Embassy of the United States in Tokyo, March 17th

mmm...

[...] Despite the best efforts of responders, the situation remains very serious. Given the situation, we recommended the evacuation of American citizens to at least 50 miles, in keeping with the guidelines applied in the United States. Since the continued or increased release of windborne radioactive material cannot be ruled out, American citizens in Japan are advised to take prudent precautions against potentially dangerous exposure. As a general matter, residents in areas further from Fukushima Prefecture face less risk of significant exposure, but changing weather conditions and wind direction means that radiation levels in the future might become elevated [...].