms. Certainly, a very different emergency response would be required. Emergency managers and health care professionals must consider all possibilities and adjust the incident response based on the specific xenobiotics involved, the route of the exposure and other variables such as time. This chapter discusses the basic principles used for a confined and quickly identifiable hazardous materials incident.

In general, a hazardous materials incident response focuses on the care of patients exposed to xenobiotics in the prehospital setting, prepares for multiple casualties, and emphasizes patient decontamination while at the same time trying to prevent exposure and contamination of first responders and health care professionals.

Every emergency response has the potential to involve hazardous materials and therefore first responders must always appreciate this possibility. A simple motor vehicle collision often releases gasoline into the environment. A victim pulled from a burning building may have carbon monoxide poisoning. A terrorist may contaminate an explosive device with radioactive material (eg, dirty bomb). The early identification that an event involves a hazardous material will allow for better patient care.

Preparedness requires the planning of actions to be taken when a disaster occurs, as well as the practicing with mock exercises of these actions. Preplanning is critical to limit damage from an event, and numerous such hazardous materials incident response plans exist. The recovery phase occurs after the immediate needs and threats to human life are addressed in the response phase and entail the restoration of property, infrastructure, and the environment.

The response phase includes the mobilization of appropriate resources and the coordinated management of the incident. A hazardous materials incident response must include the containment of the xenobiotic followed by neutralization, removal, or both. Typically, such a response includes multiple trained professionals from various agencies, often including the emergency medical services (EMS), fire departments, police departments, environmental protection agencies, and other first responder emergency services personnel. In fact, major hazardous materials events, especially those considered purposeful or the result of a terrorist act, may have responders from multiple federal, state, and local agencies, each with equipment and vehicles, and hundreds of personnel at the scene. These events can be chaotic until control and coordination are achieved.

Disaster management has four phases: planning, response, mitigation, and recovery. Mitigation measures are plans and efforts that attempt to prevent or reduce the effects of a potential hazard from becoming a disaster or minimizing the effects of a disaster if it has already occurred. One example of a mitigation measure is to use a secure container to prevent leakage of a chemical that is to be stored.

Initial disaster management is provided by local resources and agencies with progressive escalation to county, state, and federal agencies as necessary. The US Federal Emergency Management Agency (FEMA) within the US Department of Homeland Security is the lead federal agency for emergency management in the United States.

Medical professionals are a necessary part of all hazardous materials incident responses because patient assessment and treatment are typically the highest priority. However, as with all mass casualty events, physicians, and other health care professionals, even those highly trained in emergency medicine, toxicology, or hazardous materials response, must not respond to the location of the event unless they are part of a planned response team that has been requested to respond to the incident. Unsolicited medical personnel at the scene of a hazardous materials incident, although well intentioned, may actually harm the coordinated response and interfere with lifesaving efforts.

Limiting the loss of life is dependent on all responding agencies and personnel working efficiently and effectively together. The coordination of federal, state, and local governments is mandated by a National Incident Management System (NIMS).¹⁰ Interoperability and compatibility among on-scene assets are dictated by the Incident Command System (ICS), which consists of an organizational hierarchy and defines the necessary management components of the overall incident, including mechanisms necessary for controlling personnel, operations, and communications.

The request for mobilization, management, and utilization of volunteer medical personnel at the scene of a disaster should be planned for in advance for those events that might benefit from these resources.³⁰ Unsolicited medical professionals lack the communications equipment necessary to work within a multiagency coordinated operation. They often function outside the organized ICS. They may lack or be unaware of the necessary personal protective equipment (PPE). The medical treatments they provide may lack the oversight and protections required for the provision of medical care. These environments are, by definition, hazardous, and freelance medical personnel may in turn become patients themselves, thereby adding to the burden of on scene rescuers. Furthermore, although a patient affected by a specific hazardous material may have the same physical findings and treatment indications whether at the hazardous materials scene or at the hospital and although the same toxicologic principles apply, these differences in location often require variation in the medical decisions made and the actual care provided. Typically, disaster plans incorporate the utilization of local medical assets such as hospitals and clinics. Therefore, communities are best served if medical providers respond to their respective institutions during an incident.

