Review of the Department of Defense Research Program on Low-Level Exposures to Chemical Warfare Agents (2005) / Chapter Skim
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2 Understanding the Problem of Low-Level Exposure to Chemical Warfare Agents
2 Understanding the Problem of Low-Level Exposure to Chemical Warfare Agents
Pages 16-29
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From page 16... ...
; however, nerve agents are of immediate concern to DOD. Throughout the Research Plan, the effects of miosis are referred to as the operationally relevant performance decrements of primary importance.
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From page 17... ...
One of the issues for the committee was framed by DOD at one of its presentations in terms of the question, When can warfighters safely remove their protective masks without suffering significant performance decrements (miosis) caused by low-level exposure to nerve agents in the environment?
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From page 18... ...
The nerve agents are organophosphorus compounds and their toxicity is primarily related to inhibition of the enzyme acetylcholinesterase (AChE)
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From page 19... ...
. TOXICOLOGIC STUDIES For nerve agents, extensive toxicologic studies, including sensitive screening methods, have been conducted in various animal models.
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From page 20... ...
Studies have been performed with long-term exposure to symptomatic nonlethal doses of nerve agents (G agents and VX)
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From page 21... ...
The strongest evidence in humans of a possible long-term effect of exposure to nerve agents is from studies reporting changes in EEGs. No single study or set of studies exactly addresses the acute and long-term changes in EEG activity produced by nerve agents.
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From page 22... ...
However, the control group in this study also had changes in their sleep patterns that differed from the general population. The 77 workers exposed to agent GB reported no adverse health effects and no behavioral changes.
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From page 23... ...
received one or more of 254 chemicals in five classes, including nerve agents. In the early 1960s, 1,406 healthy soldier volunteers, mostly 20-25 years of age, were tested with single or multiple doses of one or more of 15 anticholinesterases, including the OP esters GB (n = 246)
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From page 24... ...
The committee's first report (NRC 1982) found no evi-dence to support a finding of adverse long-term or delayed health effects after exposure to nerve agents.
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From page 25... ...
Department of Health and Human Services in the Federal Register on March 15, 1988, it was stated that "Questions related to the nerve agents proved relatively easy to resolve. The information bases are fairly complete, and there appears to be little risk either of adverse health effects from long-term exposure to low doses or of delayed health effects from acute exposures." Furthermore, the NRC was confident that its analyses of the Army human volunteer subjects program would have had the power to detect major adverse health consequences had they been present; however, minor or subtle effects could have gone undetected.
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From page 26... ...
The commander must have evidence that there is a hazard and that the hazard poses a threat. In other words, the commander or decision maker must have the ability to know if a CWA is present and at what concentration and if that concentration can induce adverse operational impairments or adverse delayed health effects in exposed personnel.
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From page 27... ...
If possible, it might be informative to plot the probability of miosis given CWA exposure versus the probability of severe dehydration or other operational end points for a number of concentration-time combinations. Because these effects differ in severity, an even more important comparison is the probability of an operationally relevant decrement in performance due to CWA exposure versus
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From page 28... ...
. One of the main objectives of the Research Plan is to support operational risk management decisions with focused research.
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From page 29... ...
In summary, DOD requires accurate and reliable estimates of the effects of low-level CWA exposures on human performance. DOD states that accurate estimations cannot be derived from the universe of existing data on studies with animals and human research subjects and proposes in this Research Plan a multiyear, multimillion dollar research effort to acquire such information.
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