1

Chemical Warfare:History and Chemistry

Stephen L. Morgan

ProfessorDepartment of Chemistry & Biochemistry

The University of South CarolinaColumbia, SC 29208

Email: morgan@mail.chem.sc.eduURL: http://www.chem.sc.edu/faculty/morgan

Lecture material URL: http://www.chem.sc.edu/faculty/morgan/cw

Chemical and Biological Warfare (CBW)

Compared to other “weapons of mass destruction”, CBW has seen very little use.

The potential threat of CBW is terrifying:

…blinded, disoriented, clutching your chest, gasping for breath, drowning in mucus fluids pouring from the lungs, choking to death…

CBW is silent, invisible, pervasive, and deadly. You may not be able to hide from it.

Chemical warfare (CW) agents use poisons that kill, injure, or incapacitate. CW agents can be gases or liquids or, more commonly, dispersed as aerosols.

Biological warfare (BW) agents use living bacteria (e.g., Bacillus anthracis, the causative agent of anthrax) or viruses (e.g., Variolae, the virus that causes smallpox).

2

CW agent UseCW use in the trenches of World War I allowed attacks to break through fortifications. Heavier-than-air gases would fill the trenches and tunnels, rendering them useless for defense.

Modern precision-guided conventional weapons render this classical motive for CW obsolete.

“Suiting up” an army in CBW protective gear is expensive, time-consuming, degrades communications and fighting ability, and causes panic and chaos. Creating massive casualties requiring medical aid further impairs effectiveness by spreading uncertainty and, ultimately, fear. CBW is the ultimate terror weapon.

Another argument: “If the enemy has it, we must have it.”

CW (or BW) agents are said to have a large “footprint” and are cheaper than conventional weapons.

Chemical weapons are a kind of “poor man’s atomic bomb.”

Iranian President Ali Akbar Hashemi, 1988,at the end of Iran’s war with Iraq.

3

Routes of entry for CW agents

• inhalation through lungs

• ingestion by mouth

• injection through puncture wound

• absorption on skin

Classes of CW Agents

• Choking gases and lung irritants)• Blister agents (vesicants) • Blood agents • Nerve agents• Incapacitants and psychoactive chemicals • Harassing or riot-control agents (RCAs)

and vomiting agents• Herbicides• Napalm • Obscurant smoke and masking agents

4

Choking gases and lung irritantsChoking gases and lung irritants

CW agents that irritate the respiratory system causing formationof water in the lungs, resulting in death from lack of oxygen

Chlorine (Cl2): “A new form of warfare”Use: by Germany against Allied troops on 22 April 1915 at 5 pm near Ypres, Belgium.

Result: 5,000 dead, 10,000 wounded.

Logistics: 5,730 90-lb cylinders buried in concealment along a 6-km front; 160 tons of gas were manually released when the wind was favorable.

5

Description and effects of chlorine

Description: Greenish yellow gas; amber liquid. Odor is suffocating, pungent, and irritating.

Health effects: Causes burning of nose and mouth with rhinorrhea, respiratory distress with coughing fits, choking, wheezing, rales, retching, hemoptysis, substernal pain, dyspnea, and cyanosis. Strips and inflames the mucous lining of the bronchial tubes and lungs,allowing fluid to enter the lungs from the bloodstream. May cause bronchitis, progressing to pulmonary edema and occasional pneumonitis. Causes Chronic respiratory and pulmonary dysfunctions.

Other symptoms include salivation, anxiety, sneezing.. Pallor or redness of the face, weakness, hoarseness, headache, dizziness, and general excitement and restlessness. Massive inhalation may alos cause death by cardiac arrest. May irritate skin and cause burning and pricking sensations, inflammation, and blisters.

Oil on canvas 231 × 611.1Imperial War Museum, London

John Singer Sargent, Gassed (Aug. 1918)

6

Phosgene (carbonyl chloride, COCl2)

Use: At 5:30 am on 19 December 1915, the Germans attacked at Ypres (again) using phosgene in artillery shells.

Results: Panic and disruption as men were caught unawares. 1,069 men gassed; 116 dead.

