NV/HEG Mtg.-Sept. 26-27, 1968 Page 3 picocuries of 1-131 per kilogram of forage and from this level to more accurately estimate the peak level of radioiodine in milk which will occur at that T-131, location at some later time. Milk is then measured for the peak of which should occur between two and four days after the test, providing a final confirmation of any potential problem. The substitution of uncontaminated hay for contaminated green forage can reduce the potential radioiodine in milk and ultimately the resultant dose to humans, depending upon the time intervening between the test and the substitution. For example, the substitution of uncontaminated hay on D+3 days can reduce the potential dose about 70 percent compared to total dose when no countermeasures are employed. Prediction before the test event has been primarily the function of ESSA. The source information is provided by the Laboratory conducting the test. Then, based upon certain meteorological assumptions the wind speeds, diffusion, dispersion, (shear, etc.) ESSA predicts a depo- sitionvalue in picocuries per square meter. Using the information collected from various tests and experiments the PHS has constructed various graphs and tables by which rough estimates a: om of the radioiodine level to be expected in milk can be made following a test. Various conditions of green forage densities, and hay ingestion have been covered. pasture types, Peak gamma exposure gate readings at the time of cloud passage are corrected to H+6 hours and have been correlated to peak I-131 milk concentrations. Soiatateietinn SNL