(TOKYO) -- The threat of radiation exposure was heightened in Japan Tuesday following an explosion and fire at the Fukushima Daiichi nuclear plant which later prompted officials to warn people in a 30-kilometer (19-mile) radius to stay indoors.
"Please do not go outside," said Chief Cabinet Secretary Yukio Edano through a translator. "Please stay indoors. Please close windows and make your homes airtight. Don't turn on ventilators. Please hang your laundry indoors."
"These are figures that potentially affect health. There is no mistake about that," Edano added.
The explosion, which occurred at 6:10 a.m. local time Tuesday came shortly after the International Atomic Energy Agency announced that the reactors at the Fukushima Daiichi plant were shut down.
While the previous explosions at Fukushima Daiichi reactors 1 and 3 were hydrogen blasts caused by a buildup of steam in the reactor units, the new blast at reactor No. 2 has officials very concerned.
This time, the roof did not blow off and it's now believed the trapped pressure cracked the containment vessel around the reactor's core, allowing radioactive material to seep out.
"It is likely that the level of radiation increased sharply due to a fire at Unit 4," Edano said. "Now we are talking about levels that can damage human health. These are readings taken near the area where we believe the releases are happening. Far away, the levels should be lower."
Edano said that "there could be a high level of concentration among the debris from the explosion," and nearly 800 workers were told to leave the plant as a result. For the workers who remain, Edano advised them that they "have to be very cautious when working."
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