Chapter 35 Medical support for hazardous materials response

Thomas Blackwell, Kenneth Brennan, Craig DeAtley, and Allen Yee

IntroductionThe potential for hazardous materials (hazmat) incidents is significant. More than 60,000 chemicals are produced annually in the United States. More than 4 billion tons of chemicals are transported yearly via surface, air, or water routes, with more than 500,000 shipments of hazardous materials made every day. In an attempt to define the magnitude of the nation’s hazmat incidents, the Agency for Toxic Substances Disease Registry (ATSDR) developed the Hazardous Substances Emergency Events Surveillance (HSEES) system in 1990. Fifteen state health departments participate in the reporting system. In these 15 states, the system has shown the following [1].

About 9,000 releases of hazardous substances occur annually, with 75% occurring at chemical facilities and 25% occurring during transportation.

Most transportation-related incidents occurred during ground transport (85%), and 26% occurred in residential areas.

Human error and equipment failure account for most releases.

The most common substances involved were inorganic substances (24%) followed by volatile organic compounds (20%).

More than 2,000 people are victims of hazardous materials releases in these states each year. Approximately 50% of these are transported to hospitals. Respiratory and eye irritation are the most common types of injury. Over a 4-year period, 132 deaths related to hazardous materials occurred.

More than 7,500 people required decontamination during hazmat events over a 4-year period in these states. Of these, 2643 were decontaminated at medical facilities.

Whether from household agents, industrial incidents, or acts of terrorism, EMS, fire, and law enforcement personnel face a variety of response issues related to hazardous materials.

Developing standard operating proceduresEvery organization that has the responsibility to respond to hazmat incidents should develop standard operating guidelines (SOGs) that delineate roles, responsibilities, and pertinent response procedures. Ideally, responding agencies should coordinate their plans with neighboring jurisdictions to ensure interoperability. SOGs should address when and how to implement personal protective equipment (PPE) use, medical decontamination of ill or injured victims, and technical and emergency decontamination of responders. Individual agency SOGs should be part of a community response plan that provides the foundation for the overall incident response. Of particular importance from a medical perspective is the need for clarity on which agency (or agencies) will be providing medical support in the various work locations (hot, warm, and cold

zones) and ensuring that they have the necessary protocols, equipment, and training to carry out their assignments successfully [2]. This level of planning requires that representatives from the various agencies meet on a regular basis to write, train, exercise, and revise the plan.

Once a plan is developed, training sessions and exercises should be conducted on a regular basis. All first responder agencies have multiple responsibilities that require ongoing training. Effective training is best conducted by expert personnel who create a rigorous training program for all aspects of response to these types of incidents. Individual agency training can provide important instruction on department SOGs. However, multiagency training conducted on a regular basis permits practice in the areas of unified command, integration of community resources, resource sharing, joint decision making, and information sharing. Effective training culminates with after-action discussions and reports, and revising plans, policies, and procedures.

Identifying potential threatsHazardous materials are found in homes, businesses, industries, and transportation corridors. A comprehensive hazard vulnerability analysis should be conducted to determine what significant risks exist in the local community.

The federal Superfund Amendments and Reauthorization Act became law in 1986. Title III of these SARA provisions is also known as the Emergency Planning and Community Right-to-Know Act (EPCRA). SARA Title III requires states to:

promote outreach for developing local emergency preparedness programs to respond to chemical releases

receive reports from the regulated community

organize, analyze, and disseminate the resulting information on hazardous chemicals to local governments and the public.

Specifically, this has required the establishment of state emergency response commissions and local emergency planning committees. The nationwide regulated community of manufacturers and non-manufacturers of hazardous chemicals must report concerning their emergency chemical releases; their Material Safety Data Sheets (MSDS); their facility hazardous chemical inventories (Tier I and Tier II reports); and their toxic chemical releases to the air, land, or water (Toxics Release Inventory). Because of this activity, businesses have reassessed their chemical inventories and their manufacturing processes. In addition, more businesses are working cooperatively with local governments to plan for and try to prevent accidental chemical releases.

Fire department preplans and fire marshal inspection of commercial buildings and transportation centers, along with law enforcement intelligence information on high-risk targets and clandestine drug laboratories, should be considered when identifying response risks.

Medical response planningAfter identification of potential risks, medical response procedures should be developed and published in conjunction with the department’s medical director, emergency management, local medical facilities, and other appropriate community experts such as poison centers. Protocols for specific classes of agents or individual threats should be written and include information on signs

and symptoms, personal protective measures required, need for decontamination, and treatment recommendations [3].

