Strategies to Protect the Health of Deployed U.S. Forces Detecting, Characterizing, and Documenting Exposures (2000) / Chapter Skim
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3 Thresholds of Health Effects for Chemical and Biological Agents
3 Thresholds of Health Effects for Chemical and Biological Agents
Pages 50-67
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From page 50... ...
In contrast to high-level exposures for which the severity of effect tends to increase as the level of exposure increases, it is postulated that as low-level chemical exposures increase, the probability of disease increases. These concepts are commonly used to assess risks from exposure to chemical agents but have not been tested for biological agents.
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From page 51... ...
In addition to exposure to chemical agents, troops may be exposed to a number of other potentially harmful agents during military deployments. Among these nonwarfare agents are volatile components and combustion products from propellants, explosives, and pyrotechnics (PEP)
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From page 52... ...
concept used by the EPA as the maximum concentration of a contaminant to which a person could be exposed for 30 minutes without experiencing any escape-impairing or irreversible health effects. ICt50 is the incapacitating effect of a vapor or aerosol agent, which is the product of the concentration and exposure time sufficient to disable 50 percent of a group of exposed, unprotected personnel at an assumed breathing rate (active or resting)
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From page 53... ...
Toxic Industrial Chemicals In addition to traditional chemical warfare agents, deployed troops can be exposed to many other harmful chemicals, from environmental and occupational chemicals to TICs. These harmful chemicals may be a source of low-level exposures; they may even produce a chemical cloud that can degrade mission performance as much as some warfare agents.
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From page 54... ...
Railroad tank cars and tanker trucks also carry a variety of highly toxic chemical agents and reactive intermediate agents for chemical synthesis. These cars and trucks are moving targets of opportunity.
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From page 55... ...
Damaged or nonoperational infrastructures can also be a source of harmful exposures. Another source of toxic chemicals is the transformation of common industrial chemicals into more toxic species by environmental processes.
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From page 56... ...
Biological warfare agents can be disseminated as aerosols, liquids, or powders or can be introduced directly into food or water. Current biological agents of concern to DoD include viruses, such as eastern equine encephalitis, western equine encephalitis, Venezuelan equine encephalitis, ebola, marburg, rick-borne encephalitis, smallpox, Congo Crimean hemorrhagic fever, junin, lassa, machupo, monkeypod, Rift Valley fever, and yellow fever; bacteria, such as Bacillus anthracis, Brucella abortus, Brucella melitensis, Brucella suds, Burkholderia mallet, Burkholderia pseudomallei, Francisella tularensis, Yersinia Testis; and rickettsii, such as Coxiella burnetti, Rickettsia prowozeki, and Rickettsia ricketsii.
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From page 57... ...
So far, little attempt has been made to set performance goals for detecting biological toxins even though some toxins, such as Botulinium, are many times more toxic than chemical agents, even lethal chemicals. Because of their lethality at relatively low doses, biological toxins could pose a threat comparable to the threat of many chemical agents.
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From page 58... ...
for still others, the cumulative intake or uptake during a series of exposures is the critical parameter. Dose-response information for chemical agents at low doses and low dose rates is still insufficient for determining safe doses (NRC, 1997c; GAO, 1998~.
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From page 59... ...
Figure 3-2 illustrates the range of sensitivity required for detection/monitoring equipment to protect against a range of health effects. This figure shows how the EC50, the 30-minute average air concentration that would result in the LCt50, compares to the estimated safe dose and to the Surgeon General's AEL.
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From page 62... ...
GA GB BD VX CG DP AC CK SA H HO HN-1 L HE PD Agent code FIGURE 3-1 Variations in the median lethal air exposure, LCt50, and median incapacitating air exposure, ICt50, for some chemical warfare agents.
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From page 63... ...
~ ~ ~ C C O O _ ~ ~ ~ > > E ~ S 2 ` S S S , O ~ ~ S ~ SO i _ s ,0 a) s ~ ~ > I m 11 Chemical Agents FIGURE 3-3 Estimated safe air concentrations for some TICs regulated by the EPA and some chemical agents.
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From page 64... ...
. development of a strategic plan Its under wayl for research into the potential health consequences of exposure to chemical or other hazards, including low levels of chemical agents.
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From page 65... ...
has published Technical Guide 230A, Short Term Chemical Exposure Guidelinesfor Deployed Military Personnel, which can be used to address the potential health risks that may be experienced by deployed military personnel following temporary or short-term exposure to a number of toxic chemicals. The report gives Military Air Guidelines-Short Term and Military Water Guidelines-Short Term for chemical warfare agents, military smokes and obscurants, riot control agents, and TICs.
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From page 66... ...
Exposures could have long-term health effects that cannot be easily distinguished from the long-term health effects of low-level exposures to chemical warfare agents. Detecting and monitoring exposures continually to the full set of toxic chemicals would be extremely difficult, if not impossible.
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From page 67... ...
If possible, these medical problems should then be evaluated in terms of any prior exposures to chemical and/or biological warfare agents that have been associated with that health outcome. This plan should include guidelines for who should get the information and when they should receive it.
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