A widening seafood safety scare has prompted federal officials to expand a nationwide shrimp recall for the second time in a week. Walmart’s popular Great Value brand to the growing list of products pulled from store shelves over concerns about possible radioactive contamination.

The FDA has expanded its recall of frozen shrimp over potential radioactive contamination, now affecting more U.S. states.

Federal officials have announced the recall of more packages of frozen shrimp that may be contaminated with a radioactive isotope. California-based Southwind Foods has voluntarily recalled its frozen shrimp products,