In September 1984 several hundred residents of The Dalles, Oregon, fell ill with salmonella after eating at restaurant salad bars in the town. Seven hundred and fifty one cases were eventually counted and none was fatal. The outbreak was investigated at the time as a natural event, and only a year later, after the collapse of the commune's leadership, was it established that it had been deliberate: members of the Rajneeshpuram commune had cultivated Salmonella Typhimurium and contaminated the restaurants, as a trial run for an attempt to suppress turnout in a county election. It remains the largest bioterrorist attack carried out on American soil.
The commune's second in command, known as Ma Anand Sheela, pleaded guilty in 1986 to charges including attempted murder and the poisoning, served part of a twenty year sentence and was deported. Rajneesh himself was charged with immigration offences, entered a plea that admitted no guilt while accepting conviction, and was required to leave the United States. He returned to Pune, where he had taught before the Oregon period, and died in 1990.
The movement continued, and is not well described by its Oregon years. The Pune ashram operates as a meditation resort, the teaching is published widely, and a large readership encounters it with no connection to any commune. The relationship between that body of teaching and what was done in Oregon is contested among former members themselves, some holding that the crimes were the work of Sheela's faction acting without instruction, and others that the structure of the commune made them possible.