Written publications on various agents are available from the Federal Emergency Management Agency (FEMA), Environmental Protection Agency (EPA), Occupational Safety and Health Administration (OSHA), and National Institute for Occupational Safety and Health (NIOSH) as well as non-government publishers. In addition, the American Association for Poison Control Centers offers 24-hour planning and response information assistance and can be reached at 1-800-222-1212.

The Chemical Transportation Emergency Center (CHEM-TREC), maintained by the Chemical Manufacturers Association, is another 24-hour resource for obtaining planning information and emergency response information, particularly for chemical releases, and can be reached at 1-800-424-9300. The Agency for Toxic Substances and Disease Registry (ATSDR) offers a 24-hour emergency number for health-related support in hazardous materials emergencies, and can be reached at 1-800-232-4636. Hotline services operated by government agencies such as the EPA and US Army Soldier and Biological Chemical Command (SBCCOM) can be contacted for assistance. There are several government web addresses such as those listed below that provide useful planning and response information.

www.epa.gov/ceppo/cameo  (computer-aided management of emergency operations) www.toxnet.nlm.nih.gov  (chemical information) www.wiser.nlm.nih.gov  (chemical information) www.bt.cdc.gov  (CBRNE information) www.remm.nlm.gov  (radiological information)

Personal protective equipmentAfter the events of September 11, 2001 and the anthrax attacks in 2001, increasing numbers of agencies have made various levels of PPE available to their personnel. Regardless of the user’s profession, the correct type of PPE must be used for its intended application. The PPE must be appropriately donned and doffed. Understanding the operational limitations of wearing PPE such as limited dexterity, reduced hearing, and muffled voice is best experienced and surmounted through frequent training.

Levels of protection for work involving hazardous materialsFour levels of protection have been defined for work involving hazardous chemicals. Although these levels originally were intended for work at hazardous waste disposal sites, they have been adopted widely in other situations, such as rescue work.

Level A is the highest level of protection (Figure 35.1). It is usually only worn by hazmat personnel and others working in areas of very high concentrations of toxic agents. A Level A ensemble consists of a fully encapsulating chemical-resistant suit, positive-pressure self-contained breathing apparatus (SCBA), double layers of chemical-resistant gloves, and chemical-resistant boots. The Level A ensemble will protect against vapor and splash threats. Most hazmat workers who enter the hot zone require Level A protection. This is very expensive, bulky, and requires specialized training in its use. The typical Level A hazmat suit costs several thousand dollars and must be properly cleaned between uses. Manual dexterity is poor and the suits retain

heat. With the physiological stressors and the self-contained air supply, Level A ensembles are limited in the amount of time that they can be worn.

Figure 35.1 Level A ensemble.Level B is used when full respiratory protection still is required but dangers to the skin are less. It consists of SCBA and a chemical-resistant suit with resistant gloves and boots (Figure 35.2). There is less vapor protection in a Level B ensemble.

Figure 35.2 Level B ensemble.

Level C is required when air concentrations are expected to be much lower and less likelihood of skin exposure exists. It consists of a full-face air purification device and a non-encapsulating chemical resistant suit with gloves and boots (Figure 35.3). Hazmat teams usually use Level B or C PPE when performing decontamination. This takes place away from the hot zone and when the amount of chemical present on a patient is significantly less than what exists in the hot zone. Also, quantities of chemicals that might present physical hazards, such as explosions, should not be present on a patient.

Level D protection is used only when no danger of chemical exposure exists. It consists of standard work clothes and no respiratory protection. Structural firefighting clothing protects against extremes of firefighting, especially heat and steam. This attire is most suitable for firefighters and includes full protective clothing (turnout coat, hood, and bunker pants), SCBA, helmet, gloves, and boots. Despite the respiratory protection provided by SCBA, limited chemical protection is provided by structural firefighting clothing, and it is considered level D PPE.

Available types of respiratory protectionSelf-contained breathing apparatus

Self-contained breathing apparatus provides breathable air in an immediate danger to life and health (IDLH) atmosphere. The term self-contained means that the breathing set is not dependent on a remote supply (e.g. through a long hose). An SCBA typically has three main components: a high-pressure tank, a pressure regulator, and an inhalation connection (mouthpiece, mouth mask or face mask).

Self-contained breathing apparatus may fall into two different categories: open circuit and closed circuit. The closed-circuit type filters, supplements, and recirculates exhaled gas. It is used when a longer-duration supply of breathing gas is needed, such as in mine rescue and in long tunnels, and going through passages too narrow for a big open-circuit air cylinder.

Open-circuit SCBA are more common. The apparatus is filled with filtered, compressed air, rather than pure oxygen. Typical open-circuit systems have two regulators – a first stage to reduce the pressure of air to allow it to be carried to the mask, and a second stage to reduce it even further to a level just above standard atmospheric pressure. This air is then fed to the mask via either a demand valve (activating only on inhalation) or a continuous positive pressure valve (providing constant airflow to the mask).

