"TOKYO — Japan's nuclear crisis intensified dramatically on Wednesday after the authorities announced that a second reactor unit at the stricken Fukushima Daiichi plant in northeastern Japan may have ruptured and appeared to be releasing radioactive steam.

The break, at the No. 3 reactor unit, worsened the already perilous conditions at the plant, a day after officials said the containment vessel in the No. 2 reactor had also cracked.

Such were the radiation levels above the plant, moreover, that the Japanese military put off a highly unusual plan to dump water from helicopters — a tactic normally employed to combat forest fires — to lower temperatures in a pool containing spent fuel rods that was overheating dangerously."

Hiroko Tabuchi and Keith Bradsher report for the New York Times March 16, 2011. [2]

SEE ALSO:

"Last Defense at Troubled Reactors: 50 Japanese Workers" (New York Times)
[3]
"High Radiation Levels Force Japan To Abort Helicopter Mission At Plant" (Washington Post) [4]

"All Workers Evacuated from Damaged Nuclear Plant" (ENS) [5]

"Workers Briefly Evacuate Stricken Nuclear Plant" (MSNBC) [6]