Get ready for a rash of stupid posts like the one linked below. The author comes up with a half-ass answer that exposure to twice the normal level of radiation equals only a 1 percent increase in cancer. These are the kinds of arguments that are used to justify ignoring a threat. I believe counselors would call this rationalization or denial.
Each one of us is an individual with different pre-existing conditions, differing levels of exposure to radiation, age and diet. All of these factors will change the effects of radiation exposure. People at the plant maybe exposed to only 20 rem but they may be getting much more from the atmosphere, water they drink and food they eat. We don't know how much radiation may already be present in their bodies. They may already have cancer cells present and even a 1 percent increase translates into a much higher incidence for the individual.
We haven't even discussed birth defects. How will the exposure to increase radiation effect pregnant moms or couples looking to have babies in the near future?
The situation in Japan is serious and worse we are going into unchartered waters. People in California are running out buying iodide tablets but how much radiation have they been exposed to already (from food and other environmental factors unrelated to the Japanese reactors?). Stupid shit that is going to create unsubstantiated confidence that they didn't exposed to too much radiation.
Radiation: Dose and Risk - Boing Boing