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Described below are the characteristics of a number of chemical warfare agents that are known to cause hallucinations. All these agents are prohibited under the Chemical Weapons Convention, which came into force in April 1997, well after the end of the war in Bosnia and Hercegovina.

Characteristics of BZ

The best known of such agents is the anticholinergic chemical 3-quinuclidinyl benzilate, known as BZ.147 This benzilate compound is related chemically and pharmacologically to atropine and other widely used anticholinergic drugs. As a result of its properties, it has effects on both the peripheral autonomic and central nervous systems. The effects of BZ have been exhaustively described in a 1963 study by Maj. James S. Ketchum, from which the information in this section is drawn.148

In what is described as “the therapeutic or threshold range,” Ketchum reports the autonomic effects of BZ to consist of the following: “dryness of the mouth, decreased gastric motility, inhibition of sweating, peripheral vasodilation, a slightly increased heart beat and blood pressure, and a mild elevation in body temperature.” Effects on the central nervous system at low doses are limited to “moderate sedation, pupillary dilatation, diminished alertness and mental slowing, dulling of affect, decreased spontaneity, and lowered interest in work and recreational activity.”

As doses are increased, all of these symptoms are intensified and there are, in addition, marked disturbances in the function of the central nervous system. There is a pronounced effect on motor coordination. Affected individuals become less attentive, and the control and direction of thought processes become increasingly difficult. Individuals also encounter a difficulty in retaining new information, and speech and behavior become much more random in nature. Individuals become confused, apprehensive and restless. Eventually, the grasp on reality is lost, and those affected fail to interact with their immediate environment and become stuporous.

According to Ketchum, some of the more detailed effects of BZ are as follows: a rapid heart rate, but one rarely exceeding 150 beats per minute, can occur some three to four hours after exposure. Additional increases in heart rate can be brought about by exercise, but such increases do not exceed the anticipated increase from exercise alone. Both systolic and diastolic blood pressure may be elevated moderately, with peak values reached between five and six hours after exposure to BZ. This increase in blood pressure is largely a secondary consequence of the increased cardiac output associated with a more rapid heart rate.

Flushing of the face and of other areas of the skin is a consistent occurrence, caused probably by a decrease in capillary tone and an increase in blood pressure. A further factor is a reflex which is a compensatory heat-lossmechanism brought about by the rise in temperature caused by inhibition of sweating. A frequent complaint of individuals exposed to BZ is that they feel a sense of weakness, which particularly affects the legs. Tests of muscle strength in these circumstances, however, have demonstrated that the strength itself is only minimally affected.

BZ inhibits secretory activity in the glandular cells concerned with digestion. This results in thick, tenacious and scanty saliva, drying of the mucous membranes of the mouth and throat, and marked pharyngeal discomfort. Swallowing can be painful and speech reduced to a whisper. Tongue and lips can be coated, and breath has a characteristic foul odor. Appetite is reduced, and subjects may refuse all food and fluids for twenty-four hours or more.

Urination may be difficult or impossible for a period of up to sixteen hours following exposure. This is particularly the case where exposure to higher doses has taken place. This occurrence may result in frequent futile attempts to urinate.

Following an incapacitating dose of BZ, Ketchum noted the following effects, occurring in phases: The first phase lasts for a period of between one and four hours and is characterized by feelings of discomfort and apprehension. There is extreme restlessness, with involuntary spasms of the extremities and bird-like flapping of the arms. Errors of speech and scattered moments of confusion may occur. There is a peak period where the affected individual is restless and unable to walk properly (ataxia).

The effects described above can be followed by a second phase, which can last for a period of between four to twelve hours. During this phase, individuals are sedated and can be stuporous and even semi-conscious. The individual may sleep, or appear to sleep, and respond only to direct, and sometimes only to forceful, stimulation. Spontaneous groping or crawling may alternate with lying quietly.

The more extreme of the symptoms associated with exposure to BZ occur in a third phase. These take place approximately twelve hours following exposure. During this phase, hallucinations dominate an individual’s awareness, and real objects and persons are generally ignored or ludicrously misinterpreted.

Complex panoramic hallucinations tend to be most common between approximately twenty-four to forty-eight hours following exposure to doses of the compound above that which has been shown to be effective in some 50 percent of the population tested. Hallucinations may be benign, entertaining, or terrifying. Individuals exposed to BZ are frequently disoriented and unaware of their surroundings. Individuals in the vicinity of those who are affected or exposed may be recognized, or may be mistakenly identified. Vertically-shaped objects may be mistaken for individuals and, in extreme states of confusion, the affected individual may have a conversation with someone who is not physically present but who is perceived to be there through hallucination.

