Denver voters will decide whether psychedelic mushrooms should be decriminalized Tuesday. The unprecedented vote comes after the Denver Psilocybin Mushroom Decriminalization Initiative gathered enough signatures for the question to be added to the election ballot.

The group needed 4,726 signatures — of the more than 8,000 submitted, 5,559 were valid, CBS Denver reported. The issue was then added to the May 7 vote. If it passes, Denver would become the first city in the U.S. to decriminalize the psychedelic drug some call "magic mushrooms."

If the initiative passes, the use and possession of psilocybin mushrooms by adults 21 and older would be at the lowest law enforcement priority in Denver. This would prevent the city from using resources to impose penalties. The drug cannot be sold — but can be grown by users.

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Opponents are ready to fight the ballot measure. Jeff Hunt, Vice President of Public Policy at Colorado Christian University and Director the Centennial Institute, called it a "serious problem," and said "Denver is quickly becoming the illicit drug capital of the world," CBS Denver reported.

The Denver Elections division announced in February that the Denver Psilocybin Mushroom Decriminalization Initiative submitted enough signatures for the question to be added to the Municipal Election ballot on May 7. CBS Denver

"When you look at all the things that we're dealing with, you have high-potency pot, you have proposals for supervised needle infection sights," Hunt said. "The psychedelic mushroom folks are following the same playbook that marijuana did. They're starting with decriminalization and then they're going to move on to commercialization."

However, those who already use mushrooms for medical reasons are ready for the drug to be decriminalized. "I don't think that people should be criminalized or looked upon differently because they are required to take something that can make them feel this much better," one 54-year-old patient currently using psilocybin mushrooms told CBS Denver. The ballot does not differentiate between the medical and recreational use of mushrooms.