The scientists knew and understood the risks of radiation. A few had already died from accidents during the making of the bomb. The government considered it a

The scientists knew and understood the risks of radiation. A few had already died from accidents during the making of the bomb. The government considered it a calculated risk - as they did with the soldiers sent to the bombed cities after the war. In war you have to send people into harms way, its not much different from making men land on a beach with machine guns trained on them. One thing is pretty clear though, they didn't want to publicize the radiation effects on humans. Those they sent to Hiroshima were there to study the victims not to help and many didn't know the health effects they would soon personally suffer.