Appendix

Offensive Versus Defensive Use of Human-Toxicity Estimates for CW Agents

Perhaps the single most important factor to consider about many of the existing human estimates is that they appear to have been developed primarily for offensive purposes. This is summarized in the following paragraphs excerpted from Silver's (1953) report on GB (CDEPAT 1994):

While it is possible to calculate, on a fairly logical basis, an LCt50 for resting man, it is not possible to give a single figure for the LCt50 which would apply to all other states of activity. The actions of soldiers in combat are so varied and unpredictable that the respiratory minute volume at the moment of chemical attack would be quite impossible to determine.

At the risk of over-simplification, this problem can be solved for all practical purposes. Offensive tactics, to be successful, must be designed to produce the highest Cts necessary to cause casualties in all possible combat situations. In the case of toxic gas warfare, the highest LCt50 is required for resting men since their minute volume is the least. For all offensive calculations, therefore, the LCt50 for resting man should be used. Any extra casualties caused by increased respiration due to activity should merely be considered as bonus effects.

On the other hand, for defensive uses, protective equipment should function under the most adverse conditions. For example,



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 80
--> Appendix Offensive Versus Defensive Use of Human-Toxicity Estimates for CW Agents Perhaps the single most important factor to consider about many of the existing human estimates is that they appear to have been developed primarily for offensive purposes. This is summarized in the following paragraphs excerpted from Silver's (1953) report on GB (CDEPAT 1994): While it is possible to calculate, on a fairly logical basis, an LCt50 for resting man, it is not possible to give a single figure for the LCt50 which would apply to all other states of activity. The actions of soldiers in combat are so varied and unpredictable that the respiratory minute volume at the moment of chemical attack would be quite impossible to determine. At the risk of over-simplification, this problem can be solved for all practical purposes. Offensive tactics, to be successful, must be designed to produce the highest Cts necessary to cause casualties in all possible combat situations. In the case of toxic gas warfare, the highest LCt50 is required for resting men since their minute volume is the least. For all offensive calculations, therefore, the LCt50 for resting man should be used. Any extra casualties caused by increased respiration due to activity should merely be considered as bonus effects. On the other hand, for defensive uses, protective equipment should function under the most adverse conditions. For example,

OCR for page 80
--> leakages of gas masks should be so small that even men performing heavy work and breathing at high rates should suffer no ill effects. This same reasoning applies to all other protective devices. For all defensive calculations, therefore, the incapacitating exposure (ICt50) for active man should be used. Although much consideration has been given to the soldier's activity level and resultant respiratory minute volume in developing human toxicity estimates, little consideration has been given to the purpose of many of the existing human-toxicity estimates for CW agents: Many were probably formulated for offensive purposes. Offensive estimates are designed to produce the desired effect in at least the stated percentage of the population and to produce that effect quickly. The time required for CW agents to produce an effect is generally inversely proportional to the dose received. For defensive purposes, those factors (for example, high minute volume or the use of most resistant individuals in developing human toxicity estimates) result in an underestimation of the potency (toxicity) of the agents. Reference Silver, S.D. 1953. The Estimation of the Toxicity of GB to Man (U), MLRR 23, Chemical Corps Medical Laboratories Research Report, Army Chemical Center, Md., June 1953. Confidential report.