wittiie 2. a sasiabaiide CO cobolt~60, largely from activity induced in iroh used for towers, etc., in the tests. (Its 5-year lifetime makes waiting times for decay more acceptable). Na Sain si ie 3. various isotopes of plutonium produced from the capture of neutrons by uranium in the nuclear detonation. 4. The unconsumed plutonium and/or uranium used for the nuclear explosive but not having undergone fission. (When nuclear explo- sives misfire, the chemical-type high explosive used for assembling these nuclear components ultimately endsinstead in spreading them.) 5. * Tritium induced in water by neutrons and from thermonuclear reactions. (However, the mobility of the water in the ocean quickly dissipates thic hazard.) Even misfires or near misfires (low yield) of nuclear explosives result in a spread of radioactivity, as is seen by Item 4. In these misfire cases, the residual uranium or plutonium is deposited over a much smaller area than for the case of the spread from a nuclear explosive (perhaps square yards of spread in the former case, but worldwide or at least square miles in latter). misfires are essentially intentional in that they are safety tests. Some A par~ ticular concern in a misfire is the spread of plutonium-239; the lower radiological hazard of uranium-235 causes very much less of a radiological concern when used as the nuclear material. This plutonium concern is complicated by its long 24-thousand year half life for decay, which is far too long for planning on decay to eliminate the hazard. . Just such difficulties of plutonium contamination have occurred around Runit Island. For example, the test Scaevola in Operation Hardtack I was_a ene? rae