The FDA detected the radioactive isotope in a shipment of imported frozen shrimp that did not enter the U.S. commerce.

Walmart announced a recall on Tuesday for Great Value raw frozen shrimp products after the U.S. Food and Drug Administration detected a radioactive chemical that may pose a safety concern. The FDA detected Cesium-137, a radioactive isotope of Cesium, on a single shipment of frozen shrimp imported from Indonesian company PT. Bahari Makmur Sejati.

The FDA advises consumers not to eat certain shrimp products from Walmart over possible radioactive contamination. What to know about the recall.