Radiation around the Fukushima Daiichi plant has reached levels damaging to human health, prime minister reveals Japan is facing the world’s biggest nuclear crisis for decades after radiation around its failing power plant hit levels damaging to human health following a fire and another possible explosion. Fifty technicians are still battling to cool reactors at the Fukushima Daiichi facility but non-essential personnel were ordered to leave. The government had already called in international help in tackling the spiralling crisis. The government ordered any inhabitants remaining in the 12-mile radius exclusion zone to leave immediately, told those between 12 miles and 19 miles away to stay indoors and imposed a 19-mile no-fly zone. Experts backed their assessment that health risks beyond that area were minimal at present. The news was a fresh blow for a region already reeling from the impact of Friday’s magnitude 8.9 earthquake and devastating tsunami. At least 2,400 have been confirmed dead, thousands are missing and millions remain without adequate food, fuel or water. Workers at the Fukushima plant have been battling since Friday to avert a catastrophe after cooling systems failed in the aftermath of the natural disaster. Hundreds of thousands of people have already been evacuated from areas within 12 miles of the facility as a precaution. Readings in parts of the facility hit levels indicating an immediate risk of damage to people without protective gear, the government’s chief spokesman, Yukio Edano, said. The prime minister, Naoto Kan, asked people to remain calm in a televised address but warned: “Radiation has spread from these reactors and the reading of the level seems high … There’s still a very high risk of further radioactive material coming out.” He added that workers were “putting themselves in a very dangerous situation” to try to contain the problems. With confidence diminishing in the Tokyo Electric Power Company’s ability to handle the crisis, Kan had already said he would personally lead a new joint response headquarters. Tokyo has asked both the United Nations nuclear watchdog for expert help and the US nuclear regulatory commission for equipment. Officials have also begun to distribute potassium iodide, which can help inhibit the uptake of radioactive iodide by the thyroid, to evacuation centres. This morning’s leak appears to have been caused by a fire at the number 4 unit, where spent fuel rods were stored. The nuclear safety agency said the blaze was extinguished several hours after it broke out. But the No 2 unit’s containment structure – which prevents radioactive materials from leaking in the event of meltdown – also appears to have been damaged after a possible explosion shortly afterwards. That is of particular concern because the building housing the reactor was damaged by the hydrogen blast at neighbouring unit 3, experts told Kyodo news agency. Edano told reporters that workers were continuing to inject water to cool units 1 to 3. The No 2 reactor was not as stable as the others, but the water injection was working “to a certain level”, he added. Tokyo Electric Power Company, the owners of the plant, admitted for the first time that there was a possibility of partial meltdown, Kyodo reported. Officials have already gauged that as a “high possibility”. Edano told reporters that beyond the 12-mile radius the level should be reduced to one where harm to human health would be minimal or non-existent, although that would depend on wind speed and direction. He said a “minimal amount” of radioactive material might spread to metropolitan areas, but not at harmful levels, adding: “We want you to keep calm. We can continue with our daily lives.” In Tokyo, experts detected slightly higher than normal radiation levels but said they were far below those that would pose a risk to health. Readings at the plant, taken at 10.20am, varied considerably. Edano told reporters that the highest level around one of the reactors was 400 millisieverts, with a reading of 100 millisieverts around another. Professor David Hinde, head of the department of nuclear physics at the Australian National University, said it was the worst nuclear accident since the Chernobyl disaster in 1986 but stressed it was on a far smaller scale. The maximum radiation level was “very, very serious” for workers on site, who would only be able to remain there for the briefest periods. But the risk to those outside the exclusion zone was very small, particularly when seen in the context of their situation as a whole. “Compared to the risk of being on a plain near the sea it’s negligible … No one is looking at the black smoke from the fires and wondering where those carcinogens are going,” he said. An expert told broadcaster NHK that the situation was “very grave”, warning that without protective gear a level of 100 millisieverts could be enough to cause male infertility in a short time. He also said those in the 12-mile to 19-mile zone should dust off their hair and clothes before entering their building, including brushing off the soles of their shoes. Once inside they should close windows and turn off air conditioning. Any laundry hanging out should be left outside. Japan’s central bank pumped billions more dollars into the economy as stocks plunged more than 10% on the back of the news, following a major injection on Monday. Japan Nuclear power Natural disasters and extreme weather Tania Branigan guardian.co.uk