The Los Angeles City Clerk Monday gave a group of medical marijuana proponents a green light to gather signatures for a ballot measure intended to allow about 100 pot dispensaries to remain open in the city.

According to an official summary, the ordinance would allow groups of five or fewer to jointly grow and share marijuana. Collectives of six or more would be technically prohibited under the ordinance. But the city would barred from prosecuting a select 100 or so dispensaries which meet certain conditions, including having opened before Sept. 14, 2007, when the city first tried to place a moratorium on new pot shops.

The so-called limited immunity plan is supported by United Food and Commercial Workers Local 770, which represents about 500 workers at 50
dispensaries, among others.

In addition to having opened prior to the September 2007 cutoff, collectives must not have ceased operations for 90 days or more except to relocate or in response to federal prosecution; must have no access from adjacent residential zoned lots; and must pass annual police department background checks.

Qualifying dispensaries would have 300 days to move to locations that are a certain distance from schools, parks and other designated places.

A plan by City Councilman Paul Koretz similar to the proposed ballot initiative is also moving through the city legislative process.

Backers of the proposed ballot measure have until Dec. 7 to gather 41,138 valid signatures to put the measure before voters on the May 21, 2013, general election ballot.

The move comes less than one month after medical marijuana proponents were successful in getting the City Council to repeal a ban on medical marijuana dispensaries.

The City Council in July had approved an ordinance banning all storefront medical marijuana dispensaries but allowing patients and licensed caregivers to grow their own cannabis. The so-called “gentle ban” ordinance also allowed three or fewer parties to collectively grow pot.

The Committee to Protect Patients and Neighborhoods—a coalition of medical marijuana advocates comprising Americans for Safe Access, the Greater Los Angeles Collective Alliance and UFCW Local 770—subsequently gathered the necessary signatures needed to put a referendum of the law on a city election ballot.

The City Council conceded that a referendum was sure to pass, the council voted 11-2 in favor of repealing the law instead of putting it to voters.