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Table 3: Medical Characteristics of Chemical Warfare Agents1

Click here to see the toxicity of chemical and biological agents.


Blister Agents

Agents that cause blisters on skin and damage the respiratory tract, mucous membranes, and eyes.
Name/Symbol
Means of Exposure
Lethal Dosage2
Rate of Action3
Effects
Antidotes/ Methods of Treatment
Sulfur Mustard (HD) Skin contact and/or inhalation Via inhalation: 1,500 LCt50

Via skin exposure: 4,500 LD50

Delayed (tissue damage occurs within minutes of contact, but clinical effects are not immediately evident)

Effects manifested 2 to 24 hours after exposure

Pain is not immediate.

Topical effects occur on the skin (blisters), in airways (coughing, lesions, in rare cases resulting in respiratory failure) and in the eyes (itchiness, burning sensation, possible cornea damage)

Nausea and vomiting can also result

Thorough decontamination using water

Prevention of infection using antibiotics

Application of lotions/ointments to soothe blisters

Mustard has no known antidote

British-Anti-Lewisite can mitigate some systemic effects of lewisite, though it can itself cause some toxicity.

Lewisite (L) Skin contact and/or inhalation Via inhalation: 1,300 LCt50

Via skin exposure: greater than 4,500 LD50

Rapid

Pain and irritation occur immediately
Effects are similar to mustard: skin blistering, burning/watery/swollen eyes, upper airway irritation, systemic blood poisoning
Nitrogen Mustard (HN-3)4 Skin contact and/or inhalation Via inhalation: 1,500 LCt50

Via skin exposure: 4,500 LD50

Rapid

Rash occurs within one hour; blistering occurs between 6 to12 hours after exposure

Skin blistering, respiratory tract damage
Mustard-Lewisite Skin contact and/or inhalation Via inhalation: 1,500 LCt50

Via skin exposure: 10,000 LCt50

Rapid

Stinging sensation occurs immediately; blisters follow hours later

Skin blistering, burning in the eyes, inflamation of respiratory tract
Phosgene-oxime (CX) Skin contact and/or inhalation Via inhalation: 3,200 LCt50

Via skin exposure:
25 LD50

Rapid Extremely irritating to eyes, skin, and upper respiratory system

Nerve Agents

Lethal substances that disable enzymes responsible for the transmission of nerve impulses.
Name/Symbol
Means of Exposure
Lethal Dosage2
Rate of Action3
Effects
Antidotes/ Methods of Treatment
Tabun (GA) Skin contact and/or inhalation Via inhalation: 400 LCt50

Via skin exposure: 1,000 LD50

Very rapid

Incapacitating effects occur within 1 to 10 minutes; lethal effects occur within 10 to 15 minutes

Effects seen in eyes (contraction of pupils, pain, dim or blurred vision), nose (runny nose), and airways (chest tightness)

Nausea and vomiting also possible

Twitching/convulsions result when skeletal muscle reached

Fluctuations in heart rate

Loss of consciousness and seizure activity can occur within one minute of exposue in cases of exposure to high concentration of agent

Eventual paralysis, death

4 steps to management of exposure to nerve agents:
  • decontamination
  • ventilation
  • antidotes
  • supportive therapy

Therapeutic drug options:

  • Atropine and Pralidoxime Chloride (autoinjectors packaged together in kits provided to military personnel)

  • Diazepam (anticonvulsant drug)

Pretreatment option:

  • Pyridostigmine (can increase the lethal dose threshold significantly if ingested prior to exposure and if paired with traditional therapeutic options)

Sarin (GB) Skin contact and/or inhalation Via inhalation: 100 LCt50

Via skin exposure: 1,700 LD50

Very rapid

Incapacitating effects occur within 1 to 10 minutes; lethal effects occur within 2 to 15 minutes

Soman (GD) Skin contact and/or inhalation Via inhalation: 70 LCt50

Via skin exposure:
50 LD50

Very rapid

Incapacitating effects occur within 1 to 10 minutes; lethal effects occur within 1 to 15 minutes

VX Skin contact and/or inhalation Via inhalation: 50 LCt50

Via skin exposure:
10 LD50

Rapid

Incapacitating effects occur within 1 to 10 minutes; lethal effects occur within 4 to 42 hours

Novichok 5 agents

Novichok 5 estimated to exceed effectiveness of VX by 5 to 8 times

Novichok 7 estimated to exceed effectiveness of soman by 10 times.

Very rapid

Assumed to be similar to the effects of other nerve agents listed above Assumed to be similar to treatment methods for other nerve agents listed above

Choking Agents

Substances that damage respiratory tract, causing extensive fluid build-up in the lungs.
Name/Symbol
Means of Exposure
Lethal Dosage2
Rate of Action3
Effects
Antidotes/ Methods of Treatment
Chlorine Inhalation 3,000
LCt50
Rapid

Lethal effects manifest 30 minutes after exposure

Shortness of breath, irritation of mucous membranes; coughing; tightness of chest

Culminates in fluid build-up in lungs leading to fatal choking

No antidote once exposed

Individuals should don gas masks and other protective gear to prevent inhalation

Medical responses include:

  • Relocation to decontaminated environment
  • Enforced rest
  • Management of secretions in airways
  • Oxygen therapy
  • Prevention/treatment of pulmonary edema
Phosgene (CG) Inhalation 3,200 LCt50 Delayed

