FUKUSHIMA, Japan - They risk explosions, fire and an invisible enemy - radiation that could kill quickly or decades later - as they race to avert disaster inside a dark, overheated nuclear plant.
The 180 emergency workers at Japan's crippled Fukushima Dai-ichi complex are emerging as public heroes in the wake of a disaster spawned by an earthquake and a tsunami.
Dubbed by some as modern-day samurai, the technicians were ordered back to work late Wednesday after a surge of radiation forced them to leave their posts for hours.
"I don't know any other way to say it, but this is like suicide fighters in a war," said Keiichi Nakagawa, associate professor of radiology at the University of Tokyo Hospital.
Small teams of the still-anonymous emergency workers rush in and out for 10 to 15 minutes at a time to pump seawater into the plant's overheated reactors, monitor them and clear debris from explosions. Any longer would make their exposure to radioactivity too great.
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Even at normal times, workers wear coveralls, full-face masks with filters, helmets and double-layer gloves when they enter areas with a possibility of radiation exposure. Some of them carry oxygen tanks so they don't have to inhale any radioactive particles into their lungs.
But the burst of radioactivity Wednesday led the government to order an evacuation of the Dai-ichi complex.
"The workers cannot carry out even minimal work at the plant now," Chief Cabinet Secretary Yukio Edano said of the temporary pullout.
The highest reading among various locations that had to be accessed by the workers hit 600 millisieverts, equal to several years of daily exposure limit, according to statistics released by Tokyo Electric Power Company.
Millisieverts measure exposure to radiation, which can cause cancer and birth defects. Severe exposure can cause burns and radiation sickness - nausea and vomiting and harm to blood cells.
A typical individual might absorb 6 millisieverts a year from natural and man-made sources such as X-rays. Small additional annual exposures of under 100 millisieverts are believed to produce no discernible harm, but more carries health risks.
Tony Irwin, an Australian-based nuclear consultant, said the normal dose for a radiation worker is 20 millisieverts a year, averaged over five years, with a maximum of 50 millisieverts in any one year.
"So they would be trying to rotate people to make sure they're within that limit. Now many countries have an emergency limit of 100 msvs a year," he said. "They'll wear radiation monitors, so they can see exactly what they're getting on a real time basis."
Yet on Wednesday, Japan's Ministry of Health Labor and Welfare raised the maximum legal exposure for nuclear workers to 250 millisieverts from 100 millisieverts. It described the move as "unavoidable due to the circumstances."
"Workers persevere amid fears of 400 millisieverts," read one headline in the nationally circulated Yomiuri newspaper.
The newspaper said one male worker who was opening a valve to let out built-up steam was hospitalized after complaining of nausea and exhaustion after being exposed for 10 minutes of radiation, despite wearing head-to-toe protective gear and a mask.
On StarNet: For an interactive presentation about the crisis in Japan, go to azstarnet.com/multimedia
