U.S. agencies continue to say "no harm to human health" even as Japanese radioactive releases from the Fukushima reactors literally rain down on some U.S. states. However, it is important to bear in mind that (a) there is no safe dose of radiation - this is supported by the National Academy of Sciences (b) Any additional and unnecessary exposures to radiation are potentially harmful and (c) the so-called "safe dose" calculation is based on the amount of radiation a healthy, white male in his 20s and 30s could tolerate. The same dose inflicted on a child, a pregnant woman or a fetus is far more harmful.