Our reaction to the crisis in Fukushima Daiichi has been and continues to be generally irrational. Contrary to the assertions of some recent sensationalistic articles, there is no evident increase in thyroid health problems in Japanese children living in and around the Prefectures of Fukushima, and it is unlikely that there ever will be (UN Report; Nuclear News; J. of Am. Phys. and Surg.; CBCnews; Hiroshima Syndrome; National Geographic; Asahi Shimbun). This is because the only cause of thyroid risk during a nuclear disaster, iodine-131 which has a half-life of 8 days, was allowed to decay during evacuation and with restrictions on food and milk from the area. After 80–90 days had passed, released radioactive iodine-131 decays to less than 0.1% of its initial quantity, and therefore the danger is essentially over. (These precautions were not well followed near Chernobyl and thus resulted in many health problems in future years for the people of Ukraine.)
In fact, it has repeatedly been shown that the worst health effects from Fukushima have come not from any radioactive exposure, but from the the stress of evacuations and fear of radiation itself (Gaji 2013; Japan Daily Press; WHO Report; NYTimes). “The psychological stress…we should never underestimate that…it’s really what the big problem is, because there’s a lot of fear which might actually cause health effects,” says Kai Vetter of UC Berkley nuclear engineering department. In fact, not one person has yet died from exposure to Fukushima’s radiation, and it’s likely that no one ever will.
In a closely related issue, our current EPA guidelines have an absurdly low threshold for radiation exposure. The EPA currently holds that an acceptable level of radiation is between 4 and 25 millirems per year: anything above that is considered a threat to the public. However unless you are living in a boat out in the middle of the Pacific Ocean, you’re getting a radiation dose between 200 and 1,000 mrem/year in the United States from background sources such as rock, dirt, potatoes and cosmic rays. These guidelines stem from an era where any level of radiation was considered dangerous to human health. Our understanding of natural and unavoidable background radiation has since been refined. Fortunately the EPA is planning to revise its guidelines to 5,000 mrem/year as a basis for evacuation, which is still quite a conservative threshold for the danger to human health from radiation.