At the Somme in June 1916, the Allies used both chlorine and phosgene: men, vegetation, insects, and animals were wiped out. Over the next 19 months, the British discharged over 1,500 tons of phosgene.

Gassed and Wounded, OilEric Henri Kennington (1888-1960), English

7

Other choking gases

Liquid at room temperature,thus persistent, WW1

Discovered in 1848, used by Russians in WW1, attacks rubber, dual-use as odor in pesticides

Volatile, fast acting, WW1

Industrial use, gas decomposition product from Teflon®; 10× more lethal than phosgene; latency 1-4 hr before pulmonary edema; prepared by Russia as CW

diphosgene(trichloromethyl chloroformate )

chloropicrin (trichloronitromethane)

ethyldichloroarsine(DICK)

perfluoroisobutylene(PFIB)

Blister agents (vesicants)Blister agents (vesicants)

CW agents that affect eyes, lungs, and skin, causing formation of large blisters

8

Mustard(bis-(2-chloroethyl)sulphide, (ClCH2CH2)2S )

Use: On 12 July 1917, about 10 pm, at Ypres, Belgium, the Germans shelled the British with 77 and 105 mm gas shells.

Result: Initial effect was just sneezing; within hours eye irritation, vomiting, and blisters appeared.

Also called Lost,Yperite, H or HD

Gas attack by artillery in WW1

Description and effects of mustardDescription: A yellow-brown liquid in crude preparation; colorless in pure form. An oily unpleasant smell like mustard, tasting like garlic (perhaps due to impurities).

Health effects: On skin contact, the fat-soluble liquid penetrates the skin and destroys interior tissue in a delayed reaction (up to 24 hr), causing blisters that take a long time to heal. Death may occur from toxic shock within 24 hr of massive exposure.

9

Other blister agents

nitrogen mustard

Lewisite(2-chlorovinyl dichloroarsine)

phosgene oxime

phenyldichloroarsine(PD)

Oily persistent liquid, more toxic than sulfur mustard, some medical applications.

The “dew of death,” prepared in 1918 by W. Lee Lewis (Catholic Univ.) for WW1; nonflammable; fast acting blistering.

“Nettle gas” or “Red cross” (WW2): acute damage to lungs, eyes, and skin; chronic systemic effects.

Liquid, persistent, extremely irritating to nose and throat, also a vomiting agent; developed as CW by Haber.

Growing use of CW in WWI

Year Amount of gas discharged, tons1915 3,8701916 16,5351917 38,6351918 65,160

J. B. S. Haldane, Callinicus⎯A Defence of Chemical Warfare,Kegan Paul: London, 1925, pp. 28-38.

10

In no future war will the military be able to ignore poison gas.

It is a higher form of killing.

Professor Fritz Haber, pioneer of gas warfare,on receiving the Nobel Prize for chemistry, 1919.

Blood agentsBlood agents

CW agents that interfere with the body’s ability to transport oxygen in the blood stream

11

Blood agentsPoisons that block oxygen use or uptake from the blood, causing asphyxiation.

Hydrogen cyanide (HCN, prussic acid): Liquid at room temperature, but evaporates rapidly. Used in Zyklon B made by IG Farben for use in German WW2 extermination camps. Unstable due to rapid polymerization and thus considered unsuited today for CW.

Unconfirmed reports: 1980s, HCN used by Syria against uprising in Hama; 1988, Iraqi attack on Kurdish town of Halabja; in Shahabad, Iran, during the Iran-Iraq war.

Japanese WW2 HCN grenade

Other blood agents

cyanogen chloride (CK)

arsine (AsH3)

carbon monoxide(CO)

hydrogen sulfide(H2S)

Toxic flammable gas, destroys red blood cells, widespread organ injury; powerful reducing agent, strong affinity for hemoglobin; hemolysis of red blood cells causes renal failure.

Volatile, but less flammable than HCN

Common pollutant, by product of heating systems; binds to hemoglobin with an affinity 250-300× that of oxygen; victims die by asphyxiation and take on a cherry red skin color.

More toxic than HCN, used in WW1; by-product of decaying organic matter or volcanic activity; 1997: planned use in a diversionary explosion in white supremacist robbery plot foiled by the FBI.