After the release of a hazardous material, there must be a notification to emergency response personnel. Typically, someone witnesses the incident itself, such as a motor vehicle collision in which a tanker trailer is breached, or some resultant effects of the release, such as a fire, and the individual then activates the emergency response system by calling 9-1-1. Alternatively, an established detector may activate an emergency response to a hazardous materials incident even before there are easily observable results of the release.

The first responders may not be aware that an incident is hazardous materials related when responding. For instance, they may be assigned to respond to an unconscious patient, unaware that the cause of the medical emergency was a chemical exposure. Although every emergency response cannot be assumed to have a hazardous materials etiology, emergency responders must always remain vigilant for such situations.

Extensive knowledge, training, and judgment are required for all emergency personnel who respond to hazardous materials incidents. There are some basic paradigms followed for a hazardous materials response. Personnel should approach the scene from uphill and upwind if possible. They should not rush in to try to help patients because the rescuer may become an additional victim if exposed. It is important to establish a perimeter to secure the scene while evacuating those not contaminated, thereby preventing additional people from being exposed or contaminated. The identification of material, establishment of containment or safety zones, wearing of PPE, decontamination, and medical management of patients are discussed later. Other considerations include hazardous materials resources available, the need for escalation to other emergency response agencies, weather conditions, terrain, confinement of the release, intentionality, and the need for rapid rescue and evacuation of casualties.

Identification of Hazardous Materials

If the identity of the xenobiotic(s) is known before arrival at the scene, then research can begin while the responders are still en route with reviews of the physical, chemical, and toxicologic properties of the xenobiotic. If the xenobiotic is not known before arrival at the scene, then efforts to obtain this information should begin as soon as safely possible.

The identification of the specific xenobiotic(s) involved is of highest priority because many of the response components depend on the properties and potential health effects of the xenobiotic itself. Whether the incident involves a transportation element such as a rail car or road trailer or is at a fixed location such as a factory or medical facility, all available information must be used toward material identification, including placards, container labels, shipping documents, material safety data sheets (MSDS), detector devices, knowledgeable persons at the scene, patient signs and symptoms, and even odors at the scene such as the rotten egg smell of hydrogen sulfide.

Because many hazardous materials are transported via rail car or road trailer, emergency response personnel must always maintain a high index of suspicion when responding to a transportation incident. In the United States, first responders are required to be familiar with the use of the Emergency Response Guidebook, which is an aid for quickly identifying the hazards of the material(s) involved in a transportation incident.⁴⁴

Hazardous materials may be categorized in various ways, often grouped by their harm-causing property. For instance, hazardous materials may be radioactive, flammable, explosive, asphyxiating, pathogenic, and biohazardous.

The xenobiotics most commonly encountered at hazardous materials incidents vary from one locale to another and are predominately determined by the major industries in a particular area.^47,48 For example, pesticides are the most commonly encountered class of hazardous materials in Fresno County, California, whose major industry is agribusiness.⁴⁸ Although most hazardous materials incidents involve only one hazardous material, more than one hazardous material may be encountered at a given incident. One study described 107 hazardous materials incidents involving a total of 156 materials.⁴⁸

The vast majority of consequential hazardous materials incidents are caused by gases, vapors, or aerosols. In one study, four of the five most commonly encountered individual chemicals were ammonia, phosphine, sulfur oxides, and hydrogen sulfide.⁹ The important implication for decontamination is that gases do not usually contaminate people secondarily because they do not adhere to patients. Therefore, patients exposed only to gases generally do not require skin decontamination to prevent secondary contamination, and much greater efficiency is possible in patient care at gas, vapor, and liquid hazardous materials incidents. Inhalation is the most common route of exposure at hazardous materials incidents and was the route of exposure at 73% of the hazardous materials incidents, accounting for 76% of the exposed patients described in one study.^8,9

Because the number of hazardous materials is so large, it is efficient to group hazardous materials according to their toxicological characteristics. Various classification systems have been devised. The International Hazard Classification System (IHCS) is the most commonly used system (Table 131–1).^44,47 Individual hazardous materials studies commonly use their own classification systems, emphasizing the toxicodynamic effects of hazardous materials such as systemic asphyxiants or highlighting individual chemicals such as ammonia or chlorine or general classes of chemicals such as acids, bases, or volatile organic compounds.^8,9

Chemical Names and Numbers.

