CHEMICAL TERRORISM PREPAREDNESS AND RESPONSE

Chemicals are part of our daily lives, existing in the products we use every day. All chemicals can result in problems if used improperly and can be destructive when used as an agent of terrorism.

Chemical weapons cause injury or death by means of their high toxicity, usually when inhaled or in contact with the skin. The first widespread use of chemical weapons was in World War I. By the end of the war, seventeen different toxic agents had been used to kill 100,000 soldiers and civilians and injure at least a million more.

In 1925 the Geneva Protocol prohibited the use of chemical and biological weapons in war, and at a subsequent United Nations Conference in 1997, a Chemical Weapon Convention banned the use of chemical weapons as well as their development, production, stockpiling, and transfer. Destruction of these weapons, however, has been slow, and there are tens of thousands of tons still stockpiled in arsenals around the world.

Agents used in chemical terrorism include poisonous vapors, aerosols, liquids, or solids, all of which are volatile and have toxic effects on either humans, animals, or plants. Some of these chemical agents can be undetectable, as they may be odorless and tasteless, and they can have an immediate or a delayed effect. However, chemical agents dissipate quickly in open air and can be difficult to deliver in lethal concentrations. They are also difficult to produce (Williams et al., 2021; Arms Control Association, 2020).

Weaponization of Chemical Agents

Several factors must be considered when deciding how to deliver a chemical agent to a target. These include lethality, persistency, and physiological effect.

The amount of agent needed to produce incapacitation or death varies with the type of agent. Older agents require burdensome amounts of chemical on a target. The creation of nerve agents allows for an increase in lethality and decrease in quantity that needs to be delivered.

Some agents are persistent, remaining in effect for extended lengths of time, and others are nonpersistent, dissipating in minutes or a few hours. Persistent agents are most dangerous to the skin, and nonpersistent are more dangerous to the lungs (WPNAC, 2021).

Dispersal of Chemical Agents

Toxic chemicals can enter the body in several ways, most importantly through inhalation or absorption through the skin. In general, the effect of an agent in contact with the skin is much slower than when inhaled.

Chemical agents can be dispersed in gas, liquid, and solid forms by aerosolization, an exploding device, or contaminating food or water. They can be released by bombs; sprayed from aircraft, boats, or vehicles; or used in liquid form to create a hazard to people and the environment.

These weapons can be unitary or binary. Unitary weapons are effective on their own and do not require mixing with other agents. They are stored in ready-to-use form and pose a considerable risk to those working with them.

Binary weapons development began in the 1960s and involve the use of toxic agents and nontoxic precursors. When these weapons are deployed, the precursors mix with and develop the agent. Binary agents are safe to handle and store and are harder to detect (Velez-Daubon et al., 2021).

Categories of Chemical Weapons

There are five major types of chemical agents:

• Vesicants (blister agents)
• Lung-damaging (pulmonary) agents
• Blood agents
• Nerve agents
• Incapacitating agents/riot control agents
  (Williams et al., 2021)

VESICANTS (BLISTER AGENTS)

A vesicant, or blister agent, is named for its ability to cause severe and painful chemical water blisters on the bodies of affected persons. Vesicants have medical uses but are fatal if small amounts are ingested. Casualties generally result from absorption through the skin and require three weeks to three months for recovery.

Vesicants are oily reactive chemicals that combine with DNA and proteins to cause cellular changes within minutes to hours after exposure. Some agents have characteristic odors (e.g., sulfur mustard has been described as smelling like mustard, garlic, horseradish, or asphalt; and lewisite smells like geraniums). These agents include:

• Distilled mustard
• Mustard gas
• Mustard/T
• Sulfur mustard
• Nitrogen mustard
• Mustard/Lewisite
• Lewisite
• Phosgene oxide

Factors that contribute to the time of onset and the severity of illness include the:

• Amount and route of exposure to the vesicant
• Type of vesicant
• Baseline health condition of the exposed person
  (Williams, et al., 2021)

