Overview Questions

In beginning to explore this module on emergency preparedness as it relates to chemical incidents, please take a moment to consider the following questions:

  • What roles or tasks might you be required to assume if your facility were involved in responding to an emergency involving hazardous chemicals?
  • How familiar are you with your institution’s emergency response plan for ensuring the safety of hospital staff, patients, and facilities?
  • What is the clinical picture of chemical “warfare” agent exposure? How are chemical exposures treated?

Please keep these questions in mind as you read through this module.

About This Module:

This module is one of six intended to provide you with a basic awareness of the major emergency preparedness issues that you, as a hospital clinician, need to be familiar with. This module focuses on chemical incidents, providing an overview of key issues and highlighting some of the ways your expertise may be called upon during a chemical emergency.

Before taking this module, we recommend that you first complete Module 1: Emergency Preparedness: The Basics. That module provides detailed information on the context in which you and your facility will be operating in any kind of mass casualty scenario. In Module 1, you will learn about the Hospital Emergency Incident Command System (HEICS), your potential role in an emergency, protocols you will be expected to follow in an emergency, and other core information that sets the stage for the other five modules, including this one.



Onset of the Emergency

It’s the Sunday afternoon of President’s Day weekend. At three o’clock, hundreds of shoppers at a large Westchester mall begin experiencing eye pain, tearing, coughing, gagging, convulsing, and fainting. Minutes later, shoppers at Macy’s on 34th Street in Manhattan begin experiencing similar symptoms. By 3:30, people in Penn Station begin exhibiting symptoms as well. Shortly thereafter, television news reports show first responders in protective gear arriving at the various locations. These reports reveal that a terrorist group has claimed responsibility for an orchestrated release of chemical agents using remote-control devices attached to hundreds of hidden canisters in the affected locations.

Scenario Question 1:
As a hospital-based health-care professional residing in Westchester, you happen to be driving near the mall when you hear the news on the radio. You want to help, so you proceed to the mall. When you get there, the scene is chaotic. Terrified people are running from the site of the disaster and those in cars are ignoring police directions on traffic flow. Which of the following is your most appropriate response?
A. Make your way over to the first responders by the decontamination trailer, give them your credentials, and request protective gear so you can begin treating patients at the scene.

B. Intercept anyone leaving the scene who appears to be medically affected by the chemical attack and provide each individual with on-the-spot medical care.

C. Use your cell phone to contact your colleague in your facility’s emergency department to ask what you should do.

D. Go home and follow your facility’s emergency plan procedure for clinician recall.

The best answer is (d): "Go home and follow your facility's emergency plan procedure for clinician recall."

Take a moment to reflect on the roles you might be asked to play in the hospital system in the aftermath of an emergency event.

In an emergency, your hospital's administration will activate the hospital's emergency response plan, which may include activating the Hospital Emergency Incident Command System (HEICS), a mechanism for organizing resources and personnel to respond in an effective, coordinated manner. Your hospital's response plan includes protocols for notifying hospital clinicians of emergencies and recalling them to assist in the emergency response. In some hospitals, clinicians will be notified by the hospital if their services are needed. In other hospitals, clinicians may be required to call a special phone number to receive instructions. However your facility's emergency plan is structured, make sure you are aware of these protocols ahead of time. In this scenario, going to the scene of the emergency would be counterproductive and dangerous. The presence of unauthorized personnel—however well-intended—distracts first responders from their work, slows the emergency response at the scene, and increases the risks for all concerned. Attempting to contact colleagues in the emergency department (ED) would only contribute to overloading the hospital's communication lines, which will be heavily burdened in any emergency. Moreover, such calls would distract ED staff from focusing on their primary responsibilities during a critical event.

Scenario Question 2:
In your capacity as a health-care professional, you are working your shift at the hospital on Sunday afternoon and learn of the chemical attack from the TV in a patient's room. You realize that your facility will soon begin receiving large numbers of victims. What should do you?
A. Hurry to the emergency room to offer your assistance.

B. Remain where you are, continuing to care for the patients on the floor, while awaiting further instructions.

C. Leave the floor and report to the hospital emergency operations center to offer your help.

D. Call the emergency operations center to alert them as to what has happened.

The best answer is (b): "Remain where you are, continuing to care for the patients on the floor, while awaiting further instructions."

There is a system in place to handle all types of emergencies, from hurricanes to terrorist acts. The system is HEICS, and we are all part of it.

Follow your usual routines until instructed to do otherwise. In an emergency, you may be assigned a functional role. Such roles are designed to reduce duplication of effort, prevent “freelancing,” promote efficiency, deploy clinicians to where they are most needed, and ensure a high level of coordination throughout the hospital and between agencies. In some cases, your role may simply be to continue to do what you normally do in providing or overseeing patient care until you are called upon to do something else. To maintain order and efficiency in your facility during an emergency, simply follow your usual routines until you receive additional instructions. Follow your hospital’s emergency response protocols by avoiding “freelancing,” which only undermines the hospital’s capacity to respond to a mass casualty event. Reporting to the emergency room or emergency operations center will distract those staff from their critical functions, as will telephoning the emergency operations center during a high-volume period. Remain at your post until you are notified of any changes in your functional role or responsibilities.



Chemical Incidents: Intentional Acts and Accidents

The threat of a mass casualty event resulting from an intentional or accidental release of dangerous chemicals is very real. Some countries have undeclared stockpiles of chemicals, others have secret chemical weapons development programs, and poorly secured caches of dangerous chemical materials are known to exist throughout the world.

