returned more slowly and even at two and three years post-exposure the mean levels were slightly below the unexposed mean levels (Fig. 3). By four years they had reached the unexposed levels and remained so at the time of the five year survey. Platelet levels showed the slowest recovery (Fig. 4). A rapid recovery trend followed the early depression, after which there was slower increase with mean levels remaining consistently below the unexposed mean population level. At the five year survey the males were about 13 per cent and the females 11 per cent below the corresponding mean levels of the comparison population, though the individual platelet counts were within the normal range. The mean red blood count, hemoglobin and hematocrit levels, were about the same in the exposed as in the unexposed group. 08 ee “ 7 o_ ~e — —* 4 MALES (AGE >10) i ~~" 1 zh Od oO PLATELETS x 10°* ro 3} oO pO se oO t + Ps ay x 40 1 L 2 L 1 40 DAYS L Ss6 L 7 TIME af i, AL 6 MO | 1 2 AFTER EXPOSURE L 4. 3 4 YEARS i 5 Fig. 4: Mean platelet counts of exposed Rongelap people from time of exposure through five years post-exposure. Stars represent mean values for comparison populations The 18 Rongelap people who had received about 70 r at Ailingnae Island showed less severe early hemopoietic depression but have also shown a similar slow recovery rate of lymphocytes and platelets as noted in the more heavily exposed group. The incidence of diseases, infectious or non-infectious, has remained about the same in the exposed as in the unexposed population. Three deaths have occurred: one in a +6 year old man during the second year after exposure from hypertensive heart disease which had been present at the time of exposure; the second in a 78 year old man at three years after exposure of coronary heart disease complicating diabetes; and the third in a 36 year old man at four years after exposure of acute varicella. 318