The struggle to contain radiation at the Fukushima Dai-ichi complex has unfolded with near-constant missteps - the latest involving three workers drenched with water feared to be contaminated.
Safety officials said Wednesday that the three were fine and did not register high radiation levels, but the incident fed criticism of the utility that owns the plant as well as scrutiny of Japan's preparedness for nuclear crises.
The March 11 tsunami that slammed into Japan's northeast, wiping out towns and killing thousands of people, knocked out power and backup systems at the coastal nuclear power plant.
More than 11,000 bodies have been recovered, but officials say the final death toll is expected to exceed 18,000. Hundreds of thousands of people remain homeless, their homes and livelihoods destroyed. Damage could amount to $310 billion - the most expensive natural disaster on record.
"Our preparedness was not sufficient," Chief Cabinet secretary Yukio Edano told reporters Tuesday. "When the current crisis is over, we must examine the accident closely and thoroughly review" the safety standards.
An Associated Press investigation found that Tokyo Electric Power Co. officials had dismissed scientific evidence and geological history that indicated that a massive earthquake - and subsequent tsunami - was far more likely than they believed.
That left the complex with nowhere near enough protection against the tsunami.
The mission to stabilize the power plant has been fraught with setbacks, as emergency crews have dealt with fires, explosions and radiation scares in the frantic bid to prevent a complete meltdown.
The plant has been leaking radiation that has made its way into vegetables, raw milk and tap water as far away as Tokyo. Residents within 12 miles (20 kilometers) of the plant have been ordered to leave and some nations have banned the imports of food products from the Fukushima region.
Highly toxic plutonium was the latest contaminant found seeping into the soil outside the plant, TEPCO said.
Safety officials said the amounts did not pose a risk to humans, but the finding supports suspicions that dangerously radioactive water is leaking from damaged nuclear fuel rods.
"The situation is very grave," Edano said.
Workers succeeded last week in reconnecting some parts of the plant to the power grid. But as they pumped in water to cool the reactors and nuclear fuel, they discovered numerous pools of radioactive water, including in the basements of several buildings and in trenches outside.
The contaminated water has been emitting many times the amount of radiation that the government considers safe for workers. It must be pumped out before electricity can be restored and the regular cooling systems powered up.
That has left officials struggling with two crucial but contradictory efforts: pumping in water to keep the fuel rods cool and pumping out contaminated water.
Officials are hoping tanks at the complex will be able to hold the water, or that new tanks can be trucked in. On Tuesday, officials from the Nuclear Safety Commission said other possibilities include digging a storage pit for the contaminated water, recycling it back into the reactors or even pumping it to an offshore tanker.
The latest accident occurred Tuesday when three workers trying to connect a pump outside the Unit 3 reactor were splashed by water that gushed from a pipe. Though they wore suits meant to be waterproof and protect against high levels of radiation, nuclear safety official Hidehiko Nishiyama said the men were soaked to their underwear.
They quickly washed it off and were not injured, officials said.
"We checked the level of radiation on their bodies and found no radiation," Yoshiyuki Tada, a NISA spokesman, said Wednesday. "The workers are fine and they don't need to go to hospital."
Last week, two workers were hospitalized with burns after they waded into highly radioactive water that reached their knees while wearing ankle-high protective boots. They have been treated and released.
Nikkei, Japan's top business newspaper, called it "outrageous" that TEPCO had been slow to release information about trenches outside the reactors filled with contaminated water, one just 2 inches (5 centimeters) from overflowing.
On Monday, Edano blasted TEPCO for a major miscalculation that saw company officials announce a wildly high radiation level at the plant over the weekend that turned out to be an error.
"This sort of mistake is not something that can be forgiven," he said.
TEPCO's shares plunged nearly 20 percent on Tuesday alone. Its share price has nose-dived a staggering 73 percent since the tsunami.
Prime Minister Naoto Kan reiterated in a speech to parliament that Japan was grappling with its worst problems since World War II.
"This quake, tsunami and the nuclear accident are the biggest crises for Japan" in decades, Kan said Tuesday, dressed in one of the blue work jackets that have become ubiquitous among bureaucrats since the tsunami. He said the crises remained unpredictable, but added: "We will continue to handle it in a state of maximum alert."
Kan has faced increasing criticism from opposition lawmakers over the handling of a nuclear disaster stretching into a third week.
"We cannot let you handle the crisis," lawmaker Yosuke Isozaki said in parliament. "We cannot let you be in charge of Japan's crisis management."
Associated Press writer Shino Yuasa in Tokyo contributed to this report.