Industrial chemical production facilities and their delivery systems are vulnerable to both terrorist acts and industrial accidents. Since 9/11, law-enforcement officials have stepped up routine monitoring of air quality and increased surveillance of small planes that might be used for deliberate release of noxious substances.

Hazardous-material shipments, which routinely travel along railroad and highway systems in heavily populated areas, are also vulnerable to accidents and sabotage. Indeed, accidents involving hazardous materials are not uncommon. In 2005, for example, a train accident in South Carolina caused the release of chlorine gas that killed nine people, injured 500, and led to the evacuation of 5,400 local residents.

Did you know?...

ABC News reports that "every day, sulphuric and hydrochloric acid, ammonia and chlorine are shipped by the ton via rail and truck. They are among the industrial chemicals used to manufacture everything from purified water to fertilizer, plastics and artificial turf used in stadiums. The chemicals are also lethal, capable of killing everyone in a small city in short order.

"More than 90,000 shipments of chlorine alone are transported across the country every year. According to a study by the Naval Research Lab, 100,000 people could die in only 30 minutes if there was a major breach of a single chlorine tanker in a populated area.

"If this accident occurred in Washington D.C., or Boston or New York we would not be talking about a handful of deaths, we would be talking potentially tens of thousands of deaths that would have occurred in a very short period of time,' said Rep. Ed Markey, D-Mass."

Source: ABC News, Growing Potential for Hazmat Accidents. http://abcnews.go.com/WNT/story?id=393986&page=1


Module Objectives

This module provides an overview of emergency preparedness in response to the accidental or intentional release of chemical agents. Upon completing the module, you will be able to:

  • Describe the various types of chemical-warfare agents.
  • Recognize the clinical picture associated with a chemical exposure.
  • Describe your role in the clinical management of a chemical exposure.
  • Recognize the basic safety procedures for protecting yourself, your patients, and your facility during a mass casualty event involving chemicals.
  • Describe how to increase your own emergency preparedness and your family’s preparedness.
  • Understand how your institution’s emergency management plan may operate during an emergency involving the release of dangerous chemicals.
  • Recognize your role within the emergency management structure.


Hospital Emergency Incident Command System (HEICS)

During a HEICS activation, your hospital’s leadership will deploy personnel throughout the hospital system as they are needed—to care for existing patients or to address the needs of new patients arriving at the hospital as a direct result of the event.

In the event of a mass casualty event, doctors, dentists, nurses, nurse practitioners, physician assistants, and other health-care professionals are likely to serve as secondary responders within the hospital system. To prepare for this possibility, you should become familiar with your hospital’s emergency management plan. In order for your hospital to respond effectively to an emergency, the hospital will activate a specific management model called the Hospital Emergency Incident Command System (HEICS). This model provides hospital leadership with a structure in which to manage the command, control, and coordination of the facility’s response. This system also allows for the integration of the hospital’s response with that of local, state, regional and federal authorities. Key to this system is a chain of command that controls and expedites the management of resources, including personnel, equipment, and facilities.

Scenario Question 3:
You are at home reading the Sunday New York Times online when a news alert appears on your screen regarding the chemical attack. As a medical provider, what should you do?
A. Rush to the nearest hospital—whether or not you have an affiliation there—and volunteer your services.

B. Rush to one of the scenes of the attack and offer your services to the first responders at the scene.

C. Gather your family together to review your Family Emergency Plan and make immediate preparations for the possibility that you will be called upon to work an extended shift at the hospital that may keep you away from home for an extended period of time.

D. Report to your hospital for duty right away.

The best answer is (c): "Gather your family together to review your Family Emergency Plan and make immediate preparations for the possibility that you will be called upon to work an extended shift at the hospital that may keep you away from home for an extended period of time."

Have you created a Family Disaster Plan and/or Personal Emergency Plan?

Before an emergency occurs, it is essential to plan for the safety of your family, elderly or dependent relatives, and pets. A major reason cited by health-care workers for being unwilling to report to work during an emergency is concern for their family's safety. Having a detailed plan will greatly facilitate your ability to fulfill your professional functions in a mass casualty event.

Be aware that it will be necessary for you to carry some form of identification (hospital ID or a state-issued clinician ID card) in order to pass through security checkpoints that may be established during a crisis. Before an emergency occurs, you should also take the time to familiarize yourself with alternative transportation routes/methods to reach your institution in an emergency. If your facility has created materials on alternative travel routes, be sure to study these materials in advance.


Clinician Roles and Possible Assigned Tasks

During a large-scale incident involving a chemical release, your hospital will activate its emergency response plan utilizing HEICS. The hospital administration will open the Incident Command Center — the hub of all major decision-making and coordination of the facility's activities throughout the HEICS activation. The Incident Command Center will operate under the management of the hospital's Emergency Incident Commander. At this point, functional role assignments will be made. As a clinician, you will most likely be assigned to the Operations Section, where you will work under the command of the Operations Section Chief. Your contribution to the hospital response will be to care for patients affected by the incident. As such, your functional role will probably be consistent with your clinical title: doctor, nurse, nurse practitioner, physician assistant, dentist, or other health-care professional. You may be assigned to do the same tasks you do every day or tasks that differ from your usual responsibilities.

Here is a listing of possible tasks you might be assigned:


  • Providing medical or nursing care to patients in units that are short-staffed because clinicians are unable to get to work or were assigned to other roles.
  • Discharging patients as part of the hospital’s surge capacity plan.
  • Caring for selected victims under the direction of the medical care director following established protocols.
  • Assessing the skills of the labor pool in anticipation of new functional role assignments.
  • Accompanying patients during intra- and inter-facility transport and assisting with care.

