Workers at Greenleaf Compassionate Care Center, in Portsmouth, one of Rhode Island’s three existing medical marijuana dispensaries, voted to unionize Monday. 

By a vote of 21-1, the workers joined Local 328 of the United Food and Commercial Workers, a union which represents more than 11,000 workers in Rhode Island in fields ranging from the retail food industry, to healthcare, to manufacturing and cosmetology. 

Sam Marvin, the union’s director of organizing, said 28 workers were eligible to vote. While the numbers are small, it is the first time, he said, that workers at a Rhode Island dispensary have unionized. (Workers at a Warwick marijuana cultivation company organized in October.) 

More:Medical-pot sales in R.I. set new annual record: Almost $60 million

More:Application window for medical marijuana dispensary licenses set to close

More:Fired marijuana dispensary official sues company

And with Rhode Island expected to expand the number of medical marijuana dispensaries to nine this year – and two legislative proposals being discussed now to legalize recreational use of the drug — Marvin said he hoped the vote served as momentum for other cannabis workers to unionize.