Concrete with high radiation levels was likely used for the foundation of an apartment building in Fukushima Prefecture, forcing the builder to find new homes for some of the tenants, which include many evacuees from the nuclear accident.
Concrete with high radiation levels was likely used for the foundation of an apartment building in Fukushima Prefecture, forcing the builder to find new homes for some of the tenants, which include many evacuees from the nuclear accident.
Concrete from the same supplier is suspected of being used at hundreds of construction sites, the city and central government announced on Jan. 15.
“We cannot move immediately,” said a 63-year-old woman who lives on the second floor of the apartment building in Nihonmatsu with her husband and two grandchildren. “I wonder whether radioactive materials can be removed.”
High radiation levels apparently come from crushed stone processed at a quarry in what is now a planned evacuation zone near the Fukushima No. 1 nuclear power plant, which was crippled by the March 11 Great East Japan Earthquake and tsunami.
The quarry operator said there is a low possibility that crushed stone or concrete went out of the prefecture.
The three-story apartment building was completed in July. The woman moved in from Namie, Fukushima Prefecture, due to the nuclear accident.
Many others have also evacuated to the apartment building due to the accident.
At a news conference on Jan. 16, Chief Cabinet Secretary Osamu Fujimura said the government will investigate other quarries in the planned evacuation zone.
However, he said annual radiation levels at the apartment building are below 20 millisieverts, standards used for issuing evacuation instructions.
It is estimated that a person will be exposed to about 10 millisieverts over a year if he or she stays in a ground-floor unit for 24 hours a day.
Radiation levels of 1.16 to 1.24 microsieverts per hour were detected at a height of 1 meter in a ground-floor unit, more than 0.7 to 1 microsievert outside the building.
In second- and third-floor units, radiation levels ranged between 0.10 and 0.38 microsievert.
At the quarry in Namie, crushed stone was stored under simple roofing and shipped until the area was designated as part of the planned evacuation zone with high radiation levels on April 22.
The quarry operator, Futaba Saiseki Kogyo, shipped 5,200 tons of crushed stone to 19 companies in the prefecture between March 14 and April 22, President Mitsuru Igari said Jan. 16.
He apologized for inconveniencing apartment tenants, but said he had no idea the material had been contaminated with radiation.
Igari believes that most of the stone was used for road and other civil construction projects, while it sold about 1,000 tons each to two concrete companies.
A company that supplied concrete to the builder of the apartments sold concrete to more than 100 companies in the prefecture, according to the industry ministry and other sources.
The city government measured accumulated radiation levels in children and other residents between September and November.
It investigated the apartment building after a relatively high radiation level of 1.62 millisieverts was recorded in a junior high school student who lives in an apartment over a three-month period.
A 41-year-old woman who also lives on the second floor of the building said the companies involved should have paid attention to crushed stone processed in an area that was designated as part of the planned evacuation zone.
“High radiation levels in the planned evacuation zone attracted so much attention,” said the woman, who came from Namie with her three children, all junior and senior high school students. “I wonder if they didn’t give any thought to it.”
The concrete supplier and the builder of the apartments also said they did not know the stone was contaminated with radioactive materials.
“We knew that stone came from a quarry in Namie, but we never dreamed that it had high radiation levels,” said an executive of the construction company.
There are no standards on radiation levels for stone and gravel while cement, a key material of concrete, has such standards.
The central government set standards for cement in June after high concentrations of cesium were detected from sewage sludge, a material used in mixing cement.