Across much of Fukushima’s rolling green countryside they descend on homes like antibodies around a virus, men wielding low-tech tools against a very modern enemy: radiation. Power hoses, shovels and mechanical diggers are used to scour toxins that rained down from the sky 30 months ago. The job is exhausting, expensive and, say some, doomed to failure.

Today, a sweating four-man crew wearing surgical masks and boiler suits clean the home of Hiroshi Saito (71) and his wife Terue (68). Their aim is to bring average radiation at this home down to 1.5 microsieverts an hour, still several times what it was before the incident but safe enough, perhaps, for Saito’s seven grandchildren to visit. “My youngest grandchild has never been here,” he says.

For a few days in March 2011, after explosions at the Daiichi nuclear plant roughly 25km (15.5 miles) to the south, rain and snow laced with radiation fell across this area, contaminating thousands of acres of rich farming land and forests.

More than 160,000 people closest to the plant were ordered to evacuate. The Saitos’ home fell a few kilometres outside the 20km compulsory evacuation zone but, like thousands of others, they left voluntarily.



Invisible poison

When they returned two weeks later their two-storey country house appeared undamaged, but it was covered in an invisible poison only detectable with beeping Geiger counters.

Nobody knows for certain how dangerous the radiation is. Japan’s central government refined its policy in December 2011, defining evacuation zones as “areas where cumulative dose levels might reach 20 millisieverts per year”, the typical worldwide limit for nuclear power plant engineers.

The worst radiation is supposed to be confined to the 20km exclusion zone, but it spread unevenly: less than 5km (three miles) north of the Daiichi plant, our Geiger counter shows less than five millisieverts a year; 40km (25 miles) northwest, in parts of Iitate village, it is well over 120 millisieverts.

Those 160,000 refugees have not returned and are scattered throughout Japan. The nuclear diaspora is swelled by thousands of voluntary refugees. Local governments are spending millions of dollars to persuade them back.

The price tag for cleaning a heavily mountainous and wooded area roughly the same size as Co Wicklow (2,000sq km) has government heads spinning. In August, experts from the National Institute of Advanced Industrial Science and Technology put the total cost of decontamination at $50 billion (€37 billion). The Japan Centre for Economic Research, a Tokyo-based think tank, says the final tally for the Fukushima clean-up will be $600 billion.

The Saitos’ home falls within the boundaries of Minamisoma, a city that has not recovered from the disaster. Most of its 71,000 population fled voluntarily from the Daiichi incident 20km south. A third have yet to return.

“We’ve worked hard to make our city livable again,” says Minamisoma mayor Katsunobu Sakurai. “But everything we’ve done could be for nothing unless the problems at the plant are fixed.”

Fighting radiation is now one of Minamisoma’s few growth industries. The city has set up a permanent office to co-ordinate decontamination with a budget this year alone of $230 million. Since last September, a crew of 650 men has laboured around the local streets and countryside, cleaning schools, homes and farms.

By the end of the year, the operation will employ almost 1,000 people – a large chunk of the town’s remaining able-bodied workforce.



Disputed figures

Radiation levels in most areas of Fukushima have dropped by about 40 per cent since the disaster began, according to government estimates, but those figures are widely disbelieved.

Official monitoring posts almost invariably give lower readings than hand-held Geiger counters, the result of a deliberate strategy of misinformation, say critics. “They remove the ground under the posts, pour some clean sand, lay down concrete, plus a metal plate, and put the monitoring post on top,” says Nobuyoshi Ito, a farmer who opted to stay behind in the heavily contaminated village of Iitate. “The device ends up 1.5m from the ground.”

Critics say toxins wash down from the mountains and forests after the decontamination crews leave, bringing radiation levels back up – though seldom to previous levels.

Local governments are desperate for evacuees to return and must decide on what basis evacuation orders will be lifted. If they unilaterally declare their areas safe, evacuees could be forced to choose between returning home and losing vital monthly compensation from Tokyo Electric Power Co (Tepco), operator of the ruined Daiichi complex.

For the refugees, a worrying precedent has been set in the municipality of Date, which lies outside the most contaminated areas. In December 2012, the local government lifted a “special evacuation” order imposed on 129 households, arguing that radiation doses had fallen below 20 millisieverts per year. Three months later the residents lost the $1,000 a month they were receiving from Tepco.

Still, local leaders say they believe the decontamination will work. “Field tests have demonstrated we can bring levels down to five millisieverts per year and that is our objective,” says Iitate mayor Norio Kanno.

He accepts that some residents might refuse to return until exposure falls further – the limit recommended by the International Commission on Radiological Protection is one millisievert per year. But he insists nobody will be excluded from any relocation plan. “In the end, we need to reach a consensus as a community.”



Toxic waste

The Fukushima clean-up faces another, perhaps insurmountable problem: securing sites to store contaminated soil, leaves and sludge. Many landowners baulk at hosting “interim” dumps – for three years – until the government builds a midterm storage facility.

Local governments across Japan have refused to accept the toxic waste, meaning it will probably stay in Fukushima for good. The waste is stored under blue tarpaulins across much of the prefecture, sometimes close to schools and homes.

At Hitoshi Saito’s home, the decontamination crew have finished a 10-day shift, power-hosing his roof, digging drains and removing 5cm of topsoil from his land. The cleanup has cut radiation by about half, but in the trees a few metres behind his house, the reading is 2.1 microsieverts. “Unless you do something about those trees, all your work is useless,” he berates an official from the city.

The crew may have to return sometime, he speculates. “Whatever happens, we will never have what we had before. It’s clear that my grandchildren will never come here again.”