DENVER (AP) Colorado voters have passed a ballot initiative to decriminalize psychedelic mushrooms for people 21 and older and to create state-regulated healing centers where participants can experience the drug under supervision.

Colorado becomes the second state, after Oregon, to vote to establish a regulated system for substances like psilocybin and psilocin, the hallucinogens found in some mushrooms. The initiative, which would take effect in 2024, also will allow an advisory board to add other plant-based psychedelic drugs to the program in 2026.

Supporters argued that the states current approach to mental health has failed and that naturally occurring psychedelics, which have been used for hundreds of years, can treat depression, PTSD, anxiety, addiction and other conditions. They also said jailing people for the non-violent offense of using naturally occurring substances costs taxpayers money.

Natural Medicine Colorado, the group that promoted the measure, called its passage a truly historic moment.

Colorado voters saw the benefit of regulated access to natural medicines, including psilocybin, so people with PTSD, terminal illness, depression, anxiety and other mental health issues can heal, the group said in a prepared statement.

But critics warned that the Food and Drug Administration has not approved the substances as medicine. They also argued that allowing healing centers to operate, and allowing private personal use of the drugs, would jeopardize public safety and send the wrong message to kids and adults alike that the substances are healthy.

The move comes a decade after Colorado voted to legalize recreational marijuana, after initially allowing its use for medical reasons, which led to a multibillion-dollar industry with hundreds of dispensaries popping up across the state.