As workers battle to cool spent fuel rods and damaged reactors, Japan's nuclear safety agency raised the assessment of danger to 5 on a scale of 7. That makes the crisis comparable to the partial meltdown at Pennsylvania's Three Mile Island reactor in 1979, but not to the total meltdown at Chernobyl in 1986. In the only country ever struck by atomic bombs, is there residual fear of radiation — even for medicine? What must it be like for the workers trying to control one of history's worst nuclear calamities? We speak with former inspector who blew the whistle on the situation at the Fukushima Daiichi nuclear plant, a Hiroshima survivor and others.