GENEVA (AP)  The world’s most comprehensive legalized heroin program became permanent on Sunday with overwhelming approval from Swiss voters, who separately rejected the legalization of marijuana.

The heroin program, started in 1994, is offered in 23 centers across Switzerland. It has helped eliminate scenes of large groups of drug users shooting up openly in parks and is credited with reducing crime and improving the health and daily lives of addicts.

The nearly 1,300 addicts selected for the program visit one of the centers twice a day to receive a carefully measured dose of heroin produced by a government-approved laboratory.

They keep their paraphernalia in cups labeled with their names, and use the equipment and clean needles to inject themselves under the supervision of nurses. They also get counseling from psychiatrists and social workers.