Three and a half years after Tokyo Electric Power Co.’s crippled Fukushima No. 1 nuclear power station spewed massive amounts of radioactive materials into the air and water, decontamination work in Fukushima Prefecture has yet to draw to an end.

The government initially hoped to complete the decontamination by the end of last March, but the process continues to lag far behind, prompting the government to push back the goal by three years to 2017.

Due to the slow progress, huge bags filled with contaminated soil can still be seen piled up at hundreds of temporary storage sites across the prefecture, and many residents are in limbo, unable to make up their minds about whether to return home in the near future or to relocate for good.

How are toxic houses and land decontaminated?

The work mainly consists of scraping off the top layer of soil, removing grass and fallen leaves, and washing roofs and walls with water or wiping them off with cloth.

As of March, the removed soil and grass was being stored at more than 660 temporary storage sites set up by municipal governments in Fukushima and at 53,000 decontaminated spots such as school grounds and people’s front yards, according to the Fukushima Minpo newspaper.

Through the decontamination work, officials aim to reduce areas where the annual radiation exposure amount exceeds 20 millisieverts. As a long-term goal, they hope to reduce the annual dosage to less than 1 millisievert.

The International Commission on Radiological Protection has a radiation exposure limit of 1 millisievert per year under normal situations and says that cumulative exposure of 100 millisieverts increases the chance of death from cancer by 0.5 percent.

Who is in charge of the decontamination?

The central government is responsible for decontaminating heavily contaminated evacuation zones in 11 municipalities where annual radiation levels exceed 20 millisieverts.

As for less contaminated areas in 40 municipalities, where radiation dosages range between 1 and 20 millisieverts a year, the municipalities are taking the lead.

How much work has been completed?

As of July, decontamination was completed in about 70 percent of schools, public facilities and farmland in the areas where municipal governments have responsibility.

But about half of the planned decontamination for residential houses, and about 70 percent for roads and forests had yet to be finished, according to Environment Ministry data.

As for the state-run decontamination in the 11 municipalities, work hasn’t started in the area where annual radiation readings exceed 50 millisieverts.

Why is it taking so long?

The major reason is the lack of temporary storage sites that would be used until the government builds more permanent facilities.

Some residents are opposing the temporary storage of contaminated waste out of fear of radiation and uncertainty over how long the bags of tainted soil will be stored there.

But the central government hopes to speed up the whole process after reaching agreement with Fukushima Gov. Yuhei Sato on Sept. 1 to build temporary storage facilities in Okuma and Futaba in return for ¥301 billion in subsidies.

The government plans to start moving waste to the facilities in January and complete the transportation in three years.

The government is currently mulling the best way to move the contaminated waste. Last Thursday, the Environment Ministry proposed a transportation plan to a panel of experts, including using 10-ton dump trucks on expressways to deliver the soil quickly — and hopefully safely — to sites where it will likely sit for decades awaiting permanent disposal.

Will the government’s plan work?

That remains to be seen. The government still needs to negotiate with more than 2,000 landowners to acquire 16 sq. km of land in Okuma and Futaba to build the storage facilities.

At the temporary storage facilities, soil will be stored in accordance with the amount of contamination, and burnable waste such as leaves and wood will be incinerated to reduce the overall amount of waste.

The total is estimated to reach 22 million cu. meters, equal to filling the Tokyo Dome 18 times.

Within three decades, the waste is supposed to moved to the final disposal sites the government plans to create outside Fukushima. However, the locations of these final sites have yet to be found.

The neighboring prefectures are having their own problems with radiation-tainted waste, as their residents are strongly opposed to storage nearby.

In July, the Environment Ministry designated a plot of state-owned land in Shioya, in Tochigi Prefecture, but the mayor and residents are opposed to the plan, saying it will damage the environment in which they live.

How effective is the cleanup process in highly contaminated areas?

According to experiments conducted by the Environment Ministry between last October and January in the area where annual radiation readings exceed 50 millisieverts, atmospheric radiation levels in houses and farmland declined by 50 to 80 percent after the top layers of soil and grass was removed, and walls and roofs were washed.

But the study also showed the limits of decontamination technology, as it stated that even after a thorough cleaning had been carried out, atmospheric radiation levels in many areas remained above 20 millisieverts per year — the threshold for lifting the government’s evacuation order.

How much will it cost in total and who picks up the bill?

By law, Tepco is responsible for covering the cost of decontamination work.

As of March, the government had asked the company to pay about ¥66 billion for the cleanup work, but until then it had paid only ¥36 billion, according to the Environment Ministry. Tepco reportedly refused to pay much of the remaining bill, citing its deteriorating finances.

The government decided last December to finance the cost of the decontamination by selling Tepco shares held by a state-backed fund. But if the government fails to gain the necessary funds through selling the shares, taxpayers’ money might have to be used to pay for the decontamination work, experts say.

The government estimates that the decontamination will cost about ¥2.5 trillion in total. But according to a calculation by the National Institute of Advanced Industrial Science and Technology, it could be twice as much, reaching a staggering ¥5 trillion.