“…Continued rainout of long-lived fission products, particularly strontium-90, accumulated in the stratosphere may, however, constitute long-term problems as suggested by Kramer and colleagues (1). Total beta rainout has remained high during the period from January to June 1959, amounting to 284 mJLc/sq m at La Verne, only slightly less than the total rainout of 327 muc/sq m from February to June 1958.…”