Staff Training:

  • Assisting in providing specialized “just-in-time” trainings.


  • Triaging family and concerned citizens to identify those with special mental-health needs.


  • Assisting the emergency department team in managing patient triage.


Safety Issues


An important safety issue pertaining to chemical incidents involves patient contamination and the potential for contaminated patients to infiltrate the hospital environment. In the event of a chemical release, first responders will arrive to secure the scene, identify the chemical agent(s), and implement appropriate hazardous-materials protocols. The first responders' focus will be on assisting incapacitated victims, performing triage, carrying out decontamination, and evacuating patients to nearby medical facilities.

However, in most instances, approximately 60–80% of the first patients to arrive at local hospitals following an emergency of this kind will have traveled to the hospital on their own. Such individuals are often described as “exposed but not incapacitated.” Since these patients are likely to be contaminated, hospitals have systems to protect other patients, hospital staff, and the facilities themselves from becoming contaminated. Today, hospitals have decontamination teams comprised of emergency department staff, security staff, and others. These teams are responsible for decontaminating patients before they enter the hospital environment. Decontamination involves removing the patient's clothing, washing the patient, and properly disposing of the contaminated clothing. Your hospital's emergency department conducts decontamination drills to prepare for such scenarios and is aware of its role in protecting the integrity of the hospital and the safety of those who work and receive care there.

In January 2005, the Occupational Safety and Health Administration (OSHA) released new guidelines for hospitals entitled OSHA Best Practices for Hospital-based First Receivers of Victims from Mass Casualty Incidents Involving the Release of Hazardous Substances. These guidelines provide employers with information on how to protect their employees from exposures to toxic substances, including chemical agents. Should secondary responders need to be recruited to perform their job in an area where they might be at risk for coming into contact with contaminated patients, these guidelines provide for an OSHA-approved basic training.

The emergency-preparedness activities undertaken by your facility are intended to minimize the likelihood that hospital clinicians will be exposed to contaminants or toxic agents in the workplace. At the same time, it is vital that clinicians maintain a high level of alertness to the potential of chemical exposures in patients encountered during their routine clinical duties. Given the current environment, it is possible that at some future time, you will see a patient who has been exposed to a chemical agent as the result of an accident or an intentional act. In this environment, clinicians must have a basic understanding of what to look for and how to report any suspicious findings within their hospital's hierarchy. Here are some tips to keep in mind:

  • Before any reporting occurs, you and the site staff should implement the following three steps for protecting yourself and others in the immediate vicinity of the suspected case: (1) identify, (2) isolate, and (3) contain.
  • If a person with a suspected chemical exposure comes into an off-site medical facility, you should call EMS.
  • If the suspected chemical exposure case comes into a hospital-based clinic, you should contact the emergency department.
  • Do not contact law enforcement authorities; instead, use your hospital’s chain of command and adhere to your hospital’s internal protocols for reporting known or suspected cases.

Personal and Family Preparedness

Clinicians need to keep in mind that chemical events could be either small or large, accidental or intentional, and that safety is paramount.

Responding to an emergency involving a chemical incident will challenge your knowledge and ability. Decontamination procedures address physical hazards, but, in the thick of an event, you have to know your own limitations, how to seek expertise, and how to manage psychological stress. One mechanism built into HEICS is the expectation that you will rely on your immediate supervisor in the chain of command. During an incident, you should be aware of who you report to and address your personal safety needs with that person.

During an emergency, it is not only your routine that will be affected but that of your family and loved ones. Part of emergency preparedness is the development of a Personal Emergency Plan and Family Disaster Plan which address the needs of your children, elderly relatives, even pets, should you not be available. Completing a Personal Emergency Plan and Family Disaster Plan can help you organize and document who you designate as the care giver(s) for your loved ones. Pre-planning, and communication of your plans, helps alleviate some of the stress induced during the emergency.

Do you have a Family Disaster Plan and Personal Emergency Plan?


Chemical Agents Overview

Understanding the Clinical Picture


To determine treatment for a chemical agent, the clinician may choose to place the presenting signs and symptoms into groups known as “toxidromes.” In doing so, the clinician need not identify the exact substance a patient has been exposed to; rather, the clinician needs only to recognize a group of findings to determine a possible cause and, through this, a treatment pathway.

For example, the following is a toxidrome created to highlight the common set of symptoms exhibited by someone exposed to a blistering agent or vesicant.

  • Eye burning
  • Blurry vision
  • Respiratory difficulties and a burning sensation inside the lung
  • Skin burning

Toxic Targets

In evaluating a patient, the clinician can determine the kind of exposure by reviewing:

  • Airways
  • Breathing
  • Circulation
  • Disability (neurological)
  • Exposure (skin)

These systems can be considered the chemical agents' “Primary Targets.” Once you have clustered the symptoms, it is easier to determine which systems are being affected by the agent. The cluster of symptoms shown in the toxidrome above demonstrates that the agent is predominantly an airway and skin irritant; in this instance, the Primary Targets are Airway and Exposure (skin).

Identifying the Right Treatment

Once you have identified the symptoms, you can determine the appropriate treatment. Chemical exposure treatment decisions can be remembered by using the following ABCDE mnemonic device:

  • Can you alter the Absorption or does the chemical have an Antidote?
  • Have you checked the Basics, such as the airways, breathing, and circulation?
  • Can you Change the agent's Catabolism, Distribute it Differently, or perhaps Enhance its Elimination?

