Japan's stricken Fukushima Dai-ichi nuclear plant Monday, sending a massive column of smoke into the air and wounding 6 workers. The plant's operator said radiation levels at the reactor were still within legal limits.
Tokyo Electric Power Co. said radiation levels at Unit 3 were 10.65 microsieverts, significantly under the 500 microsieverts at which a nuclear operator must file a report to the government.
The blast follows a similar explosion Saturday that took place at the plant's Unit 1, which injured four workers and caused mass-evacuations.
Japan's nuclear safety agency said 6 workers were injured in Monday's explosion but it was not immediately clear how, or whether they were exposed to radiation. They were all conscious, said the agency's Ryohei Shomi.
180,000 people have evacuated the area in recent days, and up to 160 may have been exposed to radiation.
Earlier Monday, pressure had jumped inside Unit 3, forcing the evacuation of 21 workers. But they returned to work after levels appeared to ease.
Associated Press journalists felt the explosion in the tsunami-devastated port town of Soma, some 25 miles (40 kilometers) north of the reactor. They reported feeling the faint rumble of a blast and the ground shaking.
Four nuclear plants in northeastern Japan have reported damage, but the danger was greatest at Fukushima's Dai-ichi plant. Operators have lost the ability to cool three reactors at Dai-ichi and three more at another nearby complex using usual procedures, after the quake knocked out power and the tsunami swamped backup generators.
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