Supplied-air respirators (SARs)

Supplied-air respirators differ from SCBA in that the air is supplied through a line connected to a source away from the contaminated area. SARs are available in both positive- and negative-pressure models. However, only positive-pressure SARs are recommended for use at hazmat incidents. One major advantage the SAR has over SCBAs is that it allows an individual to work for a longer period. In addition, SARs are less bulky than SCBAs. By necessity, however, a worker must retrace his steps to stay connected to the SAR, and therefore cannot leave the contaminated work area by a different exit. SARs also require the air source to be in close proximity (within 300 feet) to the work area. In addition, personnel using an SAR should carry an immediately operable emergency escape supply of air, usually in the form of a small, compressed air cylinder, for use in case of an emergency.Cartridge respirators and supplied air respirators

Air-purifying cartridge respirators function by allowing the wearer to inhale air through a canister filled with a special sorbent material that binds chemical vapors. Cartridge respirators are inexpensive, portable, and easy to use and store. However, drawbacks to their general use exist. The type of cartridge used must match the chemical vapor in question. Different cartridges must be used to protect from organic vapors, acid gases, chlorine, ammonia, and methylamine. The sorbent materials also have a breakthrough phenomenon, in which chemicals elude off the sorbent after a period of use and then expose the user. Multisorbent cartridges are available that do not require matching with the vapor in question. In general, these have a shorter breakthrough period. These factors limit cartridge respirators to short-term use and to low concentrations of chemicals in the air. This is the situation that exists when patients require decontamination.

Cartridge respirators depend on an airtight seal against the face. They require a good fit and cannot be used with facial hair. A moderate amount of work is involved when inhaling across the pressure resistance of the cartridge. All of this requires that any individual using this type of respirator be fitted properly and trained in its use. Cartridge respirators are very versatile for short-term use. They require adequate training of all personnel who may be expected to use them and require someone available at all times to decide which type of cartridge to use. Cartridge respirators are ideal for performing decontamination outside the ED.

To overcome many of the problems with air-purifying cartridge respirators, battery-operated versions were developed. These use a battery-operated pump to draw air across the sorbent cartridge and pump it into a hood that surrounds the user's head. They do not require an airtight fit and can be used with facial hair. They do not require the user to work to draw air across the cartridge and, thus, are much cooler and less anxiety provoking. They also require less individual training. They still depend upon the cartridge to remove the vapor in question; thus, the cartridge must match the vapor. The time of use must be limited because of both chemical breakthrough in the cartridge and battery life. Since a clear shield surrounds the face, they provide better eye contact with the victims.

Accompanying accessories and attachmentsIn addition to the PPE described above, a number of accessories and attachments may be worn by public safety personnel including cooling and ventilation devices, flash garments, head protection, Nomex suits, and splash aprons.

To address body heat concerns, cooling and ventilation devices can be worn under the PPE and against the body. Because of safety and effectiveness concerns, the use of these devices is not widespread.

Most chemical protective suits are not flame resistant and should not be worn in situations where there is a risk of fire. Chemical protective suits can be worn with a flash overgarment. The overgarment only provides limited protection against a flash fire.

Helmets can be worn when personnel are operating in situations with overhead dangers from pipes, tree limbs, and similar dangers. These products can be added to PPE to provide additional protection during operations.

Implications of PPE usePhysical Limitations

Personal protective equipment ensembles have limitations for the user. A primary limitation is the bulkiness of the suit. SCBA is heavy, especially when the user is getting fatigued. In addition, it can limit ingress and egress through tight spaces. Air-tank time limitations must be strictly adhered to so that the user does not run out of air. Chemical protective gloves can limit dexterity and tactile feedback. These limitations make traditional medical interventions such as IV access almost impossible while wearing a Level A ensemble and medical care may be limited to basic airway interventions, major hemorrhage control (tourniquets), and autoinjector antidotes.

Communications

Standard radio use can be problematic. SCBA and respirators limit the volume and understandability of the user’s voice. Personnel can use microphones worn around the neck to amplify voice box vibrations. SCBA and respirator masks can be modified to provide voice amplification so the user’s voice can be better heard during conversation and when giving verbal instructions to the public.Health risks

One of the key health risks associated with wearing any type of PPE is heat stress brought on by additional clothing, weight, and physical activity. Heat emergencies such as dehydration, heat cramps, and heatstroke can be mitigated by allowing only properly trained persons in good health and physical condition to wear PPE [2,4–7]. Pre- and postentry monitoring are important steps to providing situational health information on each responder. Proper hydration with electrolyte drinks and water along with good nutrition are also vital to limiting health risks.

