BHARAT RAKSHAK MONITOR - Volume 5(3) November-December 2002

Utility of Chemical Agents in Anti-Terrorist Operations

Shivshankar Sastry and Jagan Mohan

Introduction

On Wednesday the 23^rd October 2002 about 50-armed Islamist Chechen terrorists forced their way into a Moscow theater. The theatre was screening a musical and there were about 800 people present there. These people were taken hostage by the terrorists. The terrorists threatened to the theater up, and kill all the hostages. The also claimed that they had explosives strapped to their bodies and would blow themselves up if there was any attempt made to rescue the hostages. (1,4)

The standoff, and the hostages’ ordeal, continued for three days. As the world watched through the eyes of the media parked outside the theater, hopes for a settlement without massive bloodshed were fading. Russian authorities however sprang a surprise on the terrorists and the world. In a 'first time ever' action, seemingly taken straight out of science fiction books, Russian security forces used a mystery "knockout gas" to incapacitate the terrorists and hostages alike, stormed the theater and killed all the terrorists and rescued over 750 hostages (2,3). Tragically however the rescue came at an extremely high cost - with 117 (4) to 119 (5) hostages having died without injury from causes that have been allegedly attributed to the use of a chemical agent to overpower the terrorists and their hostages.

The purpose of this paper is to examine the role of chemical agents in reversibly and safely overpowering groups of people in enclosed areas. Some technical aspects regarding the use of these agents will be discussed, along with the particular difficulties and dangers and a description of known chemical agents that could be used in such situations. Chemical agents designed to cause death will not be discussed. The two chemical agents currently thought to have been employed by the Russian conflict resolution team in this hostage crisis, Fentanyl(4,6) and Halothane(5,6) are also described.

General Technical Considerations

The ideal "knockout gas" for use in hostage situations should have the following characteristics:

· it should be capable of passing into the blood from the air in the lungs and then pass from the blood into the brain,

· it should be colorless and odorless so as not to cause suspicion or panic,

· the agent should be easy to disperse in large volumes quickly,

· it should be capable of acting rapidly to cause unconsciousness when breathed in - perhaps acting over the span of 10 or 12 breaths,

· it should then be very safe so that even if an unconscious person continues to breathe the gas for several minutes or hours it should not cause any further damage or complications and lastly,

· the effect of the gas should be rapidly reversible. That is, after the exposure is complete, then either the body should spontaneously wash out the gas or an antidote should easily reverse its effect.

Unfortunately such an ideal `knock-out’ gas or compound does not exist.

The most commonly employed agents that rapidly cause unconsciousness are used routinely for general anesthesia for surgical operations. But every single one of these agents has drawbacks that make it less than ideal for use as a gas to render people unconscious, safely and securely, without intensive (close) medical supervision.

Some chemical agents may not be reliably absorbed from the lungs when breathed, and are best given as injections or tablets. Others may act very slowly, even if absorbed from the lungs. These are obviously unsuitable, and can be ruled out.

Many agents have a characteristic odor that makes them easily detectable. Some are irritant and may cause coughing or burning of the eyes. Either way, the use of such agents could trigger a dangerous panic reaction from a tense, tired hostage taker before they cause unconsciousness.

Some agents occur as powders or liquids, and these will need to be dispersed in the air for them to be inhaled. This may not be a very difficult technical hurdle to cross. Many countries, and Russia in particular have developed great expertise in creating aerosols from liquids or powders. Aerosols (7,8) are minute droplets or powders suspended in a gas. Aerosols can be generated from powders or liquids by accurate control of particle size, shape, concentration and electric charge (9) The Federal Institute of Applied Chemistry in Russia (10) has developed great expertise in this area.

If all the above conditions are adequately met, there still remains the crucial question of safety. Contrary to popular belief chemical agents that cause sedation, narcosis or loss of consciousness do not cause "sleep" in the true sense of the word. A person who is asleep is `rousable’, i.e. the person is able to regain full consciousness rapidly. A person who is under the influence of a drug that causes unconsciousness is in a state akin to a drunken stupor.

All the agents used suppress brain functions to cause this stupor, and whenever brain function is suppressed the part of the brain that controls breathing is also suppressed to an extent. A higher the dose of the "knockout agent" causes greater the suppression of breathing. In addition to this a higher dose can also trigger of other side effects lead eventually to a cascade of events in the body that can cause death. Unlike injections or tablets that provide a fixed dose of chemical agent to the body, an agent that is present in the atmosphere will be inhaled with each breath and the dose of the substance reaching the blood and brain will increase with each breath and eventually lead to possible fatal over dosage unless the chemical laden air that is being breathed can be quickly replaced and substituted with normal air or oxygen. A number of individual factors may delay or accelerate death under such circumstances. Younger people with healthy cardiac and respiratory systems will last longer as may people who are drug addicts or alcoholics, whose bodies may destroy some agents faster than normal. Elderly people with heart disease, and people weakened by disease or starvation and dehydration will likely succumb quickly.

