Three of the workers battling to save Japan's stricken Fukushima nuclear plant have been taken to hospital with radiation burns.
The men, of the "Fukushima fifty" hailed around the world for their work inside the plant, suffered serious leg injuries while wading through contaminated water to lay power cables to the plant.
Officials said the workers, two in their twenties and one in his thirties, were exposed to irradiated water in the number 3 reactor when it seeped through their protective gear, causing them to be contaminated with a level of radiation almost twice as high as the "safe" limit.
They were diagnosed as having sustained burn injuries at a Fukushima hospital, and will be sent to the National Institute of Radiological
Sciences in Chiba prefecture for further tests.
"This is a very regrettable situation," said chief cabinet secretary Yudio Edano. "They were in a basement area of the number 3 reactor, standing in water that was irradiated," he said.
Japan's nuclear safety agency and the plant operator Tepco said the three workers were exposed to radiation amounting to 170 to 180 millisieverts, lower than the maximum limit of 250 millisieverts set by the health ministry for workers tackling the emergency.
The world today got its first glance of the 50 workers, until now an anonymous group of lower and mid-level managers. Pictures from inside the plant show staff in full protective suits and masks working in debris-strewn control rooms lit only by torchlight. They are also pictured working to reconnect power supplies and trying to make the towers in the plant safe.
Five are believed to have died and 15 are injured while others have said they know the radiation will kill them. At first light today officials were alarmed to see steam pouring from reactors 1, 2, 3, and 4. It was the first time that steam has escaped from the No 1 reactor.
Tokyo residents were hoarding bottled water after reports that radioactive iodine in the tap water was more than twice the level considered safe for infants. Today it was declared safe again but high levels of cancer-causing iodine were found in three neighbouring prefectures.
The death toll from the March 11 earthquake and tsunami disasters has reached 9,700. Up to 16,500 people are missing.