Summary of Chemical Agents

AGENT --> Nerve Blistering Choking Blood
Contamination Yes Yes Yes No
Environmental Integrity Compromised Compromised Compromised Intact
Main Clinical Features: -Diarrhea
-Altered mental status
-Eye burning
-Blurry vision
-Respiratory difficulties
-Skin burning
-Coughing, gagging, and choking
-Eye burning -Lightheadedness
-Dizziness and vomiting
-Lacrimation, rhinorrhea, and bronchorrhea may occur
Toxic Targets Airway
Treatment Atropine
2-PAM (an oxime)
Mustard: None
Lewisite: BAL
Supportive care
Supportive care O2 support
Cyanide: Taylor Pharmaceuticals cyanide antidote kit (formerly known as the Pasadena or Lilly Kit)


Case Studies

The following case studies give you an opportunity to explore the signs, symptoms, and treatments for exposure to nerve agents, blistering agents, choking agents, and blood agents. The case studies also illustrate some of the potential functional roles you might be assigned during a mass casualty event involving chemical agents.

Case A
Two hours after being exposed to a chemical agent at Macy's, a 35-year-old patient at your hospital has diarrhea and is constantly urinating, sweating, and vomiting. The pupils of her eyes are very small. To what class of chemical agents has this patient been exposed?
A. Nerve Agents
B. Vesicants or Blistering Agents
C. Choking Agents
D. Blood Agents
Correct answer: This patient is exhibiting symptoms of exposure to nerve gas. The appropriate treatment is atropine.

Case B
Three days after being exposed to a chemical agent at the Westchester mall, a 55-year-old patient who was close to the chemical's point of release has burns on his body, bloody diarrhea, and low white cell, red cell, and platelet counts. To what class of chemical agents has this patient been exposed?
A. Nerve Agents
B. Vesicants or Blistering Agents
C. Choking Agents
D. Blood Agents
Correct answer: This patient is exhibiting symptoms of exposure to mustard gas, which is a vesicant or blistering agent. Treatment is mostly supportive, with supplemental oxygen and monitoring for infections in the wounds.

Case C
One day after being exposed to the chemical attack at the Long Island Rail Road station, a 15-year-old hospitalized girl is putting out almost a liter of fluid per hour from her lungs. To what class of chemical agents has this patient been exposed?
A. Nerve Agents
B. Vesicants or Blistering Agents
C. Choking Agents
D. Blood Agents
Correct answer: The girl was exposed to phosgene, a choking agent. She is suffering from non-cardiac pulmonary edema. She needs to be in a critical-care unit with supplemental oxygen.

Case D
A 50-year-old man arrives at a non-hospital-based clinic complaining of lightheadedness, nausea, weakness, excessive sweating, and dimmed vision. He reports that these symptoms appeared soon after he unwrapped a sealed package from an unknown sender. To what class of chemical agents has this patient been exposed?
A. Nerve Agents
B. Vesicants or Blistering Agents
C. Choking Agents
D. Blood Agents
Correct answer: The patient was probably exposed to nerve gas. The clinician at the non-hospital-based clinic should first carry out three steps for protecting everyone in the immediate vicinity of the suspected case: (1) identify, (2) isolate, and (3) contain. The clinician should then immediately contact EMS to report the suspected case.

Case E
A woman brings her 10-year-old daughter to see the pediatrician in a hospital-based clinic because the girl is complaining of shortness of breath and burning eyes. About 45 minutes earlier, the girl had been playing outside when she heard what sounded like a car crash and saw a greenish-yellow cloud rise into the air. To what class of chemical agents has this patient been exposed?
A. Nerve Agents
B. Vesicants or Blistering Agents
C. Choking Agents
D. Blood Agents
Correct answer: The girl was probably exposed to chlorine gas, a choking agent released from a vehicular accident. The clinician should contact the Emergency Department (ED) and have the patient and her parent escorted to the ED. The ED would probably notify the hospital Administrator on Duty (AOD), placing the call to notify the hospital administration that an accident involving a chemical release had occurred. The ED and AOD would then monitor the incident to assess the need for additional action.


Scenario Continued...

Soon after the chemical attacks at the mall and in Manhattan, law-enforcement officials determined that phosgene, sarin, and mustard gas were released during the attack. Area hospitals were locked down, with entrances guarded by security. Hundreds of patients were triaged, evaluated, and sent home. Hundreds more were admitted to surrounding hospitals and several dozen died at the scene. In the immediate aftermath of the event, thousands of people gathered outside area hospitals seeking information about their family members and requesting screenings for possible exposure.

Scenario Question 4:
You and two other medical providers have been asked to assist 50 family members of persons killed and wounded by the chemical attack. These family members are gathered in the hospital’s auditorium. After providing nonstop patient care to the victims of the emergency for the past 12 hours, you are exhausted, hungry, and beginning to feel ill yourself. What should you do?
A. Tell your colleagues that you are going to take a short break.

B. Seek medical care in the emergency department.

C. Inform your supervisor that you are not feeling well and are requesting a break.

D. Take a sip of water and soldier on with the task you have been assigned.

The best answer is (c): "Inform your supervisor that you are not feeling well and are requesting a break."

