Junichi Matsumoto, acting head of Tokyo Electric Power Co.'s Nuclear Power & Plant Siting Division, acknowledged the seriousness of the Fukushima accident at a press conference Tuesday. "Although the details of the [Chernobyl and Fukushima] accidents are different, from the standpoint of how much radiation has been released, [Fukushima] is equal to or more serious than Chernobyl."

"Though these substances don't pose a hazard to human health in the short term, if radioactive material keeps being discharged, the likelihood of it entering people's bodies through the food chain will increase," Kasai said.