Other health risks include injuries from falls due to limited vision while wearing PPE. Hearing can be impaired when working around noisy equipment and is further affected by wearing protective ear muffs or plugs. Cold emergencies such as hypothermia or frostbite can occur if insufficient underclothing is worn during winter months or when working around cryogenic materials.

Responding to hazardous materialsAssess the situation

Initial arriving units must consider the possibility that an incident involves hazardous materials [8–10]. Adhering to the old adage “every call can be a hazardous material call” has practical importance. When responding to a reported hazmat event, personnel should attempt to approach the incident from an uphill and upwind direction. This provides protection if the agent is being actively released into the environment. Providers should not get any closer to the potential danger than is necessary.

Determine threat risk and initial required actionsIdentification of the actual or likely agents involved allows determination of the threat risk and the initial required actions. Certain information should be ascertained on every event.

Life safety

o Risks to people and responders

o Resources needed for immediate rescue

o PPE requirements

Incident stabilization

o Presence of fire, spill, or leak

o Resources needed for containment

o Effects of terrain

o Population evacuation

Property conservation

o Risks to property and the environment

The incident commander should communicate the strategies and tactics to deal with the incident to all responding personnel.

Establish a perimeterAn inner and outer perimeter should be established rapidly based on the initial information. Starting with a large perimeter is preferable, as reducing the size of a perimeter is easier than expanding it. The US Department of Transportation’s Emergency Response Guide (ERG) can be a useful tool to determine the size of the perimeter. Command personnel should determine whether personnel on the perimeter require PPE. While establishing the perimeters, ingress and egress corridors should be set up for response personnel.

Establish incident commandThe first arriving unit should establish single-agency incident command and transition to unified command as outside agencies respond to assist. The command post area should be cleared of secondary threat risks prior to establishment. Additional functions of the incident command system (ICS) should be established as needed, but high priority should be given to the staging sector to avoid disorganized arrival of responding personnel.

Product identification

Identification of the product or products should occur as soon as possible. Placard or label information can be looked up in the ERG or other similarly designed reference texts including computer programs to identify the agent. Contacting CHEMTREC or the Poison Center can also assist with product identification.

The arrival of hazmat-trained personnel with sophisticated monitoring and detection equipment may help to accelerate the identification of an unidentified product. Recognition and assessment of patient signs and symptoms may be the only initial information available to identify the class of hazard or agent. Product identity information should be shared among all response personnel and area health care facilities that may receive patients by EMS or self-directed transport from the scene. Treatment plans can be more completely detailed once the product identity is known, particularly regarding the need for specific antidotes.

EvacuationsThe incident commander will determine whether evacuations will be required. If an evacuation is necessary, then a plan must be quickly devised and specific assignments given to response personnel. Depending on the situation and resource availability, EMS personnel may be assigned to an evacuation center to assist with medical evaluation or to other on-site responsibilities.

Monitoring and detection devicesVarious forms of chemical agent detectors are available for monitoring initial contamination and screening contaminated patients. Devices may also be used to monitor residual contamination after decontamination of victims and equipment. Technologies used in detectors include infrared radiation (photo-acoustic infrared spectroscopy and filter-based infra-red spectroscopy), ion mobility detection (spectroscopy), flame spectrophotometry (photometric detection), and enzymes (colorimetric tubes and detection tickets). Monitors may be handheld for personnel and equipment detection or stand-alone for area detection. A more basic method when screening for nerve and blister agents includes the use of detection paper, which uses dyes. Corrosive agents can be detected by the use of pH indicators. While detection paper is inexpensive and can be used to distinguish between different types of chemical agents, other substances, such as fats and oils, dissolve the pigments and cause false-positive results. The military currently uses the M8 and M9 chemical detector paper, which uses an enzyme method to detect nerve and blister agents.

At an incident involving radioactive materials, a radiation survey meter is used to determine the type of radiation present (alpha, beta, gamma) and its level. Use meter readings and radiation safety guidelines to delineate safe and restricted zones. In addition to radiation survey meters, personal dosimeters can be used to estimate an individual’s dose of radiation.

DecontaminationGeneral principlesMost activities that involve handling hazardous materials or wastes will result in some form of contact with the hazardous materials. Contamination is described as the presence of an unwanted material or substance. Personnel may become contaminated in a number of ways including:

contacting vapors, mists, or particulates in the air

being splashed by materials while sampling or opening containers; spray from releases

walking, sitting, or kneeling on contaminated surfaces

handling contaminated instruments or equipment.