Chemical compounds may be known by several names, including the chemical, common, generic, or brand (proprietary) name.^5,6 A chemical may be the sole substance in a given hazardous material or one of several compounds in a mixture.

The Chemical Abstracts Service (CAS) of the American Chemical Society numbers chemicals to overcome the confusion regarding multiple names for a single chemical. The CAS assigns a unique CAS registry number (CAS#) to atoms, molecules, and mixtures. For example, the CAS# of methanol is 67–56–1.^35,36 These numbers provide a unique identification for chemicals and a means for crosschecking chemical names. Identifying a chemical by name and CAS# is critical because one must be as specific as possible about the hazardous material in question. Trade or brand names can be misleading. The MSDS describing a product usually lists the chemical name, the CAS#, and the brand name.²⁹

Vehicular Placarding: UN Numbers, NA Numbers, and PIN.

Substances in each hazard class of the IHCS (Table 131–1) are assigned four-digit identification numbers, which are known as United Nations, North American, or Product Identification Numbers, and are displayed on characteristic vehicular placards. This system is used by the US Department of Transportation in the Emergency Response Guidebook.⁴⁴ The IHCS assigns a chemical to a hazard class based on its most dangerous physical characteristic, such as explosiveness or flammability. Other potential hazards of a xenobiotic, such as its ability to cause cancer or birth defects, are not considered. This system provides very little guidance in treating poisonings caused by hazardous materials.

National Fire Protection Association 704 System for Fixed Facility Placarding.

Fixed facilities, such as hospitals and laboratories, use a placarding system that is different from the vehicular placarding system. The National Fire Protection Association (NFPA) 704 system is used at most fixed facilities.³¹ The NFPA system uses a diamond-shaped sign that is divided into four color-coded quadrants: red, yellow, white, and blue. This system gives hazardous materials responders information about the flammability, reactivity, and health effects, as well as other information, such as the water reactivity, oxidizing activity, or radioactivity.

The red quadrant on top indicates flammability; the blue quadrant on the left indicates health hazard; the yellow quadrant on the right indicates reactivity; and the white quadrant on the bottom is for other information, such as OXY for an oxidizing product, W for a product that has unusual reactivity with water, and the standard radioactive symbol for radioactive substances.

Numbers in the red, blue, and yellow quadrants indicate the degree of hazard: numbers range from 0, which is minimal, to 4, which is severe, and indicate specific levels of hazard.

Similar to all placarding systems, this one also has limitations. It does not name the specific hazardous substances in the facility and gives no information about the quantities or locations of the materials.

United Nations.

Recognizing that the transport of chemicals often occurs internationally and that the labels and MSDS often have different information in different countries, the United Nations developed a chemical classification system in an attempt to harmonize an approach to classification and labeling. The Globally Harmonized System of Classification and Labelling of Chemicals classifies substances and mixtures by their health, environmental, and physical hazards.

CHEMTREC is a service of the Chemical Manufacturers Association providing continuous essential chemical information with regard to shippers, products, and manufacturers. CHEMTREC is available at 800–424–9300 or at http://www.chemtrec.org at no charge, 24 hours a day. Details of an incident are relayed to the shipper’s or manufacturer’s 24 hour emergency contact, and they in turn are linked to hazardous materials incident responders. Technical data are available on handling the substance(s) involved, including the physical characteristics, transportation, and disposal.

A regional poison center is another valuable source of information. Other information sources include local and state health departments, the American Conference of Governmental and Industrial Hygienists, Occupational Safety and Health Administration (OSHA), National Institutes of Occupational Safety and Health (NIOSH), Agency for Toxic Substances and Disease Registry, and Centers for Disease Control and Prevention.^{1,2,3,35,36,38}

Exact identification is desirable but not always possible. Hazardous materials responders may be able to classify the hazardous material into one of several major toxicologic classes by identifying a hazardous materials toxidrome that allows them to reasonably treat the patients and protect themselves and others. For example, do patients have irritation of the mucous membranes and upper airway caused by a highly water-­soluble irritant gas? Do the patients exhibit signs of asphyxia with major central nervous system (CNS) or cardiopulmonary signs and symptoms? Do patients exhibit signs of cholinergic excess caused by organic phosphorus compounds or carbamate poisoning? Do patients exhibit chemical burns compatible with corrosives? Do patients have the odor of solvents with signs of CNS depression and cardiac irritability compatible with exposure to hydrocarbons or halogenated hydrocarbons?

