Walmart has recalled frozen, raw shrimp sold in 13 states after federal health officials warned of potential radioactive contamination. The U.S.

Some packages of Great Value frozen shrimp sold at Walmart are at risk for potential for Cesium-137 contamination, the FDA says.

The FDA detected Cesium-137, a radioactive isotope, in one shipment of Great Value frozen raw shrimp to Walmart. It said the affected shipment wasn’t sold.