Fortunately, protective clothing and respirators prevent the wearer from being exposed to contaminants. Good work practices will reduce contamination on protective clothing, instruments, and equipment. Even with PPE and good work practices, hazardous substances can stick to personnel and equipment. Personnel will always have the potential to contaminate the equipment and clothing during site operations. If hazardous substances are not removed from workers and equipment exiting the hot zone, they could be spread to clean areas.

The principles of decontamination are based upon an understanding of the two types of contamination. Primary contamination is the result of direct transfer of contamination from the source to a person or object. Secondary contamination is the transfer of contamination from a person or object to another person or object.

Decontamination is the process of removing or deactivating harmful contaminants from surfaces of persons or objects by dilution and physical measures. This removal reduces exposure, regardless of the agent’s physical phase (solid, liquid, or gas).

Methods of decontaminationThere are many methods that can be used for decontamination. The method selected must be effective for the situation. The removal technique is based on:

type, nature, and concentration of the contaminant involved

the amount of contamination

the levels of protection required

the type of protective clothing worn

the type of contamination (surface or permeated)

the characteristics of the surface or equipment that will be decontaminated.

Physical removal techniquesPhysical removal is effective for surface (adsorbed) contamination. Several methods may be employed. It is important to remember that some physical removal techniques may lead to air-borne contamination.

Brushing. Loose particulate material can simply be brushed off protective clothing and equipment. Brushing should be performed starting at the top and sweeping downward. Using damp wipes may be appropriate to lower the potential of air-borne dusts.

Scraping. Scrapers are effective in removing highly viscous liquids and solids from surfaces of boots, gloves, and equipment.

Vacuuming. Vacuums equipped with HEPA filters may be used to remove and contain particulate matter from surfaces. Vacuums may also be employed for liquid spills. Special precautions for flammable liquids must be observed.

Washing and rinsing. Washing and rinsing will remove surface and some permeated contamination. Pressure washers can be used to remove many contaminants from structures (not people). All water removal techniques require a plan for the collection and disposal of the waste water generated.

Heat and steam cleaning. In some limited circumstances, heat can be used to drive off volatile contaminants. Heat is most effectively used with equipment decontamination. Steam jets can be used to liquefy viscous petroleum products and allow removal from equipment.

Chemical removal techniquesChemical removal techniques change either the contaminant’s form or properties. This makes the contaminant less hazardous or easier to remove.

Absorption. Using pads or absorbent towels to wipe the chemical off an area.

Adsorption. The use of activated charcoal or other adsorbents can minimize the effects of chemicals. Adsorption is a process where the product is chemically adhered to the adsorbent material. This is not to be confused with absorption in which the product is simply “soaked up.”

Degradation. The use of one chemical to destroy the hazards of another chemical.

Dilution. Using water or a solvent “dilutes” and lessens the hazards of the chemical.

Evaporation. Some products will simply evaporate completely over a given period of time. Care should be taken regarding any residue that is left.

Isolation and disposal. Many times the simplest method is to carefully remove the contaminated articles, bag them, and throw them out as hazardous waste. This is the idea behind disposable PPE.

Dissolving contaminants. Chemical removal of surface contaminants can be accomplished by dissolving them in a solvent. The solvent must be chemically compatible with the equipment being cleaned. In addition, care must be taken in selecting, using, and disposing of any organic solvents that may be flammable or potentially toxic. Usually surfactants are used rather than solvents.

Surfactants. A surfactant enhances physical cleaning methods by reducing adhesion forces between contaminants and the surface being cleaned. Household detergents are among the most common surfactants. Some detergents can be used in conjunction with solvents to improve the dissolving and dispersal of contaminants into the solvent.

Neutralization. Although rarely done on PPE, neutralization can be used to render acids and bases non-corrosive. Acids can be neutralized with lime, limestone, or sodium bicarbonate. Bases can be neutralized with weak acids. These chemical reactions may result in a non-hazardous by-product that can be disposed of easily. Neutralization reactions give off heat and must be done slowly in a controlled manner by trained and experienced personnel.

Chemical oxidation. Some chemicals, like cyanide, are easy to break down with oxidizing materials. Technically qualified personnel, who understand the reaction path, should supervise these activities.

Solidification. Solidifying liquid or gel contaminants can enhance their removal by physical methods. Generally, solidification is used to remove moisture and bind the chemical so it will not be released from the solid.

Disinfection/sterilization. Chemical disinfectants are a practical means of inactivating infectious agents. Unfortunately, standard sterilization techniques are generally impractical for large equipment and for PPE.