Also, even when the exact identity of the hazardous material is not known, what is usually known is the physical state of the material, that is, solid, liquid, or gas. Airborne xenobiotics potentially mean many more victims. Airborne xenobiotics include not only gases and vapors but also the liquid suspensions (fog, aerosols, and mists) and the solid suspensions (smoke, fumes, and dusts).

Exposure and Contamination

A person may have received an external exposure to hazardous materials and may be at risk for the resultant health consequences even though he or she may not to be contaminated by the hazardous materials. For instance, a person may be temporarily irradiated by an exposure to a radioactive source. After exposure, a hazardous material may remain on a victim (external) or within a victim (internal). For instance, if radioactive materials (usually in the form of dust particles) are on the body surface or clothing (ie, contamination has occurred), and the person will continue to have exposure until decontamination occurs.

Primary contamination is contamination of people or equipment caused by direct contact with the initial release of a hazardous material by direct contact at its source of release. Primary contamination may occur whether the hazardous material is a solid, a liquid, or a gas. ­Secondary ­contamination is contamination of health care personnel or equipment caused by direct contact with a patient or equipment covered with adherent solids or liquids that have been removed from the source of the hazardous material spill.

The state of matter will help health care professionals determine whether the hazardous material presents a significant risk of secondary contamination and whether decontamination of the skin and mucous membranes is necessary. Secondary contamination generally occurs only with solids or liquids. In general, patients or equipment covered with adherent solid or liquid hazardous materials, including chemical, biologic, or radiologic agents, should be decontaminated before transportation to prevent downstream contamination of health care professionals and equipment. An exception to the principles of limited need for cutaneous decontamination for those exposed to gas is a patient whose sweaty skin was exposed to a highly water-soluble irritant gas such as ammonia that dissolves in sweat to produce corrosive ammonium hydroxide. In this case, the primary purpose of decontamination is to prevent or treat the patient’s chemical burns caused by the caustic action of aqueous ammonium hydroxide on perspiring skin rather than to prevent secondary contamination of rescuers. Aerosols are airborne xenobiotics that are not gases. Aerosols are suspensions of solids or liquids in air, such as solid dusts or liquid mists, that can cover victims with these adherent solids or liquids, which can effect secondary contamination. These patients require decontamination to prevent secondary contamination.

Emergency personnel and equipment can become contaminated at hazardous materials incidents.^{12,20,21,22,47,48,51} For example, in one study, contamination occurred to one ambulance that drove through a puddle of liquid organic phosphorus pesticides that had spilled from a crashed exterminator truck. This ambulance was responding to a call for a “motor vehicle crash.”⁴⁸

Hazardous Materials Site Operations

Limiting dispersion of the hazardous material is critical to prevent further ill consequences. The physical state of a material determines how it will spread through the environment and gives clues to the potential route(s) of exposure for the material. Unless moved by physical means such as wind, ventilation systems, or people, solids will usually stay in one area. Solids can cause exposures by inhalation of dusts, by ingestion, or rarely by absorption through skin and mucous membranes. Solids that undergo sublimation, changing directly from a solid into a gas without passing through the liquid state, can give off vapors that may cause airborne exposure. Only two commonly encountered solids sublime, dry ice (CO₂) and naphthalene. A vapor is defined as a gaseous dispersion of the molecules of a substance that is normally a liquid or a solid at standard temperature and pressure (STP), that is, 32°F (0°C = 273°K) and 1 atm (760 torr = 760 mm Hg = 14.7 psi). Uncontained liquids will spread over surfaces and flow downhill. Liquids may evaporate, creating a vapor hazard.

The vapor pressure (VP) is useful to estimate whether enough of a solid or liquid will be released in the gaseous state to pose an inhalation risk. VP is defined essentially as the quantity of the gaseous state overlying an evaporating liquid or a subliming solid. The lower the VP, the less likely the xenobiotics will volatilize and generate a respirable gas. Conversely, the higher the VP of a chemical, the more likely it will volatilize or generate a respirable gas. Water has a VP of approximately 20 mm Hg at 70°F (21°C), and acetone has a VP of 250 mm Hg at the same temperature. Therefore, acetone evaporates more rapidly than water and poses more of an inhalation risk. Standard reference texts (eg, NIOSH Pocket Guide to Chemical Hazards Merck Index) list VPs for commonly encountered chemicals.^35,36,44

Hazardous Materials Scene Control Zones.

