A hazardous material is defined as “a substance (either matter – solid, liquid, gas – or energy) that when released is capable of creating harm to people, the environment, and property…” and may mean little to most EMS providers and medical directors in their daily practice, despite that they are all around us. ¹ In addition to the recognition that hazardous materials are common components of our personal and occupational lives, it is important to consider the potential of a large-scale hazardous materials (HAZMAT) incident in any EMS system. Most EMS physicians are well versed in the occupational component of hazardous materials as it pertains to the Occupational Safety and Health Administration (OSHA) regulations that apply to the work environment but may not be fully prepared to respond in support of a hazardous materials incident operation and may not even be familiar with the principles laid out in 29 CFR 1910.120 (Hazardous Waste Operations and Emergency Response: HAZWOPER) or the availability of various publications on the topic provided by OSHA, NIOSH, FEMA, and the EPA. HAZMAT incidents occur in all areas affecting every community (Figure 72-1). This chapter will serve as a primer aimed at the EMS physician as a component of the response to a HAZMAT incident.

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  Discuss basic principles to the approach to a hazardous materials incident.

  
  
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  Discuss some specific concerns based on different types of hazards.

  
  
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  Describe PPE types and appropriate use of each.

  
  
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  Describe decontamination operations.

  
  
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  Describe the resources, equipment, and methods available for product/hazard identification.

  
  
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  Describe factors impeding medical operations in a hazardous materials environment.

Response to serious, large-scale, hazardous materials incidents is not a common operational event for the average EMS physician. Special training and experience are key components to a successful hazardous materials operation. Although most EMS physicians are not HAZMAT technicians there are still roles for a physician responding to these events (Box 72-1). Because of the importance of these physician-specific roles, those EMS physicians that are HAZMAT technicians should not become involved in the operation inside the hot or warm zones unless there is a specific and unusual medical intervention that can only be provided by the physician. The EMS physician is expected to serve as a medical content expert in all areas of prehospital care and toxicology is no exception. Serving as on-scene medical control for the sick and injured victims of a serious HAZMAT-associated incident allows providers to provide toxin-specific care without complicated radio communication and it also allows for rapid communication of special needs (eg, antidotes and secondary decontamination preparation) to the receiving hospital(s) and emergency management officials who can locate and potentially mobilize certain stockpiles. When medical and traumatic conditions coexist with a serious HAZMAT exposure, the EMS physician may also aid providers in prioritizing care goals (ie, rapid treatment and transport verses standard decontamination). In cases of mass casualty HAZMAT exposures, the physician may also aid in adjusting the triage values of patients who may normally be deemed immediate (red tag) in the standard triage (START and JumpSTART), but due to their exposure are unlikely to survive regardless of intervention. In some cases a nonbreathing expectant (black tag) individual may be deemed immediate (red tag) if the toxic exposure is known to be a that is easily reversed (eg, aerosolized fentanyl) (SALT triage). In addition to this role as a content expert, every operational activity that places a heavy physiological demand on the rescuers (like fire ground, tactical, and HAZMAT operations) should have some attention paid to provider rehabilitation (rehab). The EMS physician may need to serve as an advocate for, and play some part in, establishing a rehab station/revolution during the operation. In order to allow for success in these roles, the EMS physician must be involved in the preplanning for these types of events and have a working familiarity with key operational stakeholders. The EMS physician and/or medical director should be involved in disaster and operational response planning and actively seek out training and drill opportunities.

Serious exposures and/or large-scale incidences can occur in a number of circumstances and locations in a community (Box 72-2). Such exposures are significant as they may represent the ongoing presence of an environment that poses and immediate danger to life and health (IDLH). Agricultural and industrial environments are common places to encounter large amounts of hazardous materials in use and in storage. Farm and factory accidents can lead to large-scale exposure and the potential for numerous and/or very serious human exposures. Transportation of hazardous materials occurs through every community with roads, railroad tracks, pipelines, or waterways (Table 72-1, Figure 72-2). Large capacity containers are common in all forms of local, interstate, and international transportation of these substances. Other important exposures to consider are those encountered during fires (residential and commercial) and during EMS calls, especially where clandestine drug labs operate or bomb-making activity has been planned or performed. Acts of terrorism, both foreign and domestic, represent significant HAZMAT threats, especially when rescue and medical treatment goals may cause tunnel vision among emergency personnel. Another HAZMAT treat to the public and responders is the intentional creation of toxic gas or other dangerous materials for the purpose of suicide and EMS physicians should be well versed in these trends.