The HEICS model provides a predictable chain of command that must be followed to promote coordination, efficiency, and appropriate support for medical personnel. Your supervisor in the chain of command is responsible for your welfare and safety. If you feel the need for rest, food, or some other form of support during an extended work shift, you should approach your supervisor to request such support. Abandoning your post to take a break or visit the emergency department on your own would increase the burden on your colleagues and create confusion. Instead, use the chain of command to ensure that your safety and health are maintained during a stressful and demanding emergency response shift. Be attentive to your needs and do not try to “soldier on” to the point where your safety and well-being are compromised. Communicating with your supervisor in the chain of command will ensure that your needs are met and that appropriate coverage for your position can be arranged.

Scenario Question 5:
In the aftermath of the chemical attack, you are assigned the task of transporting several patients to a nearby community-based facility. However, as you approach the patients you realize that, although they were supposed to have been decontaminated, a few still seem to have a greasy substance near the roots of their hair. What should your initial response be?
A. Attempt to wash off the greasy material yourself.

B. Be cautious about approaching patients with the greasy substance.

C. Contact your supervisor to express your concerns.

D. Rush everyone back to the decontamination area before moving them to another site.

The best answer is (b): "Be cautious about approaching patients with the greasy substance."

Protecting yourself and other staff first is paramount, so exercising caution is the appropriate initial response. This is especially so given that you know there has been an incident involving a chemical release. The very next step would be to contact your supervisor in the chain of command, who might then contact the decontamination team for instructions on how to proceed. Never attempt decontamination if you are not appropriately trained or explicitly instructed to do so and do not move patients to locations where you have not been instructed or authorized to do so.



In their day-to-day medical practices, many clinicians act as independent agents within the hospital hierarchy to provide the best care for their patients. However, in an emergency or mass casualty event, your hospital will activate the Hospital Emergency Incident Command System (HEICS). Under this system, you and your colleagues will be required to function within a predictable chain of command to ensure clear lines of responsibility and communication throughout the emergency response. Becoming familiar with this system and your institution's emergency management plan will help you understand your potential role in a mass casualty event.

Given the current environment, awareness of emergency preparedness as it relates to chemical incidents is vitally important. Preparation for the possibility of a serious chemical accident or terrorist attack includes awareness of the various classes of chemical agents, the signs and symptoms associated with each agent type, treatment protocols, and safety issues affecting you, your colleagues, your patients, and the hospital as a whole. This module was designed to provide this initial overview. We encourage you to explore the other modules in this series to deepen your understanding of emergency preparedness, your role in this process, and the various medical issues at play in responding to mass casualty events.

Source Material

Vesicant or Blistering Agents

Vesicant or Blistering Agents
www.atsdr.cdc.gov/tfacts165.html - ToxFAQs
www.atsdr.cdc.gov/MHMI/mmg165.html - Medical Management Guidelines

Centers for Disease Control and Prevention
www.bt.cdc.gov/agent/vesicants/tsd.asp - Facts about vesicants
www.bt.cdc.gov/agent/sulfurmustard/basics/facts.asp - Facts about sulfur mustard

Choking Agents

Agency for Toxic Substances and Disease Registry
www.atsdr.cdc.gov/tfacts165.html - ToxFAQs
www.atsdr.cdc.gov/MHMI/mmg172.html - Medical Management Guidelines

Centers for Disease Control and Prevention
www.bt.cdc.gov/agent/chlorine/basics/facts.asp - Facts about chlorine

Agency for Toxic Substances and Disease Registry
www.atsdr.cdc.gov/tfacts176.html - ToxFAQs
www.atsdr.cdc.gov/MHMI/mmg172.html - Medical Management Guidelines

Centers for Disease Control and Prevention
www.bt.cdc.gov/agent/phosgene/basics/facts.asp - Facts about phosgene

Blood Agents

Agency for Toxic Substances and Disease Registry
www.atsdr.cdc.gov/tfacts8.html - ToxFAQs
www.atsdr.cdc.gov/MHMI/mmg8.html - Medical Management Guidelines
www.atsdr.cdc.gov/toxprofiles/phs8.html - Public Health Statement

Centers for Disease Control and Prevention
www.bt.cdc.gov/agent/cyanide/basics/facts.asp - Facts about Cyanide

New York State Department of Health, The Facts About Cyanides (General Information Fact Sheet)

Nerve Agents

Agency for Toxic Substances and Disease Registry
www.atsdr.cdc.gov/tfacts8.html - ToxFAQs
www.atsdr.cdc.gov/MHMI/mmg8.html - Medical Management Guidelines

Centers for Disease Control and Prevention
www.bt.cdc.gov/agent/vx/basics/facts.asp - Facts about VX www.bt.cdc.gov/agent/sarin/basics/facts.asp - Facts about sarin

News Articles

Sarin Incident in Japan

Pollack, A. "Terror in Tokyo, Survivors Stories: How a Morning Routine Turned to Horror," New York Times, March 21, 1995.
Altman, L. "Nerve Gas That Felled Tokyo Subway Riders Said to Be One of the Most Lethal Known," New York Times, March 21, 1995.

Chlorine Accident in South Carolina

Hamilton, P. "Eight killed, 240 treated in South Carolina train wreck that released chlorine gas," Associated Press, January 7, 2005
ABCNEWS.com. "Growing potential for hazmat accidents," http://abcnews.go.com/WNT/story?id=393986&page=1, January 7, 2005

Other Materials of Interest

Carnegie Endowment for International Peace
http://www.carnegieendowment.org/ - (background information on chemical weapons).

