They were all volunteers and the cia set up tables in public to offer random people walking by the trip of their lifetime....
The guys that invented ACID were all playing a game. The game was to secretly dope up someone working in the same building and then to document it all. The challenge was to not be fooled into being doped up. Well one day someone put too much ACID into the coffee pot and someone over dosed and died... yah .. that was the end of that game