chemtrail conspiracies which argue that chemicals that aren’t inert are being distributed to make it into the air we breathe and the water we drink in order to alter the behavior of people.

https://www.cbsnews.com/news/us-admits-bio-weapons-tests/

http://www.theguardian.com/politics/2002/apr/21/uk.medicalscience

https://www.washingtonpost.com/archive/politics/1977/03/09/army-conducted-239-secret-open-air-germ-warfare-tests/b17e5ee7-3006-4152-acf3-0ad163e17a22/

http://nationalpost.com/news/canada/u-s-secretly-tested-carcinogen-in-western-canada-during-the-cold-war-researcher-discovers

https://www.smithsonianmag.com/smart-news/1950-us-released-bioweapon-san-francisco-180955819/