The Food and Drug Administration said Tuesday that the public should avoid eating certain frozen shrimp sold at Walmart due to concerns that the seafood may have been contaminated with radioactive material.

Health officials said in a news release that it is investigating reports of Cesium-137 (Cs-137) contamination in shipping containers and frozen shrimp products processed by an Indonesian company, PT. Bahari Makmur Sejati of Indonesia, also known as BMS Food.

Some of the raw frozen shrimp products processed by an Indonesian company are sold at Walmart stores in 13 states, including Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Missouri, Mississippi, Ohio, Oklahoma, Pennsylvania, Texas and West Virginia, according to the FDA.

Among the products includes Walmart’s “great value brand frozen shrimp,” the health agency said.

“If you have recently purchased raw frozen shrimp from Walmart that matches this description, throw it away,” the FDA said. “Do not eat or serve this product.”

Health officials advised people to talk to their health care providers if they think they’ve been exposed to elevated levels of the contaminant.

PT. Bahari Makmur Sejati and Walmart did not immediately return requests for comment.

Cs-137 is the radioactive form of Cesium, “a soft, flexible, silvery-white metal that becomes liquid near room temperature” used for medical devices and gauges, according to the Environmental Protection Agency.

Repeated exposure to low doses of Cs-137 can increase the risk of cancer, “resulting from damage to DNA within living cells of the body,” health officials said in their news release.

The FDA said that the U.S. Customs and Border Protection alerted the health agency to the detection of Cs-137 in shipping containers in Los Angeles, Houston, Miami and Savannah, Georgia. It said that all containers and products that tested positive for Cs-137 were denied entry into the country.

Health officials also cautioned that it did not detect Cs-137 in any product above the current derived intervention levels for Cs-137, of 1200 Bq/kg.

However, the FDA said that “the level detected in the breaded shrimp sample could represent a potential health concern” if it is combined with radiation in the environment or from medical procedures.