In reports of exercises researched to date, very few references to the possibility of internal exposures have turned up, and in these cases follow-up generally showed no contamination. On the other hand, many references have been found which indicate that at the time it was not necessary to exercise available contingency plans for particulate radioactivity. Several studies, some of which were conducted during the testing and others which were conducted subsequent to the testing, have shown that in many types of circumstances, if any significant amount of alpha particles had been inhaled the film badge readings for gamma radiation would have been quite high. The very nature of the alpha-emitting isotopes’ iong radiological half-life and long biological half-life, which leads to a long- term dose commitment when taken internally, also permits detection long after inhalation or ingestion. If alpha particles had been inhaled by participants during the 1950's at levels which are thought to result in biological effects, clear evidence could be found in their bodies today through bioassay and whole-body measurements of radioactivity.