Colorado voters approved a vote Tuesday during midterm elections that would legalize the use of psilocybin and psilocin, two psychedelic compounds found in so-called magic mushrooms, becoming the second state to do so in two years.

The measure passed by a narrow margin, the Associated Press predicted, with 52% of more than 2.2 million votes in favor of legalization, with 93% of scheduled ballots counted through Friday.

The initiative permits the use of psilocybin in state-regulated facilities under the supervision of licensed facilitators. It also legalizes the private personal use, cultivation and exchange of psilocybin and psilocin, as well as three additional narcotics (DMT, ibogaine and mescaline) by adults 21 and older. Retail is not permitted and the law has several restrictions, including restrictions prohibiting use in public, at school or while operating a motor vehicle.

“I’m amazed at what we’ve accomplished,” said Veronica Lightning Horse Perez, a key supporter of the legalization effort. “Over a million people voted yes to this. To think that so many people see the value in these drugs, that so many people know they can be used to heal, is huge.

Psilocybin is federally illegal in most states, although it is not a criminal offense in Washington, DC. and in more than a dozen other cities. But a growing body of research has found anti-anxiety therapeutic uses for the chemical, prompting some states to consider easing restrictions.

Oregon voters passed a measure legalizing magic mushrooms for therapeutic use in 2020, and lawmakers in Washington and New York introduced bills this year to legalize them.

Bills decriminalizing ownership have been introduced in 19 states, including Missouri, Iowa and Kansas, although none have passed. And more than a dozen states, including Florida, Oklahoma and Texas, have introduced legislation to further study the health benefits of psilocybin.

“More and more people are starting to realize and understand that when it comes to psychedelic treatment, it’s not exactly a radical field. It’s becoming more popular,” said Oklahoma State Representative Daniel Bay, co-author of a bill that would allow scientific research on psilocybin.

The bill, which has passed the Oklahoma House of Representatives and will be taken to the Senate for consideration, would allow adults with certain conditions to participate in the state’s psilocybin clinical trials. Texas passed a similar law last year.

The potential for narcotics to be part of treatments for depression, anxiety, post-traumatic stress disorder, drug addiction and eating disorders is being evaluated in several clinical trials. In 2018, the Food and Drug Administration called psilocybin a “breakthrough therapy,” a designation that accelerates the development of drugs that may be more effective than current therapies.

Hawaii’s Senate cited the FDA’s designation in March when it passed a bill that would convene a task force to develop a long-term plan to make psilocybin available to adults age 21 and older seeking mental health treatment. Connecticut lawmakers convened a psilocybin study group last year and adjusted their state budget to fund treatment programs that give psychedelic treatments to veterans and retired first responders.

While more than 60 bills have been introduced across the country, most, including the Hawaii bill, are stalled in committee or have not been voted on. In Washington, lawmakers opted to study the substance after fighting to loosen restrictions. And in California, lawmakers turned a bill to decriminalize use into one that would examine policy.

In Colorado, the winning vote marks the second time in three years that the state has made doping history. Denver became the first US city to decriminalize psilocybin in 2019.

For Kevin Franciotti, an addiction counselor in Denver who received sedative treatment for an opioid use disorder more than a decade ago, this is “Colorado’s opportunity to be a leader in guiding US drug policy.”

Not everyone agrees with the legalization of drugs. Some opponents of the Colorado measure say it would bar the use of va