Wet versus dry decontaminationWet processes may be used when the PPE worn has sealed seams. Wet decon on sewn seam suits will transport contamination into the suit and potentially contact the skin. In general, wet decon should be reserved for situations where:

sealed seam garments are worn

the chemical presents a severe skin corrosion hazard

casual contact by the decon crew may be hazardous to them

run-off can be contained.

Dry decon involves the careful and controlled removal of garments and can be a very effective technique. This method is preferred for disposable garments when chemicals are not pervasive and have low skin contact hazard.

Decontamination implementationThe initial technical decontamination plan should be based on a worst-case scenario. Decontamination procedures must be developed, communicated to personnel, and implemented before any personnel or equipment enters areas on site where the potential for exposure to hazardous substances exists (i.e. the hot zone). Technical decontamination processes can be determined by using the product’s MSDS or other chemical reference material. The hazmat technician should be able to assist with basic chemical information as to which decontamination process would be most effective.

Decontamination procedures must provide an organized process by which levels of contamination are systematically reduced. The process must include:

standard operating procedures to minimize personnel contact with hazardous substances or with equipment that has contacted hazardous substances

decontamination of all personnel exiting contaminated areas

monitoring of all decontamination procedures by the safety officer to determine their effectiveness. When such procedures are found to be ineffective, appropriate steps shall be taken to correct any deficiencies.

Personal protective equipment in decontamination area

The decon corridor can be set up without wearing any PPE due to the fact that the warm zone is not contaminated until the decontamination process begins. The level of PPE worn by decon team members is related to what the entry team is wearing. Decon team members coming into contact with the contaminated entry team members should be in a level of PPE no more than one level below the entry team.

Decontamination locationDecontamination must be performed in geographical areas that will minimize the potential for exposure of personnel and the environment. Multiple locations can be used for performing decontamination. Indoor locations such as gymnasiums, swimming pools, and warehouses afford privacy, the potential for heated water, and environmental control. Disadvantages of indoor locations include lack of available space, air-borne concentration of the agent, limited ingress/egress and equipment access. Outdoor locations provide ample space for equipment and personnel, air-borne dilution, and shower run-off into a storm sewer. Disadvantages of outdoor locations include the potential lack of privacy, weather dependency, and potential access only to cold water. The size of the decontamination area will depend on the number of stations in the decon procedure, overall dimensions of work-control zones, and the amount of space available at the site. Whenever possible, it should be a straight path. All decontamination must be completed prior to any personnel or equipment entering the cold zone. The decontamination area should be conspicuously marked with signs for entry and exit (Figure 35.4).

Rapid mass decontaminationRapid mass decontamination occurs immediately upon arrival to an incident where multiple patients are symptomatic. It is performed by incident responders trained to the awareness or operations level. Rapid mass decon can be achieved by “wetting down” patients as they walk past a fire engine. Decontamination solutions and systematic washing are not necessary at first. Dry decontamination should be considered as an alternative.

Mass decontaminationMass decontamination is considered an extension of the rapid mass decon operation. As a decontamination operation develops, additional arriving resources provide the incident commander with the ability to control patients and direct their movement through decon to triage and treatment. The complexity of a decon operation also will grow from a single handline or clothing removal area to a well-coordinated decontamination corridor with multiple handlines and containment areas. Water pressure should not exceed 50–60 psi and the exposure duration should be approximately 3 minutes. Additional considerations should be made to accommodate separate corridors for males and females as well as ambulatory and non-ambulatory victims. When non-ambulatory patients are carried on stretchers through such flooded corridors, special attention should be directed to airway protection as supine patients on their backs are at risk of aspiration or near-drowning when large volumes of water are encountered in this position. Multiple divisions and groups will develop and the patients who have not left the scene already

will be looking for direction. Assigning a decontamination officer will provide patients and firefighters with clear direction in a chaotic environment.

Medical decontaminationThe decontamination of a patient is performed in a series of steps beginning with clearing the victims out of the hot zone as soon as possible and initiating the triage process in a safe environment. Triage for decontamination should be based on the victim’s proximity to the release site: first those exposed to vapors or aerosols, followed by those exposed to liquid forms, and then those with severe complaints or injuries. It should be expected that some persons who were not in the immediate danger area nor are suffering any apparent ill effects will still seek medical assistance out of fear. Clothing removal prior to showering is recommended for chemical decontamination and may remove 80% of the secondary risk [3,8–10]. This may require cutting clothes off non-ambulatory patients to minimize cross-contamination. Cutting down the center of the victim’s clothing and rolling the clothing toward the sides is a generally accepted practice for minimizing contamination spread; removing contaminated clothing overhead can increase the harm risk. Removed clothing and valuables should be “bagged and tagged” and placed in a secure location pending an eventual decision as to whether the belongings can be returned to the victims with specific cleaning instructions. If a criminal act or terrorist attack is suspected, all clothing and valuables should be considered evidence. Law enforcement personnel presence in the decontamination sector is desirable to protect the chain of evidence.