Centers for Disease Control and Prevention, "Recognition of Illness Associated with Exposure to Chemical Agents," United States, 2003.
www.cdc.gov/mmwr/preview/mmwrhtml/mm5239a3.htm - October 3, 2003.

Greater New York Hospital Association Chemical Resource Page

HRSA Training and Curriculum Grant Awardee Conference Presentation, "The Oklahoma City Experience and the Role of the Medical Volunteer," by Mike Murphy, MMRS Director OKL/Tulsa, May 26, 2004.

Occupational Safety and Health Administration (OSHA), "OSHA Best Practices for Hospital-based First Receivers of Victims from Mass Casualty Incidents Involving the Release of Hazardous Substances," www.osha.gov/dts/osta/bestpractices/ firstreceivers_hospital.pdf, January 2005.

Qureshi, K.A., Gershon, R.R.M., Sherman, M.F., Straub, T., Gebbie, E., McCollum, M., Erwin, M.J., Morse, S.S. "Health Care Workers" Ability and Willingness to Report to Duty During a Catastrophic Disaster, Journal of Urban Health: Bulletin of the New York Academy of Medicine, 2005,82(3), pp.378-388.


Chemical Agents: Nerve Agents


Nerve agents are the most toxic and rapidly acting of the known chemical-warfare agents. Originally synthesized in the 1930s by German scientists developing pesticides, nerve agents' poisonous nature against humans quickly became apparent. Researchers working with these chemicals exhibited shortness of breath and miosis, and almost died. Soon afterward, the German military exploited a related substance, called sarin, as a weapon. In the late 1950s, the United States, with assistance from the British government, began the production of VX, a chemical warfare agent. Terrorists in Japan used sarin on Japanese citizens in 1995. In the late 1980s, sarin and VX were used against the Kurds by the Iraqi regime. Stockpiles of these chemicals can be found in the arsenals of several governments throughout the world. Both sarin and VX can be aerosolized, with VX being more persistent in the environment.

Nerve agents are similar to organophosphate pesticides in how they work and in their effects, but they are far more potent. They interfere with acetylcholinesterase by forming an irreversible covalent bond that renders the enzyme inactive, thereby enabling the chemical's continued effect. VX and sarin are liquids at ambient temperature. Sarin is yellowish, mixes easily with water, and is volatile and easily aerosolized, thereby presenting an immediate but short-term effect. Sarin's vapor is heavier than air, creating a hazard in low-lying areas. VX, which is 150 times more toxic than sarin, has the consistency of motor oil, is persistent in the environment, and can last on surfaces for some time, posing both short- and long-term hazards.

Did you know?...

In 1995, to release sarin into a suburban Tokyo subway station, terrorists poked holes into containers of sarin. The heat and movement of passengers caused the sarin to vaporize, and owing to sarin's high density, seated passengers were particularly affected. The sarin incident was an unfortunate illustration of how first responders at a scene can become ill when proper precautions are not taken. In this instance, 132 first responders became ill because of their failure to suspect a chemical agent and use personal protective equipment. In addition, Tokyo hospitals were unprepared for the attack. Hospital staff did not know that something had happened until victims started showing up by foot or by car at the emergency room. Traffic blocked ambulances from getting to the emergency department. Ultimately, 12 people died, 1,000 were hospitalized, and 5,500 sought medical treatment.

Signs and Symptoms

Nerve agents penetrate the skin, lungs, and mucous membranes; symptoms can appear within minutes of exposure. Heavy exposure to sarin or VX will cause loss of consciousness, seizures, and death. Often, diagnosis of nerve agent exposure must be made clinically, due to the time frames required to obtain confirmatory test results. The extent of poisoning will depend on the amount of exposure, the manner in which the patient was exposed, the patient's distance from the point of release, and the length of exposure. An individual with significant exposure to nerve agents will experience a characteristic leakage of fluids from every orifice.

In reviewing the chart below, note the use of mnemonic devices to aid in clinical diagnosis. The muscarinic PNS symptoms use the mnemonic DUMBELS. The nicotinic PNS symptoms use the first letters of the days of the week (MTWtHF) as a memory aid. The mnemonic trigger for remembering the CNS symptoms is the “three Cs.”

Toxidromes for a Nerve Agent Exposure

PNS (Peripheral Nervous System) PNS (Peripheral Nervous System) CNS (Central Nervous System)
Muscarinic Nicotinic Central
Diarrhea Mydriasis Confusion
Urination Tachycardia Convulsions
Miosis Weakness Coma
Bradycardia, bronchorrhea / spasm Hypertension, hyperglycemia
Emesis Fasciculations
Salivation, secretion, sweating

Toxic Targets

Body Component Toxic Target
Disability (neurological)
Exposure (skin)


If a patient has pinpoint pupils, fasciculations, and an altered mental state, he or she most likely has organophosphate poisoning, because little else will produce such symptoms. The fasciculations may be fine and in the lower extremities, so clinicians may have to look carefully for the twitching.