This sets the stage for the effects of introducing an anesthetic or sedative gas into a confined space, such as was done in Russia. Within the space, people sitting near vents through which the gas is introduced will receive higher doses more quickly than those sitting away from vents, and in these areas, the elderly and weak will succumb soonest from an overdose, possible even before others in other areas lose consciousness. This theoretical model fits in well with the reports of the Moscow siege, with a mixed picture of people who were conscious and unconscious, some deaths, while some people remained relatively unaffected. In the next section we proceed to discuss specific agents and their likely impact.

A Discussion of Potential Agents

Potential Agents, which satisfy some, or most of the requirements we have seen above are Nitrous Oxide, Halothane, Enflurane, Isoflurane, Sevoflurane, and Desflurane. Other volatile agents which do cause loss of consciousness, but are unfit for a mission such as the Moscow theater crisis are Vallium, Chloroform, Cyclopropane, Methoxyflurane, Trichloroethylene, Fluroxene, and Diethylether. There are a number of agents currently under research and these might qualify as anesthetic agents in the future. Some of these are Xenon, Compound 485, Thiomethoxyflurane, n-Pentane, and Diosychlorane. In addition, Argon, Nitrogen, and Hydrogen also induce anesthetic effects, but they are rarely used in the medical community for various reasons. We omit other excellent anesthetic drugs like Ketamine for the inability to administer them in gaseous or aerosol forms. We will also consider Opiate derived drugs and reasons why it was chosen over others in the operation to neutralize the Chechen Terrorists inside the Moscow Theater. We will consider the most likely agents and their pros and cons and thus, the suitability of their usage in a hostage situation.

On a slightly technical note, readers must bear in mind that the potency of an anesthetic gas can be defined by the concentration required to prevent movement in response to a painful stimulus in 50% of patients/subjects. It is customary to use the Minimum Alveolar Concentration (MAC) value, as a measure of drug potency. Anesthetic agents with low MAC values are more potent.

1. Nitrous Oxide and Ether: As the only organic gas practical for clinical anesthesia, Nitrous Oxide is denser than air, colorless and tasteless, but has a slightly sweet odor. It supports combustion as actively as oxygen and thus it is flammable. As a result it does not fit in the profile of a safe and undetectable gas usable in a hostage situation. Nitrous oxide has low solubility in blood and requires up to 100% concentration to induce anesthesia or unconsciousness although it has a rapid onset and recovery with minimal cardiovascular and respiratory effects. It is comparable to Ether, which also has a characteristic smell which makes it unpleasant to breathe, highly volatile and explosive in the presence of Oxygen. Ether is also associated with a slow onset and a slow recovery in addition to causing irritation of the Lungs (bronchial tree), which may slow down the induction of anesthesia and thus causes nausea and vomiting much more than any other agent. (16)

2. Halothane (Fluothane): Halothane has a near-perfect profile of physical properties. It is well tolerated by human body; non-irritant and adequately potent (Low MAC) since it is relatively insoluble in blood, giving rapid induction, low dose management and rapid recovery. Therefore it is known as the ideal inhalation induction agent. However on the cons side, it is perhaps too potent and overdose is easy. It also requires that Oxygen be induced side by side to avoid hypoxia or oxygen starvation for the brain. Thus Halothane can be set aside for use in a strictly clinical setting.

3. Isoflurane: Isoflurane (and Enflurane) have a lower side effect profile and a more rapid offset of action when compared with halothane, but Isoflurane has a irritating pungent odor and thus undetected induction is not possible. Otherwise Isoflurane is one of the most widely used inhalation agent. (17)

4. Desflurane: It needs specially designed vaporizers and thus, is not suitable for mobility that is necessary for optimum tactical usage. (17)

5. Sevoflurane: It has a ultra low solubility and thus results in ultra rapid induction and at the same time, rapid recovery which is attractive for use in a hostile situation involving hostages. It is also non-irritant (like Halothane) but its sweet smell is easily detectable and therefore it is disqualified for usage in a scenario similar to the Moscow Theater Crisis. (17)