According to Ketchum, recovery from the effects of BZ is gradual. The simpler abilities return initially, while functions which require more complex integration (such as those involving judgment, social awareness, or creative ideas) are the last to be regained.

According to a review of the effects of BZ on 300 subjects, in a research test conducted by the U.S. Chemical Research and Development Laboratories, although subjects can vary in their response to BZ, in general it would appear, according to Ketchum, that there is “little difference how intelligent, adventurous, self-confident or competitive the individual might be; the agent apparently disables the strong and weak impartially and without prejudice.”

If BZ were to be used in a military context, it is highly likely that, if an effective dose of BZ is delivered to the majority of a mixed population, a number of individuals will be exposed to high concentrations. As a result ofthis, there would be some fatalities. The number of fatalities would rise where individuals had other medical conditions, if the area was cold, if these individuals were dehydrated or starved, or if they had been injured in some sort of accident.

According to a U.N. report on an incident in Mozambique in January 1992, soldiers may have been exposed to an agent following an explosion in the air above their troop formation. The symptoms and signs exhibited by the casualties were said to be similar to those which could be caused by exposure to an atropine-like agent, although some of the symptoms may have been due to heat stress as a result of dehydration.149

The symptoms experienced by most of the soldiers exposed in Mozambique are similar to those being documented as being caused by BZ. In the Mozambique incident, some early deaths within one to two hours were reported, with profound muscular weakness occurring within an hour after the attack in some individuals, although there was a delay in onset for several hours in others. Confusion, disorientation, emotional lability (unstability), and irrational behavior were reported to have occurred early in some of the casualties. Some were reported to be confused for a period of several days.150

Characteristics of BZ-Like Compounds

Quinuclidine compounds other than BZ have been studied extensively for their pharmacological properties, and the effects of various chemical substituents on the basic quinuclidine structure have been investigated.151 In the United States a series of compounds with structures like BZ (glycolates) were identified and classified according to differences in speed of onset and relative duration of incapacitation.152

BZ is also classified as a glycolate, with reference to the chemically substituted glycol component of the molecule. Many structural modifications of glycolates have been made, and the structural changes have been correlated with the biological activity of the molecule. Substituents have been examined which will affect the potency of the chemicals (including their ability to sedate) or the nature of the effects, or speed up the onset of the effects without altering the incapacitating properties they possess.153

Glycolates cause incapacitation through interference with muscarinic functions in the nervous system. Such functions include the activation of smooth muscles and salivary glands. Glycolates will also interrupt the central nervous system’s functions mediated by acetylcholine. It is due to these factors that symptoms seen with a range of glycolates are the same as those described in volunteers dosed with BZ.154

Alteration of the chemical structure can affect the onset of symptoms from minutes to hours, as well as the duration of the effects from hours to days. Effects are reversible by treatment with carbamates (such as physostigmine) which are inhibitors of the enzyme acetylcholinesterase.155

Characteristics of LSD 25

Lysergic acid diethylamide (LSD 25) is a widely researched hallucinogen.156 It has also been studied for its military potential.157 It can induce psychosis in people in extremely small amounts. In general, as little as fifty micrograms is an effective dose.158

Initial effects appear within a few minutes following inhalation and within thirty to sixty minutes following ingestion. Maximum effects are reached within two to three hours and gradually subside over the next four to eight hours.159

Signs and symptoms of LSD intoxication include rapid heart rates, sweating palms, pupillary enlargement, nervousness, trembling and spasms, anxiety, euphoria, and inability to relax or sleep. Persons will experience feelings of tension, heightened awareness, exhilaration, kaleidoscopic imagery, emotions of every type, hilarity, and exaltation. Paranoid ideas and more profound states of terror and ecstasy may also occur, especially in highly suggestible individuals. True hallucinations are rare, as is homicidal or suicidal behavior.160

Former JNA chemical warfare officers, both Bosniak and Croatian, have indicated that the JNA had weaponized LSD-25 before the breakup of Yugoslavia in 1991. According to one officer, LSD-25 could be distributed as an aerosol or as a water contaminant.161 Other lysergic acid derivatives have reportedly also been explored for chemical weapons use.162

Other Chemicals

A number of other drugs are considered to be potential military incapacitating agents. These include trytophane, tryptamine, serotonine, piperidine, tetrahydracannabinols, psilocybin, and mescaline (and their numerous analogs).163 Alcohol, amphetamines and opiates can also cause hallucinations.164


Interview Procedure for investigation of an alleged chemical warfare incident

Ensure interviewee is comfortable. Sit next to rather than opposite interviewee. Conduct interview in a quiet place. One person (with interviewer asking questions). Interview subject on their own (if possible). Record presence of others.

