Q-Fever
Back in the 1950s, the Army Medical Unit, the forerunner to USAMRIID, conducted research on human volunteers to establish the cause of Q-Fever, a severe pneumonia initially discovered in Australian slaughterhouses. The agent was thought to be capable of being used as a biological weapon. To sum up, they were right. But instead of combating it, they weaponized it.
The US created over 5,000 gallons of Q-Fever. Since it was easily disbursed, the Q-fever could linger up to 60 days on certain surfaces, and only one bacillus was enough to infect someone. Fortunately, the cache was destroyed once the United States signed the 1972 Biological Weapons Convention.