The Fukushima Prefectural government says rice from a field in the Oonami district, in Fukushima City, are contaminated with 630 becquerels per kilogram of cesium.
The rice came from one farm. There are 154 farms in the Oonami district in Fukushima City, they will now test all the farms.
Officials claim the contaminated rice is still in the warehouse and none was shipped to market.
Until now most contaminated rice, in Japan, was just under the government limit of 500 becquerels per kilogram of cesium. This is the first time rice was found over the limit, and national government officials are now considering banning the sale of rice which comes from Oonami district.