Scene management is a fundamental feature at a hazardous materials incident. It is almost always necessary to isolate the scene, deny access to the public and the media, and limit access to emergency response personnel to prevent needless contamination. Three control zones are established around a scene and are described by “temperature,” “color,” or “explanatory terminology” (Table 131–2 and Fig. 131–1). NIOSH, the US Environmental Protection Agency (EPA), and most US prehospital and hospital health care professionals use the temperature terminology system.³⁶

The hot zone is the area immediately surrounding a hazardous materials incident. It extends far enough to prevent the primary contamination of people and materials outside this zone. Primary contamination may occur to those who enter this zone. In general, evacuation—but no decontamination or patient care—is carried out in this zone, except for opening the airway and placing the patient on a backboard with spine precautions. This is because rescuers are generally hazardous materials technicians who wear level A or B suits that severely limit their visibility and dexterity. In specific situations, antidotes may be administered via autoinjectors as in the case of nerve agent antidotes.

The warm zone is the area surrounding the hot zone and contains the decontamination or access corridor, where victims and the hazardous materials entry team members and their equipment are decontaminated. It includes two control points for the access corridor. Many consider initiating therapy at this stage, particularly for chemical weapons, events where multiple casualties are involved.

The cold zone is the area beyond the warm zone. Contaminated victims and hazardous materials responders should be decontaminated before entering this area from the warm zone. Equipment and personnel are not expected to become contaminated in this zone. This is the area in which resources are assembled to support the hazardous materials emergency response. The incident command center is usually located in the cold zone, and there is greater ability to provide patient care there. Care provided in this zone includes the primary survey and resuscitation with management of airway (with cervical spine control), breathing, circulation, disability, and exposure with evaluation for toxicity and trauma (ABCDE). Definitive care also includes antidotal treatment for specific poisonings.

Personal Protective Equipment

A critical goal of hazardous materials emergency responders is protecting themselves and the public. Safeguarding hazardous materials responders includes wearing appropriate PPE to prevent exposure to the hazard and prevent injury to the wearer from incorrect use of or malfunction of the PPE equipment.^26,37

PPE can create significant health hazards, including loss of cooling by evaporation, heat stress, physical stress, psychological stress, impaired vision, impaired mobility, and impaired communication. Because of these risks, individuals involved in hazardous materials emergency response must be trained regarding the appropriate use, decontamination, maintenance, and storage of PPE. This training includes instruction regarding the risk of permeation, penetration, and degradation of PPE. PPE with a self-­contained breathing apparatus (SCBA) with a fixed supply of air significantly limits the amount of time the wearer can operate in the hot zone, usually about 20 minutes.

Levels of Protection.

The EPA defines four levels of protection for PPE: levels A (greatest protection) through D (least protection). The different levels of PPE are designed to provide a choice of PPE, depending on the hazards at a specific hazardous materials incident (Table 131–3).

Level A provides the highest level of both respiratory and skin (clothing) protection and provides vapor protection to the respiratory tract, mucous membranes, and skin. This level of PPE is airtight, fully encapsulating and the breathing apparatus must be worn under the suit.

Level B provides the highest level of respiratory protection and skin splash protection by using chemical-resistant clothing. It does not provide skin vapor protection but does provide respiratory tract vapor protection. Some hospitals have specially trained health care professionals who wear level B PPE when decontaminating patients presenting to the hospital. However, the majority of hospitals are training their frontline emergency department (ED) health care professionals to wear level C PPE when decontaminating contaminated patients who present to the hospital.

Level C protection should be used when the type of airborne ­xenobiotic is known, its concentration can be measured, the criteria for using ­air-purifying respirators are met, and skin and eye exposures are unlikely. Level C provides skin splash protection, the same as level B; however, level C has a lower level of respiratory protection than levels A and B.

Level D is basically a regular work uniform. It should not be worn when significant chemical respiratory or skin hazards exist. It provides no respiratory protection and minimal skin protection. Level D was specifically developed to show what not to wear for chemical protection.

Personal Protective Equipment Respiratory Protection.

