SALT LAKE CITY — Medical marijuana backers are moving forward with a 2018 ballot initiative that would seek Utah voters’ approval to enact a broad medical marijuana law.

The Utah Patients Coalition got state approval Thursday to start collecting the 113,143 voter signatures for the ballot initiative.

Coalition members say they’re done waiting for state lawmakers who rejected proposals to pass a broad medical pot law three years in a row and want to take the issue to the voters in in November 2018.

Campaign co-director DJ Schanz told the Deseret News ( the signature-gathering process slated to start next week is no small task. They’ll have to traverse the state to meet minimum voter thresholds in at least 26 of the state’s 29 state senate districts.

Opponents of the proposal will also quickly begin campaigning against it, said Jason Perry, director of the Hinckley Institute of Politics. That could make the effort especially challenging in more sparsely populated counties with little room for error.

If successful, it would be the first initiative to have made it to the ballot since 2004. The deadline is April 15 but they’re aiming to get the signatures done a few months early, before the next legislative session in January.

The coalition wants Utah to join 29 other states that allow marijuana to be dispensed and used as a treatment for those with certain medical conditions.

The group has already taken several steps to win signature-gathering approval from Lt. Governor Spencer Cox. His office performed a review of the initiative’s language to make sure it wasn’t nonsensical or patently unconstitutional. The group also had to hold a series of public hearings around the state.

The proposed initiative would set up state-regulated growing and dispensing of marijuana for use by residents with about a dozen types of conditions, including cancer and post-traumatic stress disorder.

Since the proposal was unveiled in late June, the coalition has made changes to establish a limit on the amount of medical cannabis can be transported and removing a short tax deduction provision.