DEBORAH BROWN, et al., Civil Action No.H-95-587











1. My name is Eric R. Larsen. I am at present a consultant specializing in work relating to combustion properties of organic materials, fire technology, fire cause, origin and spread, and combustion modification (fire retardance) of polymers.

2. My experience is set forth in my curriculum vitae, which is attached to this declaration. I received my Bachelor of Science in chemistry from the University of Washington and my doctorate from the University of Colorado. I retired as a Senior Scientist at Dow Chemical Co. in 1986, after thirty years with the company. I hold 47 U.S. patents on chemical processes, including one on a halogenated anesthetic now used in about 90% of veterinary anesthesias. I have authored or co authored 35 scientific publications, including articles in the Encyclopedia of Chemical Technology on fire retardant chemicals and in Drugs Affecting the Nervous System on the mechanism of chemical narcosis. I am a member of the Editorial Advisory Board of the Journal of Fire Science.

3. I have also done extensive work in the field of anesthesia development and use. Thirteen of my patents, four of my papers, and three of my treatise chapters ("The Chemistry of Experimental Pharmacology," in Handbook of Experimental Pharmacology (1972); "Fluorine Compounds in Anesthesiology," in Fluorine Chemistry Reviews (1969) and [coauthored] "Mechanisms of Narcosis," in Drugs Affecting the Nervous System) relate to anesthesia and narcosis.

4. I have been asked to render an opinion on the probable effects of the CS gas injections into the Davidian residence at Mt. Carmel, outside Waco, Texas. In preparing this opinion I have consulted the study of the gassing undertaken by Failure Analysis Associates, sketches of the dimensions and internal structure of the building,the Forward Looking Infrared tape made of the fire, and MSDS (Manufacturers' Standard Data Sheets) for the chemicals involved. The two chemicals involved were o chlorobenzylidene malononitrile (commonly known as "CS"), and methylene chloride (MeCl2), in which the CS was dissolved before spraying. MeCl2 makes up the greater part of the solution: Ferret rounds, for instance, contain 33.25 grams of MeCl2 bearing 3.7 grams of CS.

5. In addition to the Ferrets, gas was injected using a system described in the Justice Department report as the "Mark V." This may be a description of either of two systems. The Model 5 injector carries in each "bottle" 30 grams (a bit over an ounce) of CS dissolved in 1070 grams (roughly 2.4 pounds) of MeCl2. The M5 injector carries no less than fifty pounds of CS in each container. In rendering this opinion I have assumed that only the smaller Model 5 was used. If in fact the M5 is the injector described, CS concentrations would have to be revised upward; we would then be speaking of tens of pounds per container, rather than an ounce. In that event, each injection would have sent a fuel load into the building equalling in effect the distribution of about 3-4 gallons of gasoline. Given that flame sources--lanterns, candles, etc.- were known to be inside, this would be consistent with a deliberate intention of starting a fire.

6. CS is a high-melting flammable solid (dust) whose sole use is as a "tear gas." Its effects are not limited to eye irritation and tearing, however. At 1-5 parts per million it produces eye irritation and a copious flow of tears. At concentrations of 12-20 ppm it attacks the respiratory tract and causes difficulty in breathing. In the respiratory tract or on moist skin it causes a chemical burn similar to sunburn and can be classed as a vesicant, similar to "mustard gas."

7. The CS was introduced dissolved in methylene chloride. MeCl2 is a small, highly volatile chlorinated hydrocarbon commonly used as a solvent. This compound is flammable in a vapor concentration greater than 12-14%; it is generally considered nonflammable so long as it is used in well-ventilated areas or in the open air. Like all small oil soluble compounds inhalation of its vapors causes "narcosis" or what is commonly called "anesthesia." The anesthetic properties in man are predictable to a reasonably high degree of accuracy based on animal studies. The anesthetic effects are a function primarily of concentration and are somewhat time-dependent at low concentrations.

8. The effects of the CS applied by the injector units can be briefly stated. Upon being sprayed, MeCl2 would rapidly evaporate, until only crystals (dust) of CS remained in the air. Depending upon the size of the original droplet the CS particles could be 1 micron or larger. Spray that wetted a wall would lead a deposit of CS that might or might not be a dust, but would slowly release and make the building uninhabitable for days or weeks: it would not be blown out by the wind. The initial spray would contain vapor concentrations of MeCl2 above its flammable limits. As it dispersed, the vapor concentration would become flammable, and as dispersion continued it would eventually fall below the flammable limits. As the MeCl2 droplets evaporated, the droplets would decrease in size and their flammability increase.

9. The same would be true, albeit on a smaller physical scale, for the impact of each Ferret round. That is, impact would produce what may be visualized as an expanding bubble of droplets and vapor. Within that expanding bubble there would be, for a certain tima core where the MeCl2 concentration is too high to ignite, an outer edge where it was too low to ignite, and an intermediate zone where the concentration was right for ignition. If the ignitable portion contacted a flame source such as a candle or a lantern, fire would result.

10. The narcotic effects of MeCl2 would follow a similar patterns. Anyone caught in the spray itself would experience tachycardia and possibly cardiac arrest. MeCl2 is known to sensitize the heart, particularly if the person is already under stress or fearful. In the case of most inhalation general anesthetics this effect is most pronounced if the person experiences a rapid change in the air concentration--partial pressure of the compound--of the agent. As the cloud expanded within the building anyone exposed would experience difficulty in breathing due to the CS. The MeCl2, being a potent anesthetic agent, would tend to alleviate the pain as narcosis set in and the brain began to shut down.

