levels in milk samples. Theoretical calculations of thyroid doses have been attempted, based on other types of radiation monitoring such as collection of radioactive particulates in the air or measurements of radiations at three feet above the ground from deposited fallout. date, all of these methods suffer severe uncertainties. To These monitor- ing procedures, equipment and data are useful the the purposes for which they were intended. The difficulty is in attempting to use one type to predict another in a quantitative way. EvaluationAll of the above calculated thyroid radiation doses may be placed in perspective by quoting from a National Academy of Sciences report: /1a" , . . There is no evidence at hand, except for one doubtful case in a child, that any of the treatments for hyperthyroidism has produced a thyroid cancer, although doses have ranged from a few thousand rad upward " There can be circumstances where levels of iodine-131 in milk can be a more controlling factor than external gamma exposures - that have hitherto been considered of prime interest for local fallout. Up-to- date techniques and equipment now permit a relatively easy and early surveillance of iodine-131 in the milk supply.