Though it later authorized the dumping of slightly radioactive water, the government said Monday it was growing concerned about the sheer volume of contaminated materials spilling into the Pacific. It is not clear how much water has leaked from the pit so far.
"Even if they say the contamination will be diluted in the ocean, the longer this continues, the more radioactive particles will be released and the greater the impact on the ocean," Edano said. "We are strongly urging TEPCO that they have to take immediate action to deal with this."
The crisis has sparked protests in Japan and raised questions around the world about the safety of nuclear power. The head of the International Atomic Energy Agency told delegates at a nuclear safety conference Monday that the industry cannot afford to ignore these concerns.
"We cannot take a 'business as usual' approach," Yukiya Amano said.
The operator said Monday it is ordering fencing that is typically used to contain oil spills. The screens are not designed to trap radioactivity but might curtail the flow of water and thus reduce the spread of contamination, said TEPCO manager Teruaki Kobayashi. It was not clear when they would arrive.
All of the plant's reactors were designed by General Electric, and the company's CEO met Sunday with TEPCO's chairman. Jeffrey Immelt told reporters Monday that more than 1,000 engineers from GE and its partner Hitachi are helping to analyze the problems at the plant.
Immelt also offered assistance in dealing with the electricity shortage brought on by damage to Dai-ichi and other power plants. Japan is expecting a shortfall of at least 10 million kilowatts come summer.
Gas turbines are on their way from the U.S. with both long- and short-term capabilities, Immelt said.
Associated Press writer Ryan Nakashima in Tokyo contributed to this report.