11. In lay terms, MeCl2 is a very potent, fast-acting inhalation general anesthesia agent--nearly on a par with Halothane, the most potent agent currently used in surgical anesthesia. When MeCl2 is inhaled, it moves from the lungs through the blood to the brain, where it interferes with the electrical activity of the cognitive function of the brain. Of the material inhaled, about one-third is transferred to the brain, where it partitions into the lipid portion of the nerve cells and essentially shuts them down. The remainder partitions into other lipid repositories of the body. As the lipid reservoirs are filled, it will be necessary to reduce partial pressure (concentration) of the gas or the degree of anesthesia will continue to increase until death results.

12. Anesthetic effects of MeCl2 on humans can be predicted from animal studies of Halothane. Studies of effects on dogs have been used for years to predict effects on humans, since anesthesia effects on the two species are similar. In the dog it has been shown that a concentration of 0.46% (volume) in inhaled air will eliminate spontaneous movement, 0.69% will produce nonreaction to an incision, and 0.81 will produce nonreaction to a tail clamp. Effects will vary from animal to animal. In any event, concentrations of MeCl2 only half those which Failure Analysis calculated were created by the injections into the Davidian residence would have rendered unprotected individuals unable to escape a fire.

13. I have attempted to determine the situation in the "vault" or "bunker," a concrete room where the deceased children and many of the deceased women were found. The injection of a single Model 5 bottle into this room would cause the occupants to become comatose and unable to escape. Two bottles could have raised concentrations to lethal levels. Four bottles (the load carried by some of the injecting vehicles) would have produced full anesthesia within 10-20 seconds and death unless there was some way to quickly remove the unconscious victims from exposure. If the MeCl2 dissipated between injections, the occupants would tend to recover between the injections: they would be cognizant of what was going on around them, but only in the sense that a "falling-down" drunk is cognizant. It is doubtful that they would be able to plan an escape. Those surviving each injection would have gone through cycles of pain from the CS, anesthesia from the MeCl2, and awakening to renewed pain from the CS. The exposure of a room of children to these cycles can aptly be described as torture.

14. Both the CS and the MeCl2 vapor would be flammable under the conditions of the injection. The CS dust would pose the risk of a flash fire; a dust explosion would be possible but I do not think likely. I do note that the lower explosive limit of CS dust is 25 parts per million, and the government's own experts, testifying during hearings in the House, indicated that concentrations up to 110 ppm were achieved by the injections. A thin layer of CS dust, or concentrated MeCl2 vapor, laying near the floor would suffice if the lower flammability limit is exceeded: this is what happens when flame follows a trail of gasoline vapor. As the flame moves it will create a draft and as air and additional fuel are sucked into the flame the fire ball may grow. I would expect such a fire to follow the hallways in the same way that fire will follow as gasoline vapor trail. Considering the direction of the wind and the fact that the fire behavior suggests most of the internal doors were closed, I would expect such a flash fire to move from the north end of the building down the hallways toward the kitchen and chapel. I note that some of the survivors have stated they witnessed a fireball flashing down the hallways. This is consistent with my analysis.

15. I have personal experience with flash fires--having been twice caught in them--and would not expect the flash fire itself to cause serious burns to persons whom it passed by. However, if the flash fire met materials which would act like tinder--hay, paper, spilled fuel--it would likely set these afire. If there were multiple sources of this tinder, such a flash fire would act as a quick fuse to start fires at various places in relatively short order.

16. During combustion, both chemicals involved produce toxic smoke. CS generates hydrogen cyanide, while MeCl2 generates hydrogen chloride and chlorine. Both give copious amounts of carbon monoxide.

17. To determine the exact effects of CS and MeCl2 on individuals and on the fire will require obtaining detailed information presently kept by the government. Dr. Uhlig, and Failure Analysis, estimate injection of about 7 gallons of MeCl2 and 2 pounds of CS. Figures given by the government's experts at the House hearings would extrapolate out to about twice these figures. Dr. Uhlig mentions other estimates which would put the figures much higher, up to 90 gallons. In my opinion, even if the lowest figures are used, many of the deaths of occupants, particularly of the children, were caused directly or indirectly by the effects of MeCl2 injected.

18. During the House hearings, a government witness testified that the Attorney General had been briefed on the case of a toddler who was exposed to CS and recovered without permanent harm. The case appears to be that reported in Park & Giammona, "Toxic Effects of Tear Gas on an Infant Following Prolonged Exposure," American Journ. of Diseases of the Child, vol. 123 p. 245 (March, 1972). The article, interpreted as showing recovery without harm, in fact suggests that two hours' exposure to CS placed the child in torment and in risk of death. The child was immediately treated, but required suctioning to relieve airway obstruction, experienced chemical burns to the skin, ultimately went into severe respiratory distress and had to be placed on a respirator. Those who advised on the gassing thus had actual knowledge of severe risks to children.

19. The manufacturers of these materials warn of risks of toxicity and fire in their MSDSs. Considering the number of "red flags" raised by even a casual reading of the manufacturer's literature, and the effort which went into planning, I find it improbable that those using CS and MeCl2 in the quantities used at Mt. Carmel did not have actual knowledge that their plan would result in deaths of persons inside.

I declare under penalty of perjury that the above is true and correct.


Eric Larsen, Ph.d.


Dated this 28th day of May, 1996.