Supervisors unanimously approved an ordinance Tuesday that will prohibit recreational marijuana businesses in unincorporated Marin.

The new ordinance doesn’t mean recreational dispensaries will be banned forever. Rather, it’s an effort to ensure local control over businesses in the recreational marijuana market following the passage of Prop. 64, the Adult Use of Marijuana Act, in November, which about 70 percent of Marin residents voted for. 

The act directs the state to issue licenses for recreational marijuana businesses engaged in cultivation, manufacturing, transportation, testing and storefront sales. It also legalizes the personal possession of up to an ounce of marijuana and the personal cultivation of up to six plants. 

Marin’s new ordinance prohibits outdoor cultivation, but residents can grow up to six plants inside private residences.

“I believe they want local standards [to be] mindful of impacts,” Supervisor Judy Arnold said of those who voted for the act at a first reading of the ordinance last week.

The ordinance stems from three primary concerns. For instance, no state regulations have been released yet, said Tom Lai, assistant director of the Community Development Agency. 

Prop. 64 required the creation of state regulations and a licensing system by Jan. 1, 2018, but some people, including state Sen. Mike McGuire, have expressed skepticism that the state will meet the deadline given the enormity of the task at hand. 

According to the Los Angeles Times, the head of the Bureau of Medical Cannabis Regulation, now also in charge of recreational cannabis, said during a recent legislative committee hearing that the agency will probably be unable to issue normal licenses by Jan. 1, 2018, though perhaps it could issue temporary licenses at that point. It’s the same day that the state is scheduled to start issuing medical marijuana licenses.

Some state lawmakers are also working on legislation to amend the act. A bill has been proposed in the senate to allow marijuana businesses to pay their state taxes and fees at county offices throughout the state, since federal prohibitions make it difficult to use banks and driving all the way to a state agency to pay a bill can be burdensome. Sen. Mike McGuire introduced a bill to make it illegal to market marijuana or marijuana products using the name of a county, or a similar name, if the weed is not actually produced there. 

Without knowing what the state regulations will say, “it’s hard to know how high of a bar we need to reach” to create a local set of rules, Mr. Lai said.

The Adult Use of Marijuana Act differs widely from rules set by the state legislature for medical marijuana in 2015. While both allow local governments to regulate or prohibit those businesses entirely, AUMA may assume that recreational marijuana businesses are permitted unless explicitly banned, and the act does not require applicants for state licenses to receive local approval first. 

The act also designates cannabis as an agricultural crop. In other words, unless specifically banned, Marin’s agricultural lands could potentially be open for cannabis cultivation, leading to concerns over the “displacement of existing agricultural production activities,” according to a county staff report.

A county ban will “ensure no licenses are issued until the county says so,” Mr. Lai said.

Supervisor Damon Connolly said that he wanted medical cannabis to remain separate from recreational cannabis. “They’re serving different populations with different needs,” he said.

Mr. Lai also said the ordinance gives the county time to roll out its medical marijuana dispensary program, which could offer lessons on how to regulate recreational marijuana.

No one spoke at Tuesday’s hearing, but two San Geronimo Valley residents spoke in support of the recreational ban last week at the first reading of the ordinance. Lisa Bell, of Lagunitas, said she did not even consider the agricultural implications of legalizing recreational marijuana until the meeting. “That might cause [an] invasion [of people’s] property,” she worried.

But others spoke against the “vilification” of marijuana, with one person arguing that alcohol and opioids are much more troubling substances. One emergency physician said marijuana was not a gateway drug but rather an “exit” drug that helps people stop using more serious painkillers. Prohibition, she said, “sends a bad message” to those who want to bring it above ground. Another person, Scott Wilmore of San Rafael, said recreational weed could bring millions in tax revenue.

Mr. Lai said that the ban could be lifted in the future, giving staff and supervisors time to mulll over just what should be legal in Marin. What “works up north”—large-scale cultivation—may not work in Marin, he said. But testing, manufacturing and storefront businesses “may be appropriate for some of our neighborhoods.”