establishing the OEG. There are three degrees of risk: negligible, moderate, and emergency. Each of

these can be applied to radiation hazards resulting from enemy or friendly weapons, or both. It can also

be applied to initial nuclear radiation resulting from planned friendly supporting fires.

a. Degrees of risk are defined in terms of the expected response of personnel who are exposed to

nuclear radiation. These responses are expressed as a percentage of casualties or reduction in

performance. Vomiting is one effect that is considered to cause reduction in performance. The radiation

aspects of degrees of risk are discussed in Lesson 1.

b. It is important for you to understand and remember that the negligible risk dose of 50 cGy,

moderate risk dose of 70 cGy, and emergency risk dose of 150 cGy are for units with no previous

radiation exposure. After a unit has been exposed to nuclear radiation, the risk dose will be less, as shown

in Table 3-2.

c. The commander can establish the OEG using the degree-of-risk exposure chart. When doing

this, the commander must consider the RES of subordinate units and the degree of risk that will be

accepted.

(1) Use the degree-of-risk information. The possible exposure criteria for a single operation

and the dose criteria for a stated degree of risk are given in Table 3-2. The risk criteria for units in RES-1

and RES-2 are based on assumed average exposure (40 cGy for RES-1 and 110 cGy for RES-2). These

average criteria should be used only when the numerical value of the total past cumulative dose of a unit

is UNKNOWN. When the cumulative dose is KNOWN, the risk criteria are obtained by subtracting the

actual known dose from the RES-0 criterion. The following examples give calculations of the degree of

risk for both criteria:

(a) Calculate the degree of risk when the total cumulative dose is KNOWN. A unit is

known to have received a total cumulative dose of 30 cGy. How much more radiation can this unit

receive before exceeding a negligible risk?

Step 1. You know that the total cumulative dose of the unit is 30 cGy.

Step 2. You know that the commander does not want to exceed a negligible risk.