The Department of Transportation (DOT) has defined classes of hazardous materials in an effort to categorize like materials and establish general patterns of handling and hazard mitigation. The DOT defined nine categories depicted in Table 72-2. Another way to consider hazardous materials is by their general category describing the key type of hazard when exposed to humans: chemical, biological, radiological/nuclear, and explosive (CBRNE). Hazard risks from different classes or types of materials are also described under the DOT class as having one of more of five hazard risks. These are thermal, radioactive, asphyxiation, chemical, etiological, and mechanical (TRACEM). ² Thermal refers to heat damage (eg, burns). Radioactive refers to all radiological injuries (acute and chronic). Asphyxiation risk is due to a materials ability to cause displacement of oxygen, or the rendering of the lungs incapable of exchanging gases. Chemical risk refers to a materials activity when interacting with substances that make it react in a hazardous way, or to the reaction it has when in contact with humans (eg, creation of toxic fumes during a reaction, chemical burns). Etiological risk refers a substances potential to cause disease (eg, cancer). Mechanical risk is any associated mechanical force or injury applied to humans relative to the other properties of the substance (eg, shrapnel from the explosion of the container, blast wave from an explosion).

CHEMICAL

Gases (DOT Class 2) pose at times extreme danger due to their ability to rapidly expand if heated or otherwise improperly released. Flammable and combustible liquids (DOT Class 3) may cause significant heat release, or result in a boiling liquid expanding vapor explosion (BLEVE). Flammable and combustible solids (DOT Class 4) may pose significant risk due to their ability to burn in the correct conditions, and many of them are unstable in wet environments, like when sprayed with a hose or washed from a patient with wet decontamination techniques. Oxidizers (DOT Class 5) are also potentially exothermic in that they can cause rapid reactions in the presence of oxygen, or by removing it from the air. Toxins (DOT Class 6) can take many forms and can be very potent in concentrations found in industrial usage. Strict decontamination practices are required to avoid secondary contamination. Corrosives (DOT Class 8) are acids and bases and are very dangerous to skin, eyes, lungs, and may react violently when exposed to certain substances. Miscellaneous (DOT Class 9) can be any hazardous substance not meeting the other definitions. In many cases the substance is hazardous in certain situations during transport, due to temperature or its potential effects on drivers or pilots if they were exposed during operation of the vehicle.

Clandestine drug labs pose a unique, potentially occult, threat to rescuers and prehospital providers. The chemicals used in the “cooking” of methamphetamine, for example, present significant hazards, as do the by-products of the “cook” (Box 72-3). ³ Typically responders should be on the alert when a collection of chemicals, cleaners, or other industrial use materials are found in the kitchen or living spaces, especially when cooking equipment, scales, and industrial/chemistry glass implements are also noted. Low technology setups are also common and may be in the bathroom, closet, or even in a bag or the trunk of a car.

BIOLOGICAL

Biological hazardous material can include medical waste (DOT Class 6), laboratory waste (DOT Class 6), or even infectious agents (DOT Class 6). In the case of a planned act of violence these may be attached to a bomb or otherwise may have been weaponized for use in bioterrorism (Box 72-4). Infectious agents and bioterrorism are covered in Chapter 48.

RADIOLOGICAL/NUCLEAR (DOT CLASS 7)

Radiological and nuclear hazards are of constant concern for law enforcement, national security agencies, and emergency management organizations. EMS physicians must know the basics of response to radiological emergencies.