12

Nerve agentsNerve agents

CW agents that interfere with the body’s nervous system by disrupting the acetyl cholinesterase process

Nerve agentsFirst developed by Gerhard Schrader of IG Farben in 1936 as an outgrowth of organophosphate pesticide development. Routes: inhalation and skin contact.

Health effects: Nerve agents act by paralyzing the respiratory muscles by attacking acetyl cholinesterase which blocks muscle relaxation; extreme muscle twitching, fast breathing, followed by bronchoconstriction result. Severe fatigue and mucosal and salivary excretion, stopping breathing.

13

G-series nerve agents

Tabun(ethyl NN-dimethyl-

phosphoramidocyanidate, GA)

Sarin(isopropyl methylphosphono-

fluoridate, GB)

Soman(1,2,2,-trimethylpropyl

methylphosphonefluoridate, GD)

First nerve agent discovered, colorless liquid which turns to vapor at room temperature.

Non-persistent, causes death in 1-2 min through skin, 15 min inhaled.

Semi-persistent, primary agent for Soviets, 3× more toxic as tabun.

V-series nerve agents

VXo-ethyl S-2-

diisiopropylaminoethyl methylphosphonothiolate

Health effects: The V-series agents (VE, VG, VM, and VX) are more toxic than the G-series. 10-15 mg of VX, less than a drop, in contact with skin will kill a man of average weight unless medical attention is provided; takes several hours for effects.

Delivery: These agents are also more persistent than the G-series: less of vapor hazard, more of skin hazard. High persistence means they can be used to contaminate (or in military jargon, “slime”) surfaces (roads, equipment, etc.) to harass and immobilize.

14

‘Taliban, al Qaeda might have nerve gas,’ The State, pA7, 1/23/02

Incapacitants and psychoactive chemicals

CW agents that can incapacitate, disorient, or paralyze

15

Incapacitants - 1Desired characteristics: effects will endure over time (hours, days); not endanger life or cause permanent injury; recovery not require medical attention; agents must be deliverable, potent, and easy to store.

Belladonna (glycolate alkaloids such as atropine): derived from belladonna, a poisonous plant of the nightshade family, these poisons have been known since 200 BC. Pupil dilation, dryness, fever, and sight impairment are typical symptoms.

3-quinuclidinyl benzilate (BZ): Belladonna-based incapacitant that attacks the CNS, depressing the nervous system, causing hallucinations; designed to be delivered in aerosol form. Manufactured at Pine Bluff Arsenal (AR); most stocks destroyed in the 1980’s. 1988: alleged report of use against Bosnian refuges.

Incapacitants - 2

Ergot and lysergic acid diethylamide (LSD)

1951, France: The calls from stricken new patients kept flooding in. By Monday, August 14, the town's hospital was swamped. Seventy homes had also been turned into emergency wards. That first night the first victim died in agonizing convulsions. Raving patients were held in their beds or escaped from their homes, mad, frantic, to run in the streets. The terror grew as the news broke that a demented eleven-year old boy had tried to strangle his own mother. The mood of the people and the atmosphere of the place began to resemble that of a plague-swept town of the Middle Ages. ...Finally, the chief toxicologist of Marseilles sent his report to Pont-St.-Esprit and the anxious nation. The bread contained twenty alkaloid poisons, three of them Virulent, and all came from the same source. The poisons could be found in fungus growth that changed normal kernels of rye to purplish cockspurs called ergot.

Carefoot, G. L.; Sprott, E. R. Famine on the Wind: Plant Diseases and Human History, Angus and Robertson: London, 1967; pp. 17-18.

16

Harassing or riot-control agents (RCAs) and vomiting agents

CW agents used to combat public disturbances as a non-lethal means to disperse unruly crowds

Description and effects of RCAs

• Some compounds are lacrimators (tear-producing agents); some are sternutators (sneezing agents). Most are not lethal unless ingested in high doses. Vomiting agents can cause death in constrained spaces or if the victim chokes.

• Tear gases or RCAs irritate the eyes and mucosal tissues of the nose and mouth, causing extreme discomfort.

