Ex Fukushima Chief Has Cancer

Masao Yoshida, the former head of the Fukushima No. 1 plant, has esophageal cancer, Tokyo Electric Power Co. said Friday.

The cumulative amount of radiation Yoshida, 56, was exposed to since the nuclear crisis started in March was 70 millisieverts, Tepco said, adding it is unlikely his cancer is linked to the radioactive materials spewed by the plant's crippled reactors. Tepco, however, said no signs of esophageal cancer were detected during Yoshida's regular checkup in autumn 2010.

Tepco noted that Makoto Akashi, executive director of the National Institute of Radiological Science, estimates that the incubation period of esophageal cancer is around five to 10 years.

Yoshida, however, visited the Fukushima No. 1 plant Friday and talked about his illness with workers at the facility, fearing media speculation about his health may be affecting the morale of plant workers and their families.

Yoshihisa Matsumoto, an associate professor at Tokyo Institute of Technology's Research Laboratory for Nuclear Reactors, told The Japan Times he also believes the link between Yoshida's cancer and the nuclear disaster is highly improbable, given the amount of radiation he was exposed to and the short incubation period since the crisis started. Matsumoto said no deterministic effects from 70 millisieverts or less have been found.

Tepco said Yoshida does not wish to disclose further details about his illness, such as how bad the cancer is, where he is hospitalized and what treatment he is currently receiving. Yoshida worked in the Fukushima plant since June 2010. He left his post Nov. 14 on health grounds.