Unless something changes, the island’s only other cannabis dispensary will sell all its remaining supplies by September at the latest, and Martha’s Vineyard will run out of pot entirely, affecting more than 230 registered medical users and thousands more recreational ones.

The problem boils down to location. Although Massachusetts voters opted to legalize marijuana more than seven years ago, the state’s Cannabis Control Commission has taken the position that transporting pot across the ocean — whether by boat or plane — risks running afoul of federal laws. That’s despite a counterargument that there are routes to Martha’s Vineyard that remain entirely within state territorial waters.

The conundrum led Rose to file a lawsuit last month against the commission, which now says that finding a solution to the island’s pot problem has become a top priority. Three of the five commissioners visited Martha’s Vineyard on Thursday to hear directly from affected residents.

The tension between conflicting state and federal regulations has played out across the country as states have legalized pot. California law, for example, expressly allows cannabis to be transported to stores on Catalina Island, while Hawaii last year dealt with its own difficulties transporting medical marijuana between islands by amