A piece of concrete panel was 2.5 micro Sv/h.
It was found at a home center in North Tochigi.
In Japan, radioactive sewage sludge or disposal waste ash are treated as normal garbage when it’s under 8,000 Bq/Kg.
They are re-used to concrete material.
This kind of material is highly likely to have been distributed to all around in Japan.
Our houses will be radioactive, sooner than we have ever thought.