Personnel must be fit tested before using any respirator. A tiny space between the edge of the respirator and the face of the hazardous materials responder could permit exposure to an airborne hazard. Contact lenses cannot be worn with any respiratory protective equipment. Corrective eyeglass lenses must be mounted inside the face mask of the PPE. The only exception to these general rules are the use of hooded level C powered air purifying respirators (PAPRs) that do not require fit testing and allow individuals to wear their own eyeglasses within the hooded PAPR. This is the reason that most US hospitals prefer hooded PAPRs for their ED personnel who must decontaminate patients.

Level A PPE mandates the use of a SCBA. A SCBA is composed of a face piece connected by a hose to a compressed air source. An open-circuit, positive-pressure SCBA is used most often in emergency response and provides clean air from a cylinder to the face piece of the wearer, who exhales into the atmosphere. Thus, a higher air pressure is maintained inside the face piece than outside. This affords the SCBA wearer the highest level of protection against airborne hazards because any leakage will force air out of the face piece and not allow airborne hazards to enter against the higher pressure within the face piece. Disadvantages of the SCBA include its bulkiness and heaviness and a limited time period of respiratory protection because of the limited amount of air in the tank.

A supplied-air respirator (SAR) may be used in level B PPE and differs from SCBA in that air is supplied through a line that is connected to a source located away from the contaminated area. Only positive-pressure SARs are recommended for hazardous materials use. One major advantage of SARs over SCBA is that they allow an individual to work for a longer period. However, a hazardous materials worker must stay connected to the SAR and cannot leave the contaminated area by a different exit.

An air-purifying respirator (APR) may be used in level C PPE and allows breathing of ambient air after inhalation through a specific purifying canister or filter. There are three basic types of APRs: chemical cartridge, disposable, and powered air (PAPR). Although APRs afford the wearer increased mobility, they may be used only where there is sufficient oxygen in the ambient air. The chemical cartridges or canisters purify the air by filtration, adsorption, or absorption. Filters may also be used in combination with cartridges to provide increased protection from particulates such as asbestos. Powered devices reduce the work of breathing which can significantly limit an individual’s performance while wearing PPE.

Decontamination

A major goal of the initial hazardous materials response is the decontamination of contaminated victims. Not only does decontamination reduce the health consequences for the victim (by reducing absorption or exposure time) but also prevents secondary contamination. Decontamination of equipment, the environment, and the entire area (ie, hot zone) may also be necessary but is secondary to the decontamination of victims.

An estimated 75% to 90% of contaminants may be removed simply by removing the victim’s clothing and garments. Subsequent decontamination is most commonly accomplished by using water to copiously irrigate the skin of a victim, thereby physically washing off, diluting, or hydrolyzing the xenobiotic. However, the water solubility of a hazardous material must be considered to determine whether water alone is sufficient for skin decontamination or whether a detergent must also be used. The general rule regarding solubility is that “like dissolves like.” In other words, a polar solvent, such as water, will dissolve polar substances such as salts. For example, the herbicide paraquat is actually a salt—paraquat dichloride—that is miscible in water. Therefore, if a patient’s skin is contaminated with paraquat, copious water irrigation is sufficient for skin decontamination. A mild liquid detergent is acceptable but is not necessary. On the other hand, a nonpolar solvent, such as toluene, is not water soluble and is immiscible.^35,36 Therefore, if a patient’s skin is contaminated with toluene, water irrigation alone may be insufficient for decontamination, and a mild liquid detergent is also necessary.^35,36 Furthermore, copious water may not be available at the site, thereby requiring rescuers to ration the supply and minimize irrigation using the least amount of water necessary. Some solid chemical contaminants may react with water and thereby cause an increased hazard if water used for decontamination. Such xenobiotics may be better removed mechanically by physically wiping it from the skin while avoiding smearing the xenobiotic or abrading the skin. Some contaminants may be chemically “inactivated” by applying another chemical, such as a 0.5% hypochlorite solution.

When performing decontamination, close attention should be paid to all exposed skin, particularly, the skin folds, axillae, genital area, and feet. Lukewarm water should be used with gentle water pressure to reduce the risk of hypothermia. Water should be applied systematically from head to toe while the patient’s airway is protected.

Exposed, symptomatic eyes should be continuously irrigated with water throughout the patient contact, including transport, if possible. Remember to check for and remove contact lenses.

