COLUMBUS (AP) — Those on both sides of a marijuana legalization proposal in Ohio were looking ahead to the fall election on Monday, with supporters announcing a statewide tour and opponents formally launching their campaign to defeat the issue.

Passage of the proposed amendment on Nov. 3 would make Ohio a rare state to go from entirely outlawing marijuana to allowing it for all uses in a single vote.

Under the proposal, adults 21 and older could purchase marijuana for medicinal or recreational use and grow four plants for personal use. It creates a network of 10 authorized growing locations around the state, some that have already attracted private investors, and lays out a regulatory and taxation scheme for cannabis.

The group ResponsibleOhio, which brought the issue to the ballot, said Monday it will promote its plan statewide from a bright green, camper-like vehicle adorned with marijuana leaves and phrases such as “YES on legalization.” Backers will travel to all 88 counties ahead of Election Day, stopping at college campuses, local landmarks and town squares to tell voters “the high points of why marijuana reform is so needed in our state,” said Faith Oltman, a ResponsibleOhio spokeswoman.

The tour announcement came hours before critics of the proposal gathered at Nationwide Children’s Hospital in Columbus to announce their opposition campaign.

The so-called Ohioans Against Marijuana Monopolies includes business groups, hospitals, medical providers, the Ohio Farm Bureau Federation and others. State lawmakers, faith leaders, former state Attorney General Betty Montgomery and former Ohio House Speaker Jo Ann Davidson also joined the coalition for its announcement.

Among other concerns, opponents say the proposal would put children’s health at risk because it would increase their access to edible-pot products, such as candies, cookies and brownies.

Reggie Fields, a spokesman for the Ohio State Medical Association, said the organization could not see “any healthy lifestyle benefit from the recreational use of marijuana.”

Backers of the issue claim those who sell or provide pot to those under age 21 would be penalized and edible-pot items must meet childproof packaging requirements.

“Right now in the state of Ohio, drug dealers are selling to kids without IDing them,” Oltman told reporters.

ResponsibleOhio claims it’s prepared to spend $20 million on the ballot issue.

Opponents said they plan to begin soliciting campaign contributions and will rely on coalition members to spread the word.

A separate fall ballot issue takes aim at the growing sites described in the proposed amendment.

Voters will be asked whether monopolies and cartels should be banned from being added to Ohio’s constitution. Officials say the anti-monopoly measure is written in a way to trump the marijuana amendment.

On Tuesday, the state Ballot Board is slated to approve the phrasing that voters will see on Election Day for all ballot issues.