Scientists found vials of smallpox virus in a storeroom of a National Institutes of Health facility in Bethesda, Maryland.

From the CDC statement:

The laboratory was among those transferred from NIH to FDA in 1972, along with the responsibility for regulating biologic products. The FDA has operated laboratories located on the NIH campus since that time. Scientists discovered the vials while preparing for the laboratory's move to the FDA's main campus.

The vials appear to date from the 1950s. Upon discovery, the vials were immediately secured in a CDC-registered select agent containment laboratory in Bethesda.

There is no evidence that any of the vials labeled variola has been breached, and onsite biosafety personnel have not identified any infectious exposure risk to lab workers or the public.

(Variola is another term for smallpox.)

Currently under international agreement samples of smallpox are only supposed to be kept in one of two labs in the world - the U.S. Centers for Disease Control and Prevention in Atlanta and the VECTOR Institute in Novosibirsk, Russia.