The water three men were exposed to while working at the Fukushima Daiichi nuclear power plant had 10,000 times the amount of radiation typical for that locale, an official with the Japan nuclear and industrial safety agency said Friday.
The contamination is likely from the No. 3 reactor's core, the official, Hidehiko Nishiyama said.
He said there's a possibility of "some sort of leakage" -- including potentially from a crack in the unit's containment vessel, CNN International reports.
Japan's effort to contain the crisis at the Fukushima Daiichi nuclear plant suffered a setback, an official said on Friday, citing evidence that the reactor vessel of the No. 3 unit may have been damaged.
The development, described at a news conference by Hidehiko Nishiyama, deputy director-general of the Japan Nuclear and Industrial Safety Agency, raises the possibility that radiation from the mox fuel in the reactor - a combination of uranium and plutonium - could be released, New York Times reports.