Removal of internal contamination is often much more problematic. In some cases, specific medications may be administered to enhance elimination or inactivate the hazardous material. For instance, Prussian blue can trap radioactive cesium in the intestine so that it can be eliminated from the body in the stool rather than be reabsorbed.

Scene Triage.

Victim decontamination and movement from a scene requires an organized methodology for categorization of medical severity. The most common triage method used is the Simple Triage and Rapid Treatment system (START),⁴ although many others exist. This system follows a simple algorithm that allows for a color categorization based upon the victim’s respirations, perfusion, and mental status: immediate (red), delayed (yellow), walking wounded/minor (green), and deceased/expectant (black). Victims may be initially triaged in the contaminated zone and then re-triaged after decontamination.

OSHA and the NFPA have developed rules and guidelines, respectively, regarding hazardous materials incident response.^{24,31,32,33, and 34,40,45} OSHA rules are mandated as law and must be followed.^24,40,45 Meeting NFPA guidelines will ensure OSHA compliance.^{24,31,32,34,37,40}

The Superfund Amendments and Reauthorization Act of 1986 (SARA) required OSHA to develop and implement standards to protect employees responding to hazardous materials emergencies. This resulted in the Hazardous Waste Operations and Emergency Response standard, 29 CFR 1910.120, or HAZWOPER.⁴⁵

NFPA 471, Recommended Practice for Responding to Hazardous Materials Incidents, outlines the following tactical objectives: incident response planning, communication procedures, response levels, site safety, control zones, PPE, incident mitigation, decontamination, and medical monitoring.³²

NFPA 472, Standard on Professional Competence of Responders to Hazardous Materials Incidents, helps define the minimum skills, knowledge, and standards for training outlined in HAZWOPER for three types of responders.³³

Prehospital Hazardous Materials Emergency Response Team Composition, Organization, and Responsibilities

First Responder at the Awareness Level.

First responders at the awareness level could be first on the scene at an emergency incident involving hazardous material. They are expected to recognize the presence of hazardous materials, protect themselves, secure the area, and call for better trained personnel. They must take a safe position and keep other people from entering the area. They must recognize that the level of mitigation exceeds their training and call for a hazardous materials response team. Most basic curricula of emergency medical technicians include this level of first responder training.

First Responder at the Operational Level.

These individuals are trained in all competencies of the awareness level and are additionally trained to protect nearby persons, the environment, and exposed property from the effects of hazardous materials releases. Operational level certified individuals are expected to assume a defensive posture, control the release from a safe distance, and keep the hazardous material from spreading. Operational level individuals are trained to perform absorption of liquids, containment of the spill, vapor suppression, and vapor dispersion. They do not operate within the hot zone.

Hazardous Materials Technician.

Hazardous materials technicians respond to hazardous materials releases, or potential releases, for the purpose of controlling the release. They are trained in the use of chemical-resistant suits, air-monitoring equipment, mitigation techniques, and the interpretation of physical properties of hazardous materials. Technicians are capable of containing an incident, making safe entry into a hazardous environment, determining the appropriate course of action, victim rescue, and cleaning up or neutralizing the incident to return the property to a safe and usable status, if possible. These individuals are trained to operate within the hot zone to mitigate the incident. This certification level includes knowledge of hazardous material chemistry, air-monitoring equipment, tools used within the hot zone, and more.

Advanced Hazardous Materials Components

Advanced Hazardous Materials Providers.

Paramedics should be trained in the recognition of signs and symptoms caused by exposure to hazardous materials and the delivery of antidotal therapy to victims of ­hazardous materials poisonings.²⁴

The inclusion of such training into a hazardous materials response team is beneficial, not only for the needs of the public but also to protect hazardous materials technicians who make entry into hazardous atmospheres.²⁴ Ideally, hazardous materials technicians’ entry into hazardous atmospheres should not be performed until appropriately trained paramedics are on the scene with resuscitative equipment in place, including a drug box containing essential antidotes for specific hazardous materials.²⁴

Patient Care Responsibilities of the Prehospital Decontamination Team and the Hazardous Materials Entry Team.