If an on-site clinician suspects exposure to a nerve agent, and the patient has not come through a hospital's emergency department, the clinician should first protect himself or herself, then contact the emergency department. If the clinician is off-site, the clinician should contact emergency medical services to arrange transport to the hospital. Treatments, based on the symptoms presented, will be:

  • Atropine (for the muscarinic, or DUMBELS, symptoms)
  • 2-PAM (for the nicotinic, or MTWtHF, symptoms)
  • Benzodiazepines (for the three Cs)

Atropine is given until the secretions begin to dry and the patient is able to breathe. If a patient comes in with tachycardia, it is acceptable to give atropine, even though it is indicated for bradycardia. Hypoxia from the pulmonary secretions results in a reflex tachycardia. 2-PAM should to be given to individuals who exhibit weakness or muscle fasciculations. It should be administered to those exposed to sarin within 4-6 hours and to individuals exposed to VX within 60 hours. By pulling the nerve agent off of acetylcholinesterase, irreversible injury can be prevented. A delay in initiating treatment may result in irreversible enzyme injury and a significant delay in patient recovery. This recovery period may be as long as two months as the body regenerates acetylcholinesterase de novo. Benzodiazepines are indicated in the agitated, combative, or seizing patient.


Chemical Agents: Vesicants or Blistering Agents


Vesicants, such as mustard gas and lewisite, represent a type of chemical-warfare agent that causes blistering of the skin and the mucous membranes. Mustard gas is so named because it can smell like garlic, onions, and burnt mustard seeds—although in some cases, it has no odor. Although called a “gas,” sulfur mustard (mustard gas) has the viscosity of motor oil, is persistent in the environment, and poses a threat as both a liquid and a vapor.

Mustard gas was introduced during World War I, with the Germans successfully employing this agent on the Western front. Mustard gas is an effective chemical-warfare agent because of its delayed onset of symptoms, in particular its ocular and dermatologic effects. When used in World War I, limited exposure resulted in the death of fewer than 5% of those exposed. Today, more than a dozen countries include mustard gas in their chemical arsenals.

Signs and Symptoms

Mustard gas can cause death as the result of systemic effects (e.g., bone-marrow suppression or gastrointestinal problems) that occur within a week of exposure. Mustard gas affects the eyes, lungs, skin, circulation, and gastrointestinal system.

Symptoms can take time (1-24 hours after exposure) before they develop. The onset of a burning sensation can occur between 2-48 hours after exposure, but typically occurs within 3-8 hours. Because of this latent period, clinicians need to be extremely careful to avoid contaminating themselves or others when treating persons who may have been exposed to mustard gas.

Mustard gas exerts its effect in a manner similar to radiation, causing cell damage within 1-2 minutes of exposure. The chemical binds to intra- and extra-cellular proteins, enzymes, and alkylates DNA.

Clinical Picture of a Mustard Gas Exposure

The Eye

  • Mild exposure can lead to conjunctivitis.
  • Moderate exposure can cause chemosis (swelling of the eye membrane), and blepharospasm (abnormal blinking).
  • Severe exposure can lead to corneal opacification.


  • Irritation of nose, sinuses.
  • Pharyngitis.
  • Destruction of the airway mucosa of smallest bronchiole.


  • Within one day, nausea and vomiting, and cholinergic effects.
  • In 3-5 days, tissue destruction and sloughing; also bloody diarrhea, an indication of significant exposure.

The Skin

  • Mustard gas is very lipophilic and rapidly penetrates the skin.
  • It causes erythema, small vesicles that coalesce, and blisters.
  • Coagulation of blisters leads to necrosis.
  • The fluid in the vesicles is not toxic.

Bone Marrow

  • Mustard gas causes direct injury to stem cells and bone marrow.
  • Within 3-5 days, white blood cell, red blood cell, and platelet counts fall.
  • Patient rarely survives if white blood cell count drops below 200.
  • Mimics radiation poisoning.

Of Those Who Die of Mustard Gas Exposure:

  • 2% die in the first 24-48 hours, as a result of acute causes, such as from a high inhaled dose.
  • 80-90% die within 6-11 days, as a result of systemic effects (e.g., bone-marrow suppression, gastrointestinal problems, etc.) .

Vesicant Toxidrome

  • Eye burning
  • Blurry vision
  • Respiratory difficulties and a burning sensation inside the lung
  • Skin burning

Toxic Targets

Body Component Toxic Target
Disability (neurological)
Exposure (skin)


There is no antidote to mustard gas. The antidote to lewisite is called British Anti-Lewisite (BAL). Medical management is mainly supportive and depends on the part of the body affected. An overriding concern is to keep wounds of the skin, eye, and airway free from infection. Large skin lesions may need irrigation, with the patient getting analgesics beforehand, and, if evidence of infection is present, systemic antibiotics. Eye solutions can help the milder conjunctivitis cases, but severe lesions may need more aggressive treatment, including antibiotics and petroleum jelly applied at the lid edges, several times a day, with analgesic supplementary care. Patients with severe airway damage should receive oxygen-assisted ventilation. If there are signs of significant airway injury, the patient may need to be intubated and treated in a critical-care unit. For patients experiencing bone-marrow suppression, consideration should be given to transferring the individual to an oncology or burn unit for reverse isolation and possible blood transfusion.


Chemical Agents: Choking Agents


The first chemical agent used during warfare was chlorine gas, deployed during a battle in World War I. The British quickly sought to develop their own capability and retaliated with their own gas attack, ushering in the era of modern chemical warfare. The choking agent phosgene was developed and introduced shortly thereafter. Chlorine caused victims to cough violently and choke, but phosgene was more deadly, in that those exposed didn't cough as much and inhaled more, with the onset of symptoms showing up almost a day later.

Today, chlorine is one of the major industrial chemicals employed in the United States, used as bleach in paper and cloth production and in the manufacture of pesticides, rubber, and solvents. Chlorine is transported as a liquid, which if released turns into a gas that stays close to the ground and spreads rapidly. The gas has a strong, pungent odor of bleach, although only 50% of exposed persons can perceive the odor at the OSHA permissible level (5 ppm).