If mass casualties are involved, an initial or “gross decon” shower before clothing removal, especially for liquid exposures, will help to reduce toxic exposures. Patients should then proceed through a standard patient decontamination process as soon as additional resources are organized. Water used for decontamination should be high volume, low pressure, and tepid if possible to avoid shivering or skin vessel vasodilation. Ambulatory patients will often be able to perform decontamination themselves but need to be directed to wash themselves in a systematic head-to-toe manner. Non-ambulatory patients will require staff assistance. Non-ambulatory patients should be decontaminated in the following order: first airway, then open wounds, and then front and back from head to toe. The rinse-wash-rinse cycle should be continued until desired cleanliness is achieved. The process usually requires 3–5 minutes for non-viscous substances and 5–8 minutes for viscous or unknown agents. Only radiation detectors are currently available to screen for cleaning effectiveness in many communities. More complex meters and monitors may not be available at the decon site during large-scale events. Thus, in most cases “clean as clean can be” is usually determined by the clinical judgment of the decon team members.

Decontamination protocols should address the possibility of pediatric patients requiring decon in addition to other patients with special needs, such as a patient with colostomies, deaf or hard-of-hearing patients, and poorly ambulatory patients using walkers or wheelchairs.

A towel and redress supplies (clothing and foot covers) should be available for all victims once the decontamination is complete.

The issue of water-reactive chemicals causing exothermic reactions during water-based decontamination is usually not an important consideration. Limited medical interventions may be required before the decontamination procedures commence, depending on the medical condition of the patient. Life-saving interventions implemented prior to or while awaiting decontamination

should be limited to airway support, hemorrhage control, and administration of appropriate antidotes.

Once decontamination is complete, the patients should proceed to the cold zone/support zone where they should be medically assessed and provided with medical treatment. Transport to the hospital may require personnel in an appropriate level of PPE. The receiving facility should be given an early notification of the incident along with periodic situational updates, including the identified agent or agents and type of decontamination being implemented.

Additional considerationsSpecific statements regarding the numbers of ambulatory and non-ambulatory patients that can be decontaminated are actually estimated numbers. No models exist for gas, liquid, or vapor contamination that are consistent, reproducible, and measurable. Evidence to support what constitutes complete or even adequate decontamination does not exist. With multiple victims and responders, decontamination may be accomplished on a large number but probably not all victims before some begin to leave the scene. While serving the greatest number of victims reduces morbidity and mortality due to the likely agents and degrees of exposure, this fact reinforces the importance of first responders advising hospitals early and often regarding the actions taken at the scene to minimize the relocation of the disaster.

It is often difficult to ascertain when to rotate staff performing decontamination procedures, especially when in Level B or C personal protection. Fatigue and heat exhaustion are risk factors, and it is sometimes unclear when staff need to be rotated out for rehabilitation. Thus, the safety officer and hazmat branch director must take into account temperature, humidity, and rigor of the activities being undertaken when setting up a rotation schedule [11].

Technical decontaminationTechnical decon will be set up by the hazmat team to safely remove contamination from the PPE worn by the entry teams. They will also decon their tools and equipment in this area. Technical decontamination can be set up and staffed by operations-level responders.

To prevent the spread of contamination, methods to reduce and remove contamination must be developed. These methods and procedures must be established before anyone enters the hot zone. The best way to eliminate problems with decontamination is to prevent or minimize contamination from occurring in the first place.

Once decontamination procedures have been established, all personnel who may require decontamination must be given precise instructions. The safety officer should regularly inspect the process to determine its effectiveness. The time it takes for decontamination must also be ascertained, since personnel wearing SCBAs must exit their work area with sufficient air to walk through the decontamination process. In general, there are two types of processes: wet and dry.

Personnel decontamination proceduresThe decontamination process should consist of a series of procedures performed in a specific sequence. Outer, more heavily contaminated items (e.g. boots and gloves) should be decontaminated and/or removed first, followed by the decontamination and removal of inner, less contaminated items of clothing. Each procedure should be performed at a separate station in order to prevent cross-contamination. Stations should be separated physically and should be arranged in order of decreasing contamination, preferably in a straight line.