BLISTER AGENTS

Signs/Symptoms	Mustard compounds target the skin, eyes, respiratory tract, and bone marrow, causing: Intense and increasing skin pain, erythema and blister formation after a latent period of at least a few hours and up to 36 hours. Blisters may become large and pendulous. Painful conjunctivitis, with reflex lid closure occurs and cloudy cornea, possible blindness; earlier than skin symptoms Respiratory manifestations, including: Blister formation in the lungs Cough Hoarseness Laryngospasm Wheezing Inspiratory stridor Chest tightness and dyspnea with severe exposure Gastrointestinal symptoms, including: Nausea, vomiting, painful diarrhea, and prostration initially Vomiting and bloody diarrhea beginning days after high-dose exposure, which imply a poor prognosis Bone marrow suppression Lewisite causes: Pain within a minute of skin exposure Erythema, noticeable within 15–30 seconds, and blisters after several hours Irritation of mucosal membranes and large airways soon after inhalation, leading to coughing, sneezing, and wheezing Chest tightness and shortness of breath after a few hours Phosgene oxime causes: Intense pain and blanching within 5–20 seconds following skin exposure Gray skin with erythematous border following skin exposure Edema leading to urticaria between 5–30 minutes after exposure During the next 7 days, black skin and underlying subcutaneous and muscle tissue due to necrosis; may persist for more than 6 months if not managed surgically Pulmonary edema even at low dose exposures
Treatment	First Responder: Prioritize all casualties with potential skin or eye exposure to vesicants for immediate decontamination. Except for patients with impending airway compromise, most exposed to vesicants can tolerate a short delay in treatment. First Receiver: Decontamination Intramuscular British Anti-Lewisite (BAL, Dimercaprol) Treating skin lesions similar to thermal burns Scrupulous hygiene to prevent secondary infection High-dose steroids to reduce respiratory swelling Antibiotic ointment to edges of eyelids to prevent lid adhesion Supportive respiratory care Bone-marrow suppression, requiring reverse isolation and treatment with colony-stimulating factor Neupogen
Personal Protective Equipment	First Responders: Level A First Receivers: After completion of decontamination, Level C

CHOKING AGENTS

Choking/lung/pulmonary agents are chemicals that cause severe irritation or swelling of the respiratory tract (lining of the nose, throat, and lungs). Chemicals such as ammonia, chlorine, and phosgene cause eye, nose, and throat irritation, cough, wheezes, and dyspnea, which is known as irritant gas syndrome.

Clinically relevant routes of exposure include the mouth, nose, and mucosal membranes. The organ systems generally affected include the upper respiratory tract (airway and bronchi) and lower respiratory tract (air space and alveoli).

These agents include:

• Chlorine
• Phosgene
• Ammonia
  (U.S. DHHS, 2021b)

CHOKING AGENTS

(U.S. DHHS, 2021b)
Signs/Symptoms	Initial effects: Respiratory distress/shortness of breath Increased shallow/and or rapid breathing Presence or absence of secretions Coughing Use of accessory muscles Tri-pod positioning Upper respiratory effects (immediate): Wheezing Stridor Nasal and oral secretions Excessive lacrimation Lower pulmonary effects (progressive): Rhonchi Rales Absent breath sounds Progression may include: Bronchial spasm Respiratory failure if left untreated
Treatment	First responder: On-site decontamination; if done within 1–2 minutes of exposure, can minimize further tissue damage On-site ALS care prior to transport First receiver: No antidotes available Monitoring for first 48 hours for delayed effects Intensive care for symptom-related support
Personal Protective Equipment	First responders: Level A until decontamination has been completed First Receivers: After decontamination, Level C

BLOOD AGENTS

A blood agent is a toxic compound that affects the body by being absorbed into the blood and blocking the enzyme necessary for aerobic metabolism, depriving red blood cells of oxygen and causing asphyxiation. They are fast-acting, highly lethal toxins that are typically volatile colorless gases. They are usually either arsenic or cyanide-based, and include:

• Hydrogen cyanide
• Cyanogen chloride

Hydrogen cyanide can be dispersed as a nonpersistent vapor and can break down gas-mask and vehicle filters. Hydrogen cyanide smells like peach pits or bitter almonds.

People exposed to a small amount of cyanide by breathing it, absorbing it through their skin, or eating foods that contain it may have some or all of the following signs and symptoms and will die within 1 to 20 minutes.

BLOOD AGENTS

(Williams et al., 2021; WPNAC, 2021)
Signs/Symptoms	Convulsions Cyanosis Fatigue Headache Hyperventilation Hypotension Lightheadedness Loss of consciousness Metabolic acidosis Palpitations Nausea Nausea and vomiting Paralysis
Treatment	100% oxygen Sodium thiosulfate injection, 12.5 g/50 ml (2 vials) Sodium nitrate, 300 mg/10 ml (2 ampules) Amyl nitrite inhalant, 0.3 ml (12 ampules) Hydroxocobalamin, 5 g
Personal Protective Equipment	First responders: Level A until decontamination has been completed First receivers: After decontamination, Level C

NERVE AGENTS

Nerve agents are the deadliest chemical agents and difficult to produce. They interact with enzymes in the body that carry signals between nerves and muscles; ultimately, they paralyze the body’s nervous system, leading to respiratory failure and death by asphyxiation. Just a few droplets are capable of killing within minutes if inhaled or within hours if absorbed through the skin.