Radiation Types

The broad classification of radiation that affects our view of medical threat is that of nonionizing and ionizing. Ionizing radiation is biologically significant due to the fact that it has a high frequency and short wave length, and carries enough kinetic energy to liberate an electron and ionize the affected atom or molecule. Direct damage or indirect damage through the formation of free radicals leads to dysfunction in DNA and molecular machinery. Acute and long-term effects are related to the dysfunction that follows the exposure including cell killing, mutations, chromosomal aberrations, oncogenic transformation, and alteration of gene expression. Stochastic effects are accumulative and include risk of cancer, decline in microvasculature leading to radiation-induced soft tissue wound healing issues, and teratogenesis. Nonstochastic effects include burns, hair loss, cataract, hemopoietic syndrome, gastrointestinal syndrome, and central nervous system dysfunction.

Ionizing Radiation

There are different types of ionizing radiation to consider: α, β, γ, x-ray, and neutrons. α Particles are positively charged particles with a high linear energy transfer and a very short penetrance and are very dangerous if ingested. β Particles are high energy electrons emitted from a nucleus and vary in energy. β Particles are not as efficient as α particles at ionizing, but penetrate up to 2 to 3 m in air, but cannot penetrate deeper than the skin. γ Radiation is emitted from the nucleus and penetrates many meters through air and may require lead or concrete shielding. X-rays are emitted from outside the nucleus and are usually created by bombarding a target with electrons until target electrons change energy shells. They can also be emitted from a radioactive material and have similar penetrating effectiveness to that of γ radiation. Neutrons are uncharged particles that have deep penetration and are present inside nuclear reactors (Figure 72-3).

Units of Measure

The most basic way to measure radiation would be to consider exposure, which tells us only the ionization component and is typically relayed in roentgen or coulomb. Radiation risk to humans is usually discussed in terms of absorbed dose and equivalent dose. Absorbed dose is the absorption of radiation energy per unit mass of the absorber of ionizing radiation and the equivalent dose represents the biologic risk of damage from that dose. The units associated with absorbed dose are the Gray (Gy = 1J/kg) and the rad (rad = 100erg/g) and the units for equivalent dose (absorbed dose X radiation weighting factor) are rem and sievert (Sv = 100rem). The rad (radiation absorbed dose) is equal to 0.01J/kg. The rem (radiation equivalent in man) is equal to the biological damage expected from absorption of 0.01J/kg.

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  1Gy = 100rad

  
  
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  1mGy = 100mrad

  
  
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  1Sv = 100rem

  
  
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  1mSv = 100mrem

These units are extremely helpful and easily equate to controlled exposures in the medical setting (such as radiology or nuclear medicine) and in nuclear power facilities where excessive monitoring and safety programs have led to detailed understanding of the risks to humans. Unfortunately, in the HAZMAT response scenario, this is no likely to be the case and the EMS physician is more likely to be given information in the form of counts per minute (CPM) from radiological survey meters. This is the time for consultation of a health physics expert because there is not really a direct conversion to dose rate. Typically, the radiological survey meter (Geiger counter) displaying CPM is relaying the number of atoms in the radioactive material that are detected to have decayed in 1 minute based on a calibration to Cesium-137 (Cs-137) and therefore 120 CPM on the meter (for Cs-137) is about 1 µSv/h (microsievert per hour) or 0.001 mSv (0.1 mrem). The usual cutoff for detection of the presence of radiological contamination is >100 CPM. This means there is likely more than background radiation present. In order to estimate, the dose rate (dose per minute) is essential to consult with a health physics expert. If a health physics technologist is present and can estimate dose/minute, then this may be used to calculate estimated dose and in ALARA calculations for rescuers (http://www.radprocalculator.com/ALARA.aspx). It is important to note that rescuers with an estimated potential risk of receiving over 25,000 mrem should be involved in lifesaving activities and be made aware of the risks. They must be volunteers at this level of exposure. In addition, it is important to consider that the risk of ingested radioisotopes represents a much higher risk from internal exposure when compared to external exposure to radiation. This risk should be relayed to all rescuers and, as with all HAZMAT operations, no eating, drinking, or touching of the face or mucous membranes should occur in areas where primary or secondary contamination may be present.

Exposure and Contamination