The officials say high-levels of contamination was found at a 3-story apartment building in Nihonmatsu City that was completed last July. The city checked the condo for radiation in December after regular monitoring found that children living there had been exposed to higher levels of radiation than other children over a 3-month period.
The city found that the radioactive cesium level on the first floor was 1.24 microsieverts per hour, which is higher than outside. The officials say that the gravel used on the first floor came from a stone-crushing site in Namie Town in a no-entry zone near the crippled plant.
The city and the central government will confirm the cause of the contamination and check if gravel from the same site has been used elsewhere.
Of course, they know contaminated gravel has been used elsewhere, the Japanese Government announced the idea formally in December. The Environment Ministry presented a guideline to reuse radioactively contaminated disaster waste generated in nuclear crisis–hit Fukushima Prefecture as construction materials within the prefecture.
The average density of radioactive cesium in the waste should remain 3,000 becquerels per 1 kilogram at the maximum and it should be covered with a 30–centimeter–thick coating of other materials, such as asphalt, gravel and concrete, to be recycled for purposes including building roads, railways and breakwaters, according to the guideline.