This is a short story, but it is too bizarre not to share: A laboratory in Washington apparently had some vials of smallpox lying around which they totally forgot about. Since the 1950s.
As per the BBC:
Long forgotten vials of smallpox left in a cardboard box have been discovered by a government scientist at a research centre near Washington, officials say.
[snip]
"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, [Maryland]," according to a CDC statement.
[snip]
It is the not the first time vials of smallpox have been unexpectedly discovered. Several were found at the bottom of a freezer in Eastern Europe in the 1990s, according to media reports.
http://www.bbc.com/...
Now, I'm not a biosafety expert by any means, but I think that a laboratory which deals in pathogens should keep a detailed list of what it keeps and where. Also, cleaning the ol' fridge from time to time tends to be a good idea.