AUGUSTA — A bill to decriminalize possession of small amounts of psychedelic mushrooms came close to passing in the Maine Legislature, but was ultimately rejected by lawmakers.

After initially approving the bill by narrow margins of one vote each in both the House of Representatives and Senate, lawmakers reversed course. The House voted 74-72 Monday against the bill. The Senate deadlocked Tuesday in a 16-16 vote, effectively killing the legislation.

The bill would have decriminalized the possession of one ounce or less of psilocybin, the psychedelic compound found in certain species of mushrooms, for adults age 21 and older. Psilocybin is currently a Schedule X drug in Maine, possession of which is a Class D crime.

The bill’s near passage came after a push from military veterans and others who say psilocybin is an effective way of treating anxiety and depression. And the close votes represented progress for a group that has been advocating for therapeutic use of psilocybin for at least three years.

Still, the bill, LD 1034, had an uphill climb. The Maine Department of Public Safety testified against the proposal this spring, while the Maine Center for Disease Control and Prevention testified neither for nor against.

Gov. Janet Mills, a former Democratic prosecutor, did not weigh in on the bill.

The bill’s sponsor, Rep. Grayson Lookner, D-Portland, urged fellow lawmakers to support it during a floor debate last week.

“This is a matter of compassion, common sense and justice,” Lookner said. “We have before us an opportunity to alleviate profound suffering, particularly among our veterans who have borne the invisible wounds of war.”

Lawmakers on the Criminal Justice and Public Safety Committee heard from several veterans who spoke in support of the bill during a public hearing in March, including Cecilia Corey, a Hartland resident who said she experienced sexual trauma in the Air Force and also lost her son in a murder-suicide.

“(Psilocybin) was immensely helpful,” Corey said. “It took my extreme symptoms of PTSD from feeling like I was drowning in them to a completely manageable level. I’ve become a better parent, a better partner to my husband, and I’ve experienced relief from my depression, anxiety and PTSD symptoms.”

Oregon and Colorado, as well as Washington, D.C., Detroit and Seattle and other U.S. cities, have decriminalized psilocybin in recent years.

Maine has considered doing so in the past, although bills that proposed making psilocybin available to adults through state-regulated treatment centers failed to pass in each of the last two legislatures.

Scott Pelletier, commander of the Maine Drug Enforcement Agency within the Department of Public Safety, told lawmakers at the March public hearing that while medical studies and research have shown benefits of psilocybin therapy in conjunction with psychotherapy, such studies have taken place in controlled environments. He expressed concerns about quality control outside of lab settings.

“This bill has the word therapeutic in the title, but the source of the 1 ounce amount is unknown and the lack of any connection to psychotherapy or the quality control of psilocybin is troubling,” Pelletier said in written testimony.

Dr. Puthiery Va, director of the Maine CDC, urged lawmakers to proceed cautiously with the proposal. She said psilocybin, under the right conditions, has offered a promising treatment of certain mental health conditions. But the effects can be unpredictable and vary from person to person.

“By allowing possession of a limited amount of psilocybin, Maine will be assuming a ‘therapeutic amount’ with no therapeutic framework and will become one of the few states in the U.S. to deprioritize or decriminalize psilocybin ahead of changes at the federal level,” Va told lawmakers in March.

Staff Writer Randy Billings contributed to this story.