DENVER (Reuters) - Voters in Denver appeared to have said “no” to a plan to decriminalize possession of psilocybin, the hallucinogenic drug in what is widely known as “magic mushrooms”, partial results showed.

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If passed, the ballot initiative would make Colorado’s capital the first U.S. city to end the imposition of criminal penalties for individuals at least 21 years of age for using or possessing the psychedelic drug.

But by 11:30 p.m. on Tuesday (0130 ET on Wednesday), the vote tally stood at 52.45 percent opposed to decriminalization and 47.55 percent in favor, with around 74 percent of ballots counted, according to the city’s elections division.

If the initiative was approved, psilocybin would still remain illegal under both Colorado and federal law. The U.S. Drug Enforcement Administration classifies the drug as a Schedule 1 substance, meaning the agency has deemed that it has a high potential for abuse with no accepted medical application.

Decriminalize Denver, the group behind the ballot question, said psilocybin has a wide range of medical benefits. It has been shown to reduce depression and anxiety and to help in treating tobacco, alcohol and opioid addictions, and with alleviating symptoms of post traumatic stress disorder (PTSD), according to the organization.

“We are decriminalizing mushrooms in Denver because the cure for trauma is connection, and mushrooms are a key,” the group said on Facebook.

Some opponents worry that if passed, the initiative would increase the city’s image as a haven for drugs, given that Colorado was one of the first states to legalize possession and sale of marijuana for adult recreational use.

Denver District Attorney Beth McCann opposes the initiative. But if the measure were approved, she supported formation of a review panel under the initiative to study the effects of the drug and the impact the ordinance would have on Denver, spokeswoman Carolyn Tyler said.

Mayor Michael Hancock, who is running for re-election, has told the Denver Post that he opposes the mushroom question.

Denver residents first voted to decriminalize marijuana possession in 2004, years before Colorado voters ultimately approved its legalization statewide for recreational purposes, establishing a full regulatory framework to license retail outlets and collect sales taxes on cannabis products.

The psilocybin initiative is one of a handful of questions on Tuesday’s municipal ballot that also includes Hancock’s bid for a third term as mayor, and a measure to rescind an ordinance that restricts homeless people from establishing encampments in public places.