Hazardous materials responders should identify the entry and exit areas by controlling points for the access corridor (decontamination corridor) from the hot zone, through the warm zone, to the cold zone (Fig. 131–1). This corridor should be upwind, uphill, and upstream from the hot zone, if possible. Hazardous materials technician entry team members should remove victims from the contaminated hot zone and deliver patients to the inner control point of the access (decontamination) corridor. Hazardous materials decontamination team members decontaminate patients in the decontamination (access) corridor of the contamination reduction (warm) zone.^{11,14,18,19,24,27,28,42}

The primary responsibility of the prehospital hazardous materials medical sector is the protection of the hazardous materials entry team ­personnel. This is accomplished by researching and recording clinically pertinent information about the hazardous material, remaining available on scene for medical treatment, and assessing individuals before entry into and on exit from a hazardous environment.²⁴ Documentation of each assessment should be recorded on a prepared form and compared with the exclusion criteria defined by NFPA 471.^24,32

In some systems, the hazardous materials entry team may include specialized providers who have the ability to provide lifesaving patient care within the hot zone. The ability to perform triage or cardiopulmonary resuscitation or to provide any medical care is greatly limited by the PPE being worn. Therefore, only immediately lifesaving procedures should be considered, such as intubation/ventilation or antidote administration using an autoinjector.

Patient Care Responsibilities of Emergency Medical Services Providers at Hazardous Materials Incidents.

EMS providers who are not part of the hazardous materials team should report to the incident staging area and await direction from the incident commander. They should approach the site from upwind, uphill, and upstream, if possible.

EMS providers should remain in the cold zone until properly protected hazardous materials incident responders arrive, decontaminate, and deliver patients to them for further triage and treatment. Then EMS providers should evaluate each patient, triage as appropriate, and move the patient to the appropriate casualty collection point or rapidly transport to the hospital as resources allow. Exposed victims who are initially asymptomatic should continue to be observed and reassessed for the delayed development of symptoms, and the EMS provider should be prepared to upgrade the triage category for the patient. All EMS systems should have protocols in place that direct operations at hazardous materials scenes. Ideally, the EMS response matrix for such events includes the response of an EMS physician or contact with online medical control who will coordinate appropriate care with the regional poison center, toxicologists, and hospitals.

Transportation of patients from the hazardous materials incident is ultimately under the control of the incident commander but is usually ­delegated to the prehospital hazardous materials medical sector and EMS providers. In general, no victim with skin contamination should be transported from the hazardous materials site without being properly decontaminated. Before transportation, EMS should notify the receiving hospital of the number of victims being transported and their toxicologic history, patient assessments, and treatment rendered.

Hospital Responsibilities for Hazardous Materials Victims

Ideally, the local or regional ED physicians and personnel will receive advanced notification about a hazardous materials incident before any victims arrive at the hospital. This notification to the hospital should occur as early in the event as possible to allow for maximum “ramp-up” time. The notification should include, if known, information regarding the event, hazardous materials involved, number and condition of casualties to be transported to the hospital, as well as information regarding the decontamination completed. Assistance of a poison center and a toxicologist is generally recommended.

Victims may leave an incident scene and subsequently present to a hospital. The hospital must have a preestablished protocol by which hospital response teams will decontaminate patients who arrive at the hospital if they have not been previously decontaminated or if field decontamination is believed to be insufficient.^{7,15,16,17,23,25,39,41,43,46,49,50} Hazardous materials patients who require skin decontamination should be denied entry to the ED until they are decontaminated by an appropriately trained and equipped hazardous materials response team. The emergency physician will determine when the patient is safe to enter the ED after carefully assessing the risks and benefits to the decontaminated patient, the other patients in the ED, and the ED health care personnel.

• Hazardous materials incident response is an integrated, interdisciplinary approach involving prehospital, hospital, poison center, and public health professionals.,

• Most patients at hazardous materials incidents are exposed through inhalation of a gas, a solid, or a liquid aerosol.

• Prehospital and hospital health care professionals must use appropriate PPE when caring for patients who have not been decontaminated.

• Decontamination is critical to alter absorption for patients and to prevent secondary contamination of downstream health care professionals and equipment.

• The general principles of toxicology apply regardless of whether a patient is at a hazardous materials incident in a prehospital or hospital setting. Although patient care resources vary among these treatment settings, the fundamental principles of patient care remain the same. All patients should receive a primary survey and resuscitation, emphasizing airway, breathing, and circulation.

Acknowledgment

Frank G. Walter, MD, contributed to this chapter in previous editions.

References