Their determination? "The first radiation measurements from within a 37-mile radius of the disabled Fukushima Dai-ichi power plant do not reveal any immediate health threat – and perhaps not even any health problems measurable decades from now, if levels stay where they are."
But it's all about the "if." The greatest concern right now is that the situation is not yet stable; if that doesn't change, the possibility of a catastrophic radiation leak exists. (Image: NPR)