A. Interview, incident, relationship to the incident, identity of the person.

1. Place and time of the interview. Interviewer. Interpreter

2. Place and time of the incident (alleged usage)

3. Relationship to the incident: victim, primary witness, secondary source

4. Name

5. Sex. Age at time of interview

6. Current place of residence

7. Nationality

8. Marital status, children

9. Education

10. Occupation/rank at time of interview

11. Current place of work

12. How did interviewee reach interview location?

13. Any acute or chronic illness?

14. Is interviewee taking any medication (taking it at the time, or unable to?)

B. Description of incident in interviewee’s own words (without intervention)

(It can be expected that details will be mentioned regarding date, site, circumstances, weapons, description of the behaviour of others, description of own signs and symptoms, and evolution since the incident. Most probably all of these items will be mixed up, but should be recorded as such).

15. Any previous combat experience

16. Sketch map of the area, indicating important features. If possible, transfer to a standard map

17. What did interviewee see, hear or smell?

- condition of the terrain, and weather (rain, sunshine, cloud cover [0/8 _ 8/8])
- when and how did the incident start?
- aircraft, guns, ammunition, cloud/smoke, colour?
- did you see the opposition, what did he look like? (any protective clothing or equipment?)
- what was your location with regard to the point of impact, downwind area?
- were you directly exposed to the cloud/smoke/aerosol?
- what happened around you? Were others affected? Were animals affected?
- was this the first time you had been affected/exposed in such a way?
- did this experience remind you of anything else?
- did the cloud/smoke/aerosol move? Vertically/horizontally?

D. For a victim: detailed questioning concerning signs and symptoms, and their evolution

18. For each of the following questions, indicate when a condition began after exposure, and for how long it persisted

19. What did you feel after being exposed to the cloud?

20. Were the eyes affected? If so, in what way?

21. Was the nose affected? If so, in what way?

22. Was the mouth and/or throat affected? If so, in what way?

23. Were the ears affected? If so, in what way?

24. Was the neck affected? If so, in what way?

25. Was the chest or breathing affected? If so, in what way?

26. Was the skin affected? Is so, in what way?

27. Were there stomach/abdominal pains, other problems?

28. Was there loss of appetite?

29. Was there fever present?

30. Was there sweating?

31. Was there dizziness?

32. Were there headaches?

33. Was there unconsciousness?

34. Was there behaviour as if drunk? Difficulty walking?

35. Was there disorientation?

36. Were there any convulsions?

37. Was there drowsiness?

38. Was there insomnia?

39. Were there any other symptoms?

40. Did you receive any medical help? If yes, when, of what kind, and for how long? At which hospital did you receive treatment? From which doctor?

41. Did you ever experience similar symptoms? If yes, in what circumstances? (After taking alcohol, drugs, etc...)

42. Did you have enough food/water on the journey?

43. Did you have sufficient sleep, or did you go without sleep? (How long did you sleep at night?)

E. For primary witness: detailed questioning concerning signs, symptoms and evolution of the victims

See questions in section D, but limit them to objective observations:

Be especially aware of, but do not question directly, for reports of the following:

- restlessness
- confusion
- erratic behaviour
- failure to obey orders
- stumbling
- staggering
- vomiting
- delusions
- hallucination

Describe the evolution in time

F. For a secondary witness: some general questioning, in the nature of cross-questioning, to contrast with answers given in sections D and E

See questions under D, but limit to objective observations; what did the victims or witness tell the interviewee regarding signs and symptoms?

G. Other contacts

44. Do you know of anyone else who was affected during the incident?

45. Have you talked to them about the incident?

46. Have they been interviewed?

47. Will you be available for interviews in the future?

48. Thank you for your help

H. Overall assessment of the interview and of the credibility of the respondent

49. How confident are you of the reliability of the testimony of the respondent; and on what grounds?

50. How certain or uncertain would you say the respondent was in providing the different parts of the testimony?

51. What are the questions that were irrelevant in this and previous interviews; and what are the questions that, on the basis of what has been reported spontaneously, should be added?

