Before last week, there were two known locations in the world that stored specimens of smallpox, which hasn't infected a human since 1979. One was at the Centers for Disease Control (CDC) in Atlanta and the other in Novosibirsk, Russia. And then on July 1 someone in a Food and Drug Administration facility in Bethesda, Maryland found a few old specimens of the virus—one of the deadliest in the history of civilization—just sittin' around in a storage room. From a CDC press release:
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...
Late on July 7, the vials were transported safely and securely with the assistance of federal and local law enforcement agencies to CDC’s high-containment facility in Atlanta. Overnight PCR testing done by CDC in the BSL-4 lab confirmed the presence of variola virus DNA. Additional testing of the variola samples is under way to determine if the material in the vials is viable (i.e., can grow in tissue culture). This testing could take up to 2 weeks. After completion of this testing, the samples will be destroyed.
The FDA took over operation of the facility in question from the National Institutes of Health—which conducts disease research—in 1972, so that might be where the samples originated. No one is believed to have been exposed to the virus.
Here's a piece in Science about the debate over whether to eradicate the world's remaining stocks of smallpox. Of note: one of the arguments against eradication is that we might need to conduct further research on the virus if a terrorist group or rogue state discovered a previously undocumented supply of it and turned it into a weapon.