Many turn a suspicious eye towards the government, whether it be just politics or grand conspiracies that consist of human experimentation. Believe it or not, The United States is not innocent of some serious unethical experimentation on humans, mostly without them knowing. Just ask New York Subway patrons.
In 1966 the U.S. Army released Bacillus Globigii, a harmless bacterium that is commonly found in soil, in the New York Subway tunnels. It was part of a field study titled "A Study of the Vulnerability of Subway Passengers in New York City to Covert Attack with Biological Agents," which seems pretty straight forward to me. The same experiment was also done on the Chicago subway.
The experiment was to study, and prepare for, a biological attack on the subway systems. The vulnerability of the passengers was studied and noted. Something like this would cause a firestorm of anger and protests today, but I suppose the government knew what was best back in the day.
The U.S. Has also experimented on humans with chemicals, radiations, surgeries, torture, and other physiological exploits. Of course, this was all for the greater good and science, safety be damned.