Nerve agents include:

• Sarin
• Soman
• Tabun
• VX

Sarin is rapidly dispersed by even moderate winds. VX is an oily liquid; it may remain in place for weeks or longer and is readily absorbed through the skin (Huebner, 2021).

NERVE AGENTS

(Huebner, 2021; Williams et al., 2021)
Presentation	Overstimulation and eventual fatigue of the CNS, leading to: Agitation Confusion Unconsciousness Seizures Progressing to failure of the respiratory center in the medulla Overstimulation and eventual fatigue of skeletal muscles, causing: Twitching Fasciculations Progressing to weakness and paralysis Overstimulation of exocrine glands, causing excessive: Tearing Nasal secretions Salivation Bronchial secretions Digestive secretions Diaphoresis Death, usually due to central apnea, but direct paralysis of the diaphragm, bronchospasm, and bronchorrhea can also contribute
Treatment	First responder: Onsite decontamination and antidote administration Atropine administered every 5–10 minutes until secretions begin to dry up Pralidoxime chloride (2-PAM Cl) administered within minutes to a few hours (depending on the agent) to be effective; generally no benefit from more than three injections Military Mark I kit, if available (no longer being manufactured), which is preloaded with 2 mg of atropine and 600 mg of 2-PAM CL First receiver: Supplemental oxygen Cardiac monitoring Early intubation and ventilator support Suctioning for profuse airway secretions
Personal Protective Equipment	First responders: Level A until decontamination has been completed First receivers: After decontamination, Level C

INCAPACITATION/RIOT CONTROL AGENTS

Incapacitation and riot control agents are designed to be nonlethal but can cause injury or death because self-preservation behaviors in affected individuals may be overridden or inhibited. These agents produce temporary physiological or mental effects that render individuals incapable of performing normal activities.

Incapacitation agents and riot control agents are separate classes of nonlethal agents—anticholinergics and lacrimators. Riot control agents differ from incapacitating agents in several ways. They possess a relatively shorter onset and limited duration of action. They induce short-term toxic effects that subside within minutes following termination of exposure. Incapacitating agents are chemicals that produce a disabling condition that persists for hours to days following exposure. These agents induce changes to the central nervous system without lethal effects.

Incapacitating agents include:

• BZ (3-Quinuclidinyl benzilate)

Riot control agents (often incorrectly referred to as tear gas) are dispersed as solid aerosols or as solutions and include:

• CN (chloroacetophenone, also known as Mace)
• CS (Chlorobenzylidene malononitrile, also known as tear gas)
• DM (Adamsite, a vomiting agent)
• OC (Oleoresin capsicum, also known as pepper spray)

INCAPACITATION/RIOT CONTROL AGENTS

(Hostege, 2021; Madsen, 2021; ALA, 2020)
Signs/Symptoms	Incapacitation agents: Dry mouth and skin Dilated pupils Tachycardia Possible hyperthermia CNS effects: Lethargy Visual or auditory hallucinations Confusion Agitation Tremor Ataxia Stupor and coma (may last hours to days, with gradual recovery) Riot control agents: Burning sensation in eyes, mouth, and nose Lacrimation Blurred vision Cough Chest tightness Dysphagia Skin burns Respiratory failure and death is exposed to high dose for prolonged period in enclosed area
Treatment	Incapacitation agents: Decontamination Supportive care, including cooling (if needed) and (rarely) physostigmine Riot control agents: Decontamination No antidote Symptom treatment
Personal Protective Equipment	First responders: Level A until decontamination has been completed First receivers: After decontamination, Level C

Decontamination of Victims of Chemical Agents

Decontamination involves local or spot decontamination of any liquids on the skin, removal of clothing, and copious irrigation of the skin with lukewarm water and, if available, mild soap. Decontamination may be accomplished in the field and also in receiving facilities.

The most important and most effective decontamination of any chemical exposure is done within the first minute or two after exposure.

Field decontamination often consists of setting up stations for disrobing following showering or assisted decontamination. Patients may bypass field decontamination stations, however, and go directly to a medical facility for treatment.

Upon notification of a chemical weapons release, receiving facilities should:

• Secure all entrances and hospital grounds
• Establish a security perimeter
• Set up a decontamination zone outside the clean areas of the facility
• Activate disaster plan
• Establish close communication with local emergency management authorities

Hospital decontamination consists of removal of all clothing and thorough washing of skin and hair with lukewarm water and soap before the patient is brought into the clean area of the emergency department.

Important aspects of planning involved in preparation for decontamination events include:

• Establishment of designated fixed or rapidly deployed decontamination facility
• Properly trained staff in donning and doffing of personal protective equipment
• A triage plan for medical and nonmedical decontamination
• Decontamination procedures that maintain privacy and avoid hypothermia
  (Madsen, 2020)