After potentially serious back-to-back laboratory accidents, federal health officials announced Friday that they had temporarily closed the flu and anthrax laboratories at the Centers for Disease Control and Prevention in Atlanta and halted shipments of all infectious agents from the agency’s highest-security labs.

The accidents, and the C.D.C.’s emphatic response to them, could have important consequences for the many laboratories that store high-risk agents and the few that, even more controversially, specialize in making them more dangerous for research purposes.

If the C.D.C. — which the agency’s director, Dr. Thomas Frieden, called “the reference laboratory to the world” — had multiple accidents that could, in theory, have killed both staff members and people outside, there will undoubtedly be calls for stricter controls on other university, military and private laboratories.

In one episode last month, at least 62 C.D.C. employees may have been exposed to live anthrax bacteria after potentially infectious samples were sent to laboratories unequipped to handle them. Employees not wearing protective gear worked with bacteria that were supposed to have been killed but may not have been. All were offered a vaccine and antibiotics, and the agency said it believed no one was in danger.