People wearing surgical masks leave Shimbashi train station in Tokyo Wednesday, March 16, 2011. The nuclear crisis has triggered international alarm and partly overshadowed the human tragedy caused by Friday's earthquake and the subsequent tsunami. (AP Photo/Eugene Hoshiko)

Photo by: Eugene Hoshiko

People wearing surgical masks leave Shimbashi train station in Tokyo Wednesday, March 16, 2011. The nuclear crisis has triggered international alarm and partly overshadowed the human tragedy caused by Friday's earthquake and the subsequent tsunami. (AP Photo/Eugene Hoshiko)