Not marketable: Bags of rice grown in the city of Fukushima and contaminated with radioactive cesium exceeding the government limit are piled up in a local warehouse Thursday. KYODO

It is the first ban on rice shipments since the devastating nuclear crisis was triggered by the March 11 earthquake and tsunami.

Chief Cabinet Secretary Osamu Fujimura said the government instructed Fukushima Gov. Yuhei Sato to impose the ban, while also requesting the prefecture to conduct further tests on rice harvested in Onami.

The high cesium level was detected before the rice from that farm was shipped, he said.

The Fukushima Prefectural Government said Wednesday that the cesium level was 630 becquerels per kilogram. The central government’s provisional limit is 500 becquerels.

Onami is about 80 km from the Fukushima No. 1 nuclear power plant.

Fukushima officials said the prefecture had examined earlier samples of rice from the area and didn’t find cesium above the 500-becquerel threshold.

The contaminated rice was found when a farmer from Onami took unmilled rice to a local agricultural cooperative for inspection on Monday.

A more precise test Tuesday confirmed the high level of cesium.

Rice grown on the farm this year has not been shipped. The prefectural government on Wednesday requested farmers in the district to refrain from shipping their harvests.

After passing the initial tests, a total of 1 ton of rice from 86 farms among the 154 in the Onami district has already been shipped to local rice sellers, according to the prefecture.

To prevent tainted rice from making it to store shelves, Fujimura said, “the government will continue inspections as we had been doing before.”

An official said the agriculture ministry will consider launching more efficient food inspections next year.

Meanwhile, Prime Minister Yoshihiko Noda will continue to keep eating rice harvested in Fukushima Prefecture at his official residence, Fujimura said.

Noda wrote in his official blog post last month that he began eating rice from Fukushima on Oct. 21, a few days after visiting the prefecture and promising the people there he would switch to Fukushima rice at the Prime Minister’s Official Residence.

“I want to help even though it may do little to wipe away harmful rumors” about Fukushima agricultural products caused by the nuclear disaster, the blog entry says.