in april 2011, the united states department of energy published projections of the radiation risks over the next year for people living in the neighborhood of the plant. potential exposure could exceed 20 msv/year (2 rems/year) in some areas up to 50 kilometers from the plant. that is the level at which relocation would be considered in the usa, and it is a level that could cause roughly one extra cancer case in 500 young adults. natural radiation levels are higher in some part of the world than the projected level mentioned above, and about 4 people out of 10 can be expected to develop cancer without exposure to radiation. further, the radiation exposure resulting from the accident for most people living in fukushima is so small compared to background radiation that it may be impossible to find statistically significant evidence of increases in cancer.