Phosgene is used to make dyes, coal tar, and pesticides. As a gas, phosgene may appear colorless or as a white or pale-yellow cloud, which at low concentrations has the odor of newly mown hay or green hay. Both chlorine and phosgene are heavier than air and settle in low-lying areas.

Signs and Symptoms

Severe chlorine and phosgene exposure leads to non-cardiac pulmonary edema. Clinicians who suspect that individuals have been exposed to chlorine or phosgene need to be aware of the victims' potential for off-gassing from the folds of their clothing. Therefore, clothing should be removed from a patient's body as soon as possible.

Chlorine gas combines with water to form hydrochloric acid, but the chlorine itself is more irritating to the lungs than the acid. Those exposed to chlorine present with coughing, gagging, and choking. Chlorine binds to tissue that is high in water content and therefore principally affects the eyes, nose, and upper airway. Coughing, however, prevents deep pulmonary penetration. Delayed effect from high exposure is non-cardiac pulmonary edema. Patients may produce as much as a liter of fluid per hour from the lungs.

The major cellular damage from phosgene is due to the carbonyl group. Because phosgene does not elicit coughing, the gas penetrates deeply into the airways, damaging the alveolar capillaries. Individuals exposed to phosgene may not have symptoms for 2-24 hours, but can develop non-cardiac pulmonary edema and may produce a liter of fluid per hour from the lungs.

Choking Agent Toxidrome

  • Coughing, gagging, and choking
  • Burning eyes
  • Lightheadedness
  • Confusion

Toxic Targets

Body Component Toxic Target
Disability (neurological)
Exposure (skin)


Treatment for chlorine and phosgene exposure depends on the symptoms, but bed rest and supportive care (including supplemental oxygenation and ventilatory support, fluid resuscitation, nutrient supplement, and good infection control practices) define the traditional therapy. People exposed to phosgene should be watched for up to two days, because it may take that long for symptoms to present. Severe cases may require care in the critical-care unit with supplemental oxygen. Children may be more vulnerable to choking agents because of the smaller diameter of their airways and because, being closer to the ground, they may be exposed to higher amounts of these chemicals, which concentrate in low-lying areas.


Chemical Agents: Blood Agents


Cyanides were first discovered in 1704, when German scientists experimenting with the development of paint pigments mixed blood with adulterated potash and came up with a deep blue pigment now known as Prussian blue. An industry of cyanide dyes developed, and later in the 18th century, Prussian blue was mixed with sulfuric acid to create hydrogen cyanide gas.

Cyanides were used in warfare during World War I, and later by the Nazis. In 1985, members of an extremist group attempted to poison the water supply of a major metropolitan city with cyanide but were intercepted.

Today, cyanides are used in the manufacture of plastics and paper, in agriculture, and in metal plating and photography. Cyanides are a significant combustion product of burning plastics and other synthetic materials, and victims of home and industrial fires may be exposed to cyanide poisoning as a result of this product's widespread use in home and industrial construction.

Cyanides are found in liquid, solid, and gaseous forms. Two military grades of cyanide that are cause for concern are hydrogen cyanide and cyanogen chloride. Cyanogen chloride is less volatile and therefore more effective than hydrogen cyanide. For hydrogen cyanide to be significantly toxic, it must be released in a small, enclosed space; in large open area it dissipates. Hydrogen cyanide gas has an almond scent, but some individuals cannot detect the smell, so it is not a reliable warning of contamination. High doses of cyanides will cause abrupt heart and brain dysfunction, and lead to death within minutes.

Signs and Symptoms

Cyanides work by binding to the iron in hemoglobin, preventing oxygen use and aerobic respiration inside the cell. Tissues that rely heavily on oxygen, such as the heart and the brain, are affected first.

Low-dose exposure
  • Anxiety, hyperventilation, headache, dizziness, and vomiting. Cyanogen chloride also can cause bronchorrhea, rhinorrhea, and lacrimation. Patients who are able should assist with their own decontamination.
Moderate-dose exposure
  • Respiratory distress with normal oxygen saturation. Metabolic acidosis soon sets in and oxygen levels in the blood get higher. A blood sample will show venous blood looking bright red, like arterial blood.
High-dose exposure
  • In 15 seconds, hyperpnea and seizure in 30 seconds.
  • Within 3-5 minutes, the individual stops breathing.
  • In 6-10 minutes, the patient dies.
  • Pupils can be normal or dilated.
  • Not initially cyanotic.

Blood Agent Toxidrome

  • Anxiety
  • Hyperventilation
  • Headache
  • Dizziness and vomiting
  • Also, lacrimation, rhinorrhea, and bronchorrhea may occur

Toxic Targets

Body Component Toxic Target
Disability (neurological)
Exposure (skin)


A cyanide antidote kit (formerly known as the Pasadena or Lilly Kit) is available from Taylor Pharmaceuticals to treat cyanide poisoning. The kit's use should be limited to those individuals experiencing significant symptomatology. Treatment of highly symptomatic patients involves supportive high doses of oxygen and use of the kit, which includes amyl nitrite pearls, sodium nitrite, and sodium thiosulfate. Sodium nitrite makes methemoglobin, which cyanide prefers over regular hemoglobin. Sodium thiosulfate helps remove cyanide from hemoglobin and changes its catabolism. Activated charcoal, which adsorbs the cyanide, may be considered for the treatment of ingested cyanide. Supportive care for those with high exposure and symptoms may be necessary.