6. Valium (Diazepam): Dr. Christopher Holstege, medical toxicology director at the University of Virginia first speculated that the Russian authorities could have used aerosolized Valium. However the authors feel it too has to be rejected. As any other benzodiazapine Valium is an anti-anxiety and anticonvulsant (muscle relaxation) drug that causes only minimal sedation. Although it is possible that Valium might have been used in combination with some more potent anesthetic. Versed (Midazolam), another benodiazapam derivative, has shorter half-life (of about 2 hours). It has limited cardiovascular effects, allows for expeditious recovery, and has no post-op effects such as nausea and vomiting. However Versed is difficult to administer in gaseous or aerosol form. Furthermore it requires expert handling and cautious use in view of possible respiratory depression leading to inadequate oxygenation (15)

7. BZ gas: Experts have also mentioned BZ, or 3-quinuclidinyl benzilate, as a possible candidate for the gas used by the Russians. It belongs to a class of drugs known as anticholinergics that interrupt the brain's chemical messaging system between cells, leading to confusion and hallucinations. BZ takes an hour to start working and its effects peak at eight hours - whereas the Russian gas worked in seconds. Moreover, a hallucinogen seems a risky choice for terrorists strapped to bombs, as it makes them more unpredictable.

8. Opiate Derivatives: Opiods are a family of substances ranging from the well-known natural opium, morphine to relatively unknown Fentanyl, Sufentanyl, Meptazinol, etc. Most Opiods make good analgesics: They are well known for their ability to reduce the perception of pain without a loss of consciousness. For our consideration of potential tactical usage agents, we will concentrate on Opiate derivatives that also induce unconsciousness, such as Fentanyl. Fentanyl citrate is one such synthetic Opioid related to phenylpiperidines. It is an aqueous citrate salt of Fentanyl and can be converted into an aerosol for inhalation. Fentanyl is about 80 times as potent as morphine and brings about anesthesia in adults with spontaneous respiration. It acts on the “µ1” Opiod receptors and thus brings in supra spinal analgesic and sedation. Its low detectability and fast but brief action makes it an attractive agent for usage in a situation similar to the Moscow theater crisis. However, Fentanyl has some side effects, of which nausea, vomiting, drowsiness and confusion are some. Larger doses produce respiratory depression, hypotension with circulatory failure and deepening coma. These and the other pharmacological effects of Fentanyl, can be reversed by specific narcotic antagonists (eg. Naloxone). The usage of Naloxone by doctors in Moscow hospitals for treatment of released hostages gave away the first clue to the correct assessment of the gas by doctors attached to the American Embassy in Moscow. (14) The authors do not know how Fentanyl Citrate, a salt usually administered in IM/IV/transdermal form was converted into an aerosol. Given the limited information available on military drug development, it is impossible to be very specific about this and detailed analysis of this is beyond the scope of this paper. Soviet military drug development was of a very advanced nature as the prospect of CBW being used in a military confrontation was taken very seriously by the military planners. Russia has inherited most of the old Soviet infrastructure, and it is not implausible to expect that they have succeeded in producing an aerosol version of Fentanyl Citrate or some other Fentanyl derivative that can be dispersed through the air.

People most at risk from the effects of overdosing on Opiate derivatives like Fentanyl are those with pre-existing health conditions, such as chronic asthma or other serious respiratory problems, liver damage (such as in alcoholics or diabetics), various heart conditions. Stress, hunger and dehydration – all experienced by the hostages - would greatly compound any such risks.

Conclusions

Thus we have analyzed a range of volatile agents that can induce anesthesia or unconsciousness with reference to a set of requirements necessary for a particular agent to qualify as near-ideal candidate for use in a hostage rescue situation. The inadequacies in the current technologies in this field are now clearly visible.

The Moscow theater hostage drama and the subsequent Russian response has demonstrated the need for law enforcement bodies around the world involved in counter-terrorism activities to actively pursue programs for research and integration of chemical agents usage to traditional methods of hostage crisis resolutions.

References

1. http://in.news.yahoo.com/021025/137/1wxhr.html

2. http://www.bayarea.com/mld/bayarea/news/world/4370982.htm

3. http://story.news.yahoo.com/news?tmpl=story2&cid=564&ncid=564&e=3&u=/nm/20021027/ts_nm/russia_siege_dc_65

4. http://story.news.yahoo.com/news?tmpl=story2&cid=524&u=/ap/20021030/ap_wo_en_po/russia_theater_raid_299&printer=1

5. http://www.alertnet.org/thenews/newsdesk/L30350073

6. http://www.boston.com/news/daily/30/russia_gas.htm

7. http://terra.nasa.gov/FactSheets/Aerosols/

8. http://www.aerosol-soc.org.uk/aerosols.asp

9. http://www.biral.com/aerosol/aerosolgeneration.htm

10. http://www.milparade.com/1998/26/046.htm

11. Harrison's Principles of Internal Medicine, Isselbacher et al; McGraw-Hill, 1994.