The U.S. Food and Drug Administration (FDA) has issued a warning about Walmart’s popular Great Value Raw Frozen Shrimp, which may be contaminated with a radioactive isotope called Cesium-137 (Cs-137).

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

Great Value brand frozen shrimp sold at Walmart stores in Ohio could be contaminated with Cesium-137, warns the FDA.