BOX 4-1 Criteria for CCEGs and MEGs


  • Include chemicals likely to be encountered in sufficient quantities to degrade mission effectiveness.

  • Include health effects that are manifested within minutes, hours, or several days that could immediately affect the functioning of troops (e.g., loss of cognitive ability, loss of visual acuity, significantly reduced cardiopulmonary functioning, muscular weakness) performing a mission. Does not include long-term health effects (e.g., cancer).

  • Consider exposure time frames of hours, days, and weeks, rather than months or years.

  • Relate to the military population, which includes generally healthy adult men and women with typical variations in genetic susceptibilities.

  • Provide exposure-response and population-response information, insofar as possible. Include concentrations likely to cause effects in humans, along with a description of the severity and incidence expected. This information would enable chemical threats to be weighed in comparison to other mission threats (e.g., Table 3-1 in TG-230 would be more useful).

  • Provide guidance primarily for the air exposure pathway, because troops have no choice but to breathe the air (except when gas masks are used). Theoretically, the water pathway might influence CCEGs, but the availability of alternative sources of water makes it relatively less important. Water exposure scenarios of special concern should be identified and addressed. Soil also deserves some consideration, but is unlikely to be a significant source of exposure.


  • Include a large number of chemicals likely to be present in deployments.

  • Include concerns over longer-term health of individuals recognize that exposures at these levels would have no to minimal impact on immediate missions.

  • Include virtually all exposure durations from 1 hour to 1 year.

  • Relate to the military population.

  • Indicate protective levels (i.e., levels assumed to represent no adverse effects or very low risk) for the exposure durations of interest.

  • Provide guidance for management actions when MEGs are exceeded.

ble soldiers from engaging in heavy exercise. At a higher concentration, the average soldier might be affected, further reducing unit strength. Long-term exposure at lower concentrations of the same chemical might not cause near-term effects on pulmonary function, but could cause alterations in lung structure much later. Some chemicals might produce a continuum of effects; others might elicit different acute and chronic effects. For example, the likelihood that short-term exposures to relatively low concentrations of chemicals would cause cancer many years later is remote. But, consider chemicals that adversely affect fertility. Knowledge that those chemicals

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