• Debate has continued about the ethics of using riot-control agents in warfare. Current international agreements prohibit use of RCAsin wartime.

17

RCA examplesethylbromoacetate

chloroacetone

Xylyl bromide(T-stoff)

Acrolein

Strong lacrimator, used by the French in WW1 for both rifle grenades and regular grenades.

Used for French rifle grenades in WW1.

The first CW agent produced by Germany in WW1; corrodes most metals, requires lead canisters for storage; less toxic but more powerful lacrimator than ethylbromoacetate. Iodine analog also used.

Relatively toxic and potent lacrimator made form glycerine (cheaper); however, produces acrylic acid on exposure to air which quickly polymerizes to inert gel. Stability prevents it being used as an effective CW agent.

RCA examples (continued)Bromobenzyl cyanide

(CA, camite)

chloroacetophenone(CN)

Synthesized by halogenating phenyl cyanide in 1914. First used by the French in July 1918; manufactured in quantity by the U.S. starting in 1918. Corrodes metals, prone to decomposition, and heat sensitive; requires special handling and storage.

CN is one of the most potent lacrimators known. Difficult to manufacture, not used in WW1. Japan may have bee the first to use CN in Taiwan in 1930.

Mace®, Methylchloroform chloro acetone, a related compound is sold commercially as a liquid spray to use against an attacker. Pepper spray, made from capsaicin from chili peppers, is largely replacing CN.

18

RCA examples (continued)

o-chlorobenzylidenemalononitrile (CS)

CS is now the tear gas of choice in the U.S. Delivered as 3-10 µ microencapsulated particles in aerosols, or as a thermal grenade producing CS fumes.

“Typically, men leave the exposure with tears, nasal secretions, and saliva pouring out, and towels rather than handkerchiefs are needed to cope with the fluids. In 5-15 minutes, the irritation ceases.”

Possible Long-term Health Effects of Short-term Exposure to Chemical Agents, Volume 2. Cholinesterase Reactivators, Psychochemicals, and Irritants and

Vesicants, National Research Council: Washington, D.C., 1984; p. 159.

HerbicidesCommon agents include:

Herbicide Compound

Paraquat bipyridylium

Agent White picloram, 2,4-dichlorophenoxyacetic acid

Agent Orange 2,4,5-trichlorophenoxyacetic acid and 2,4-D(defoliant used in Vietnam)

Agent Blue dimethyl arsenic acid

19

2,3,7,8-tetrachlorodibenzo-p-dioxin(dioxin or TCDD)

Health effects: acute and chronic: distorted perceptions, changes in motor activity, nausea, respiratory irritation, CNS depression, liver, kidney and lung damage, severe eye and skin irritation. Highly toxic.

Napalm

Obscurant smoke

Masking agents

Early incendiaries were “Jellied” mixtures of gasoline and rubber; the M-47 bomb was gasoline jelly mixed with white phosphorus for ignition. NAPALM is a mixture of aluminum soaps of naphthenic and coconut fatty acids and palm oil.

In WW1, white phosphorus was often used to generate smoke, but its toxicity has led to replacement by titanium tetrachloride for obscurant smoke.

Malodorous compounds are often used to mask the presence of other gases or to force the enemy to suit up when no CW is present.

Mercaptans Skatole (rotting offal)

3-methyl-1-butanethiol (skunk)

20

Steps to chemical warfare

1. Acquisition of CW materials

2. Production of CW agents

3. Delivery of CW weapons

Acquisition of CW materials• Develop from raw materials (or precursors), purchase outright, or combine “home-grown” with “store-bought.”

• Many precursors to CW weapons are materials with legitimate commercial uses:

Compound Commercial use CW use

Thiodiglycol Plastics, textile dyes, ink MustardPhosphorus trichloride Plasticizers, insecticides G-seriesSodium cyanide Dyes, pigments, metal hardening GA, AC, CKMethylphosphonic difluoride Organic synthesis VX, GB, GD

Crody, E.; Perez-Armendariz, C.; Hart, J. Chemical and Biological Warfare, Springer-Verlag New York Inc.: New York, 2002.