Asymptomatic period can last up to 24 hours

Diphosgene (DP) Inhalation 3,200 LCt50 Delayed

Incapacitating and lethal effects felt after 3 or more hours

Chloropicrin (PS) Inhalation 20,000
LCt50
Variable

Produces tears in seconds; lethal effects felt after 10 minutes

Vomiting, fluid build-up in lungs

Blood Agents

Agents that interfere with the absorption of oxygen into the bloodstream.
Name/Symbol
Means of Exposure
Lethal Dosage2
Rate of Action3
Effects
Antidotes/ Methods of Treatment
Hydrogen Cyanide (AC) Inhalation 2,000 to 5,000
LCt50
Rapid

Exposure to low concentrations causes symptoms in 1 or more hours

Exposure to high concentrations causes sudden unconsciousness

Agents inhibit cell respiration; heart and central nervous system are susceptible

Cyanogen Chloride also greatly irritates eyes and lungs

In moderate cases:

  • vomiting
  • dizziness
  • deeper, more rapid breathing

In severe cases:

  • convulsions
  • respiratory failure
  • sudden loss of consciousness leading to death
Agents are highly volatile; flush eyes with water; remove contaminated clothing; rinse exposed skin with water

Antidotes: intravenous administration of sodium nitrite and sodium thiosulfate for detoxification purposes (i.e., to assist body's ability to excrete cyanide from system)

Pretreatment under development in the United Kingdom

Cyanogen Chloride (CK) Inhalation 11,000
LCt50
Rapid

Lethal concentration produces effects within 15 seconds of exposure; death following within 6 to 8 minutes


Riot Control (Incapacitating) Agents6

Susbstances that rapidly produce temporary disabling effects.
Name/Symbol
Means of Exposure
Lethal Dosage2
Rate of Action3
Effects
Antidotes/ Methods of Treatment
Tear Agent 2 (CN) Inhalation 7,000
LCt50
Rapid Instant pain in eyes and nose; tearing induced; coughing; chest tightness; vomiting if high doses are swallowed or if individual is especially sensitive Relocate to fresh air

Thorough washing of exposed eyes and skin with water

Effects generally dissipate within 15 to 30 minutes of departure from contaminated area

Tear Agent O (CS) Inhalation 61,000
LCt50
Rapid
Psychedelic Agent 3 (BZ) Inhalation N/A Rapid

Effects felt within 30 minutes

Induces altered states of consciousness, including hallucinations, stupor, forgetfulness, confusion



1. Sources: Central Intelligence Agency, The Chemical and Biological Warfare Threat (Washington, D.C.: Central Intelligence Agency, 1995); Office of Technology Assessment, Proliferation of Weapons of Mass Destruction: Assessing the Risks, OTA-ISC-559 (Washington, D.C.: Government Printing Office, 1993); Valerie Adams, Chemical Warfare, Chemical Disarmament (Indianapolis: Indiana University Press, 1990); Stockholm International Peace Research Institute, The Problem of Chemical and Biological Warfare Volume I The Rise of CB Weapons (New York: Humanities Press, 1971); Chemical Weapons Convention Verification: Handbook on Scheduled Chemicals (August 1993); Gordon Burck and Charles Floweree, International Handbook on Chemical Weapons Proliferation (New York: Greenwood Press, 1991); U.S. Army Center for Health Promotion and Medicine, "Detailed Chemical Fact Sheets," Office to the Deputy for Technical Services, last updated 23 July 1998 [http://chppm-www.apgea.army.mil/dts/dtchemfs.htm]; Iraqi Weapons of Mass Destruction Programs (Washington, D.C.: Central Intelligence Agency, February 1998); Edward M. Spiers, Chemical Warfare (Urbana: University of Illinois Press, 1986); Robert E. Boyle, U.S. Chemical Warfare: A Historical Perspective, (Albuquerque, N.M.: Sandia National Laboratories, August 1998)

2. Approximate median lethal dosage of inhaled airborne agent given in LCt 50 (milligrams per minute per cubic meter, or mg-min/m3), also referred to as lethal concentration time. Approximate median lethal dosage of skin-absorbed agent given in LD 50 (milligrams of agent per kilogram of body weight, or mg agent/kg body weight). The lower the number, the more lethal the agent. (Burck and Floweree)

3. Rate of action refers to how quickly incapacitating effects are felt.

4. In total, three nitrogen mustard agents were developed. The first, HN-1, explored in the late 1920s and early 1930s, was originally designed as a pharmaceutical product. HN-2 followed as a military agent, but later transitioned into the pharmeutical realm. HN-3 was the last of the nitrogen mustards to be developed. These charts focus on HN-3 because its blistering capabilities approach those of sulfur mustard (HD).

5. For more information regarding novichok agents, refer to Vil Mirzayanov's "Dismantling the Soviet/Russian Chemical Weapons Complex: An Insider's View," Chemical Weapons Disarmament in Russia: Problems and Prospects (Washington, D.C.: Henry L. Stimson Center, 1995).

6. Riot control agents listed are a partial representation of existing incapacitating agents. Other agents currently stockpiled around the world for law enforcement purposes can cause vomiting and irritation of the skin, among other symptoms.


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