52. What items of significance emerged which should be confirmed (where possible) in later interviews?

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147 Most of the literature on the effects of BZ on humans is either classified in U.S. military archives, or available in some recent declassified reviews. These reviews discuss BZ’s disturbing behavioral effect on animals and its ability to accumulate in tissues such as the heart, lung, and brain for many hours following administration of the chemical to rodents. See W. F. Uliu, et al., “Effects of 3-Quinuclidinyl Benzilate on Fixed-Ratio Responding and Open Field Behavior in the Rat,” Psychopharmacology, vol. 80 (1983), pp. 10-13; and J. Ishizaki, et al., “A Physiologically Based Pharmacokinetics Model for (-)-Quinuclidinyl Benzylate Using Non-Linear Irreversible Tissue Binding Parameters in Rats,” Drug Metabolism and Disposition, vol. 20 (1992), pp. 485-89. Requests by Human Rights Watch to the U.S. Army for the release under the Freedom of Information Act of two documents on the effects of BZ under field conditions were denied. These documents were: “The Human Effect of BZ Disseminated under Field Conditions” (November 1967), and “Final Estimates of ICt50 for Agent BZ under Field Conditions as Simulated during Project DORK” (June 1965). Letter from Patrick R. Sheldon, Chief Counsel, U.S. Army Chemical and Biological Defense Command, Department of the Army, to Human Rights Watch, June 17, 1997.

148 Maj. James S. Ketchum, “The Human Assessment of BZ: CRDL Technical Memorandum 20-29” (Edgewood Arsenal, Maryland: U.S. Army Chemical Research and Development Laboratories, 1963).

149 United Nations, “Report of the Investigations into the Allegations of the Use of Chemical Warfare in Mozambique,” s/24065 (New York: United Nations, January 1993).

150 Ibid.

151 M. D. Mashkovsky and L. N. Yakhontov, “Relationships Between the Chemical Structure and Pharmacological Activity in a Series of Synthetic Quinuclidine Derivatives,” Progress in Drug Research, vol. 13 (1969), pp. 293-339.

152 Herbert S. Aaron, Chemical Warfare Agents: A Historical Update from an American Perspective (Aberdeen Proving Ground, MD: U.S. Army Chemical and Biological Defense Agency, 1993), p. 18, citing National Research Council, Possible Long Term Health Effects of Short Term Exposure to Chemical Agents, vol. I (Washington, DC: National Academy Press, 1982), p. 72.

153 Ibid.

154 Department of the Army, Handbook of the Medical Aspects of NBC Defensive Operations, FM8-9 (Washington, D.C., February 1996), available at

155 Departments of the Army, the Navy, and the Air Force, NATO Handbook, part III, p. 6-3.

156 See H. B. Linton and R. J. Langs, “Subjective Reactions to Lysergic Acid Diethyl Amide (LSD-25),” Archives of General Psychiatry, vol. 6 (1962), pp. 36-52; J. O. Cole and M. M. Katz, “The Psychotomemtic Drugs,” Journal of the American Medical Association, vol. 187 (1964), pp. 758-61; N. A. Bercel, et al., “Model Psychoses Induced by LSD-25 in Normals,” American Medical Association Archives of Neurology and Psychiatry, vol. 75 (1956), pp. 612-18; and T. Greiner, et al., “Psychopathology and Psychophysiology of Minimal LSD-25 Dosage,” American Medical Association Archives of Neurology and Psychiatry, vol. 79 (1958), pp. 208-10.

157 See Siegfried Frank, Manual of Military Chemistry, Volume 1: Chemistry of Chemical Warfare Agents (East Berlin: National People’s Army of the German Democratic Republic, 1967), pp. 301-03 (translated from German by the U.S. Foreign Broadcast Information Service); and Departments of the Army, the Navy, and the Air Force, NATO Handbook, part III, pp. 6-5 to 6-6.

158 Departments of the Army, the Navy, and the Air Force, NATO Handbook, p. 6-5.

159 Ibid.

160 Ibid.

161 Human Rights Watch interviews with two former JNA chemical weapons officers, Croatia and Bosnia and Hercegovina, February-March 1996. See also Human Rights Watch Arms Project, “Clouds of War.”

162 Frank, Manual of Military Chemistry, p. 301.

163 Ibid., pp. 298-311, and Departments of the Army, the Navy, and the Air Force, NATO Handbook, p. 6-5.

164 See E. Bruera, “Organic Hallucinosis in Patients Receiving High Doses of Opiates for Cancer Pain,” Pain, vol. 48 (1992), pp. 397-99.

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