For example, the Soviet research facility at Sverdlovsk conducted anthrax research during the Cold War. They isolated the most potent strain of anthrax culture and then dried it to produce a fine powder for use as an aerosol. In 1979, an accident at the facility released anthrax, killing 100.
The U.S. has had its share of accidents. USA Today noted in August:
More than 1,100 laboratory incidents involving bacteria, viruses and toxins that pose significant or bioterror risks to people and agriculture were reported to federal regulators during 2008 through 2012, government reports obtained by USA TODAY show.
In two other incidents, animals were inadvertently infected with contagious diseases that would have posed significant threats to livestock industries if they had spread. One case involved the infection of two animals with hog cholera, a dangerous virus eradicated from the USA in 1978. In another incident, a cow in a disease-free herd next to a research facility studying the bacteria that cause brucellosis, became infected ....
Read the whole thing but this paragraph I found very interesting...
Researchers are creating some very dangerous bugs. The Frederick News Post - an excellent local newspaper for the community surrounding the U.S. Army Medical Research Institute for Infectious Diseases at Fort Detrick - reported in 2010 that the facility would eventually aerosolize Ebola:
Ludwig said researchers at the facility will likely start out working on vaccines for filoviruses such as Ebola and Marburg, as well as new anthrax vaccines.
The facility will have the capability to produce viruses in aerosolized form that would simulate a potential biological attack on the test animals. Ludwig said aerosol is the means of exposure researchers are most concerned with given its implications to battlefield and homeland defense.