Tokyo Electric Power Co. officials say the dangerously high levels of radiation detected Sunday were a mistake. The reading showed radiation levels 10 million times above normal in the No. 2 reactor, prompting workers to evacuate before taking a second reading. On Sunday night, however, a TEPCO spokesman said it was an error: "The number is not credible," said Takashi Kurita. "We are very sorry." The radiation levels are being retested. It's still not known where the radioactive water in four of Fukushima's most troubled reactors is coming from, but government spokesman Yukio Edano said some is “almost certainly” seeping from a cracked reactor core in one of the units.