I put the word radioactive in parenthesis in the title because I'm not fully convinced that the crushed stones from the stone pit in the planned evacuation zone in Namie-machi are the only cause of the elevated radiation in the apartment in Nihonmatsu City in Fukushima.
Nevertheless, the latest news on the "radioactive" crushed stones is:
The stones were sold and widely used in construction of apartments, houses, and roads in at least 4 municipalities including Fukushima City in Fukushima Prefecture;
The Nihonmatsu city government knew about the high radiation exposure of the residents in the apartment back in December but didn't tell the residents.
The Ministry of Economy, Trade and Industry knew about it on December 28, 2011 when the city emailed the Ministry asking for guidance, but didn't do anything until January 10, 2012 because it was New Year's Day holiday and then a long weekend on January 7, 8 and 9.
The residents in the apartment weren't informed at all, until the news finally broke in the media.
Oh and one typically Japanese bit of information: the concrete company in Nihonmatsu City who delivered the concrete with these crushed stones in it for the apartment foundation has since closed business, and they already destroyed all the documents detailing how much concrete was sold to which job site. Probably only to emerge as a new company under a new name, as often happens in Japan.
Many residents of the apartment are evacuees from Minami Soma City and Namie-machi, having escaped the radiation from the Fukushima I Nuclear Plant accident, only to receive added extra by settling in Nihonmatsu City in this apartment.
First from Sankei Shinbun archived at a message board, as Sankei's news links may not last long (1/17/2012):
Concerning the detection of radiation inside an apartment in Nihonmatsu City in Fukushima Prefecture that was higher than outside, the same concrete mix was also used in the construction of single-family houses, according to the concrete company. Relatively high level of radiation has also been detected at an irrigation channel. It has also been revealed that the Ministry of Economy, Trade and Industry had received the first report at the end of last year.
According to the stone pit operator Futaba Saiseki Kogyo, the company shipped about 5,280 tonnes of stones from March 11 to April 22 last year to 19 companies in Fukushima Prefecture. The radiation levels of 1.62 to 1.97 microsievert/hour have been detected at the concrete foundation of the apartment and at an irrigation channel in Nihonmatsu City.
According to the concrete company, the same concrete mix was used for foundations of single family houses around Nihonmatsu City. The other concrete company also delivered the concrete mix to build single family houses in Fukushima Prefecture. The crushed stones were also used [as substrate] for the road next to an elementary school in Nihonmatsu City.
According to the Ministry of Economy, the Ministry received an email from Nihonmatsu City regarding the high radiation exposure level of a resident who lived on the first floor of the apartment [a girl wearing the glass badge]. Since the radiation levels were not high on the 2nd floor, the Ministry didn't think it was the concrete that was the problem.
[Wait a minute... If the 1st floor had high radiation and the 2nd floor didn't, wouldn't it be logical to conclude the radiation could be coming from the floor and below?]
Around January 5, 2012, the city's investigation identified the crushed stones as a possible culprit, and the city contacted the Ministry again on January 6. The Ministry started its investigation on January 10, after the long weekend.
In the newly built apartment where the high levels of radiation have been detected, the residents on the 1st floor have started to look for a new place to live. Some of the residents in the apartment are families from Namie-machi and Minami Soma City; part of Namie and Minami Soma is inside the no-entry zone. "We've just had enough." "Complete surprise." They are confused and angry.
According to the rental management company, there are 12 families living in the apartment. Hiroko Yamazaki, 63-year-old housewife, evacuated from Namie-machi with two granddaughters, 9th grader and 5th grader. She has made them wear masks when they go outside.
Yamazaki cannot hide her agitation, and says, "I wish they told us when they found out the radiation level was high. I'm worried for the health of my granddaughters."
A 33-year-old office worker who has evacuated also from Namie-machi with his family says, "For all that trouble to evacuate, we still have to suffer radiation. We've had enough."
The management company says one family on the 1st floor with small children has decided to move out. The company will cooperate with Nihonmatsu City to find the substitute housing, and the family hopes to move in a few days.
There are others who want to move out, but it may be hard to find the substitute housing. Nihonmatsu City has a large number of evacuees fleeing the Fukushima I Nuke Plant accident, and there is hardly any vacancy in rental housing.
Fukushima Minpo (1/17/2012) reports that the stone pit operator Futaba Saiseki Kogyo sold to 2 concrete companies, one in Nihonmatsu who's gone out of business, and one in Motomiya City. They sold concrete mix to 300 companies at over 400 job sites. The stone pit operator also sold to 17 construction companies. The concrete was sold at least in Nimonmatsu City, Motomiya City, Fukushima City, and Ootama-mura.
Hiroki Otani, associate professor at Tokyo Metropolitan University who became famous (or infamous, depending on how you view radiation exposure) last year for declaring "it's safe" on TV for just about every single discovery of radiation contamination, says "1 microsievert/hour radiation will not immediately affect health, so no need to worry. But they'd better not live on a yearly basis", meaning there may be health effect if they continue to live there for more than one year. That's good to know that he now qualifies his remark after 11 months.
Well, unfortunately, these people moved from Minami Soma or Namie with the plume from the broken nuclear power plant, first in a northwest direction via Iitate-mura (of all places) and then south. And they stayed in Nihonmatsu City where the IAEA back in March 2011 was measuring 4.2 microsieverts/hour radiation (link in Japanese).
It's just too bad that Professor Hayakawa's map didn't reach any of these people when it may have mattered.