Decontamination of decon equipment proceduresDecontamination of equipment, materials, and supplies is generally selected based on availability, and ease of decontaminating the piece of equipment versus disposability. Most equipment and supplies can be easily procured. For instance, soft-bristle scrub brushes or long-handle brushes are used to remove contaminants. Water in buckets or garden sprayers is used for rinsing. Large galvanized washtubs or stock tanks can hold wash and rinse solutions. A child’s wading pool can also be used for employees to stand in when being decontaminated. Large plastic garbage cans or other similar containers lined with plastic bags are convenient for storing contaminated clothing and equipment. Contaminated liquids can be temporarily stored in metal or plastic cans or drums. Other gear includes paper or cloth towels for drying protective clothing and equipment.

Emergency decontaminationEmergency decon may be required when a responder dressed in PPE has a suit breach or suddenly becomes ill or injured. Hazmat teams are required to establish a means of emergency decontamination prior to entry unless there is an imminent rescue. Emergency decontamination can be handled easily by an engine company, but must be assigned early. Emergency decon should also be used for any first responders who are exposed to an undesired agent. In this situation the responders should be promptly transported to the technical decon corridor where they are washed quickly with soap and water before being taken to the warm zone–cold zone border, where they are removed from their suits and receive required medical attention. If the technical decon area is not immediately accessible, then this emergency decon can be accomplished by using copious amounts of water from a nearby hose, shower, or pool.

Medical monitoring of response personnelMedical providers including EMS physicians may play a critical role in maintaining the health and safety of response personnel on the scene of a hazardous material emergency. OSHA Standard 29 CFR 1910.120 mandates medical monitoring or surveillance for all hazmat team members. Many people may think that this is merely the act of taking a pulse and blood pressure before the entry team enters the hot zone. While this part is true, the medical monitoring of a hazmat team is actually an in-depth, four-part process consisting of a baseline physical exam before the member joins the team, annual physical exams while the member is part of the team, an exit physical when the member leaves the team, and any exposure-specific physicals or follow-up exams that are deemed necessary. These four steps are in addition to the medical monitoring done at the incident scene.

The baseline physical includes a detailed, comprehensive health history that includes any previous chemical exposure. A complete physical examination is also administered that includes vision, hearing, and laboratory blood work. A comprehensive metabolic profile, urine analysis, heavy metal testing, and complete blood counts should be included in the blood work. These tests are used to obtain baseline numbers for future reference should the member undergo a chemical exposure. Electrocardiograms and chest x-rays should also be taken.

The annual physical is a repeat of the initial baseline physical. It is used to update the medical history of the member as well as to verify the member's fitness for duty.

A key role of medical personnel is the monitoring of personnel during an incident. The NFPA 1584, Standard on the Rehabilitation Process for Members during Emergency Operations and Training Exercises, provides fire and EMS personnel with guidance on how to establish and operate a rehabilitation program [5]. It should be noted that this standard is based on consensus more than on evidence.Critical components addressed in the guidance are relief from climatic conditions, rest and recovery, cooling or rewarming, rehydration, calorie and electrolyte replacement, medical monitoring and treatment, member accountability, and release from rehab. A monitoring station staffed with medical personnel familiar with their roles and reporting to a rehab officer should be established in a safe and secure location (Figure 35.5). Chairs and cots should be available along with access to medical equipment and light healthy refreshments and fluids.

Figure 35.5 Picture of Medical Support Unit.Source: Chesterfield Fire and EMS. Reproduced with permission.Medical monitoring activity includes conducting pre- and postentry evaluation of personnel wearing PPE. Each individual should have an assessment consistent with the agency’s SOG. Traditional examination elements include pulse, blood pressure, respiration, pulse oximetry, and body weight. Heat-related injuries are one of the biggest concerns that hazmat members face during entry into the hot zone. This is especially true when dealing with longer incidents or incidents where higher temperatures are involved. Brief information on current medical

conditions and medications should also be sought and recorded along with the other data on a medical record for each responder, which then becomes part of his/her department medical record.

Postevent, an exposure-specific physical can be given whenever a member is exposed to a chemical, whether symptoms are present or not. This includes a routine physical examination and laboratory tests geared toward the specific chemical involved in the exposure. The member also receives an exit physical when his or her assignment on the hazmat team comes to an end. This is also a repeat of the initial baseline physical and serves as an endpoint in terms of monitoring the member for possible chemical exposure. It helps to determine if later medical claims are related to his or her service on the hazmat team.

ConclusionWorking on an incident involving hazardous materials involves significant challenges and health threats to public safety personnel. A critical component of the response is medical support for personnel and the incident. The importance of having properly equipped and trained medical personnel conducting medical surveillance and managing on-scene emergencies involving response personnel or injured civilians has been reinforced by real-world events. Ensuring that the medical requirements of these types of incidents are met requires that the roles and responsibilities of personnel providing medical support be defined along with response SOGs. These SOGs should address PPE, medical monitoring practices, medical and technical decontamination, medical support, and treatment procedures.

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