21

Production of CW agents• Synthesis in small batch quantities in a pilot plant to solve technical difficulties in chemistry, scale-up, handling.

• Use of standard chemical engineering equipment (reactors, distillations apparatus, heat exchangers, pumps, valves, filters, etc.). Obtaining and maintaining this equipment may be problematic.

• Specialized equipment (e.g., glass lines or steel reactors) may be needed to handle corrosives.

• Making the product into a suitable form to use as a weapon (“weaponizing”) usually requires some technical expertise. Issues include: design of unitary or binary CWs; stability; handling; storage; dissemination as liquid, powder, spray, or aerosol; dispersal; thermal and shock lability.

Delivery of CW agentsThe effectiveness of CW agents is influenced by a combination

of the choices made in delivery and environmental conditions.

• CW delivery:

point source with munitions;

line source with sprayer.

• Form:

Liquid, aerosol, or vapor.

• Atmospheric conditions:

temperature (and patterns of temperature), time of day;

wind, sun, rain, altitude.

22

Iraq CW Program 1988-1991In possession: 1,000-4,000 tons mustard gas and nerve agents: tabun(GA), sarin (GB), GF (cyclosarin).

In development: soman (GD), persistent nerve agent VX, hallucinogen agent BZ.

Delivery: Soviet-purchased 122-mm multiple rocket launchers, helicopter-launched 90-mm rockets with chemical warheads, 250/500 kg aerial chemical bombs, chemical projectiles for 155-mm artillery guns, Scud chemical warheads. Monthly production : 150 tons mustard, 5-10 tons tabun, 20 tons sabin.

Mauoroni, A. J. Chemical-Biological Defense: U.S. Military Policies and Decisions in the Gulf War, Praeger Publishers: Westport, CT, 1998.

CW terrorism1974: Muharem Kerbegovic was arrested in Los Angeles after mailing toxic material to a Justice of the Supreme Court and threatening to kill the president with nerve gas1991: German authorities thwarted a neo-Nazi plot to pump hydrogen cyanide into a synagogue.1992: the FBI arrested two members of the Patriots Council in Minnesota for possession of less than one gram of ricin, under the Biological Weapons Anti-Terrorism Act of 1989.1993: First World Trade Center Bombing led by Ramsi Yousef. The use of cyanide was considered, but delivery was considered too expensive.1994: Aum Shinrikyo, an apocalyptic religious cult based in Japan, used a refrigerated truck to spray sarin on several magistrates who were to rule against them in a legal dispute. The judges survived, 7 bystanders were killed, and 144 were seriously injured.1995: Attack on Tokyo subway by Aum Shinrikyo used sarin. 12 people killed, 1,000 injured in 16 stations. Would have been worse if they had not diluted their sarin stock with acetonitrile.

23

The future threat

Comment 1:

Many of the chemical weapons discussed here are considered obsolete for military purposes.

Many of them require some expertise and cost to make, produce in quantity, handle correctly, “weaponize”, and deliver.

CBWs are simply not as available as bullets and bombs.

The future threat

Comment 2:

Chemical or biological weapons provide more “bang for the buck,” killing their victims with less cost than bullets or bombs.

24

The future threatComment 3:

The level of knowledge required to manufacture chemical weapons is on the order of a competent organic chemistry graduate student—much less knowledge than required for biological weapons.

Most of the starting materials and equipment can be commercially purchased without notice or alarm.

“… We [have] the ability to make and use chemicals and poisonous gas. And these gases and poisons are made from the simplest ingredients, which are available in the pharmacies; and we could, as well,

smuggle them from one country to another as needed. And this is for use against vital institutions

and residential populations and drinking water sources and others…”

Ramsi Yousef, , 1995, convicted terrorist bomber for first World Trade Center bombing

25

The future threatComment 4:

The large amounts of industrial chemicals manufactured and shipped (e.g., chlorine) offer themselves as low-tech weapons of opportunity and terror.

“Obsolete” for the strategic or tactical military operations is not the same as unusable for terrorism.

The events of 11 September 2001 show that even “ordinary” items of our high-tech world can be transformed into weapons.