Officials said this is the first time that unaccounted-for smallpox has been discovered.
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Government workers cleaning out an old storage room at a research center near Washington made a startling discovery last week – decades-old vials of smallpox packed away and forgotten in a cardboard box.

The six glass vials of freeze-dried virus were intact and sealed with melted glass, and the virus may well have been dead, because it wasn’t kept cold over the years, officials at the Centers for Disease Control and Prevention said Tuesday.

Still, the find was disturbing because for decades after smallpox was declared eradicated in the 1980s, world health authorities believed the only samples left were safely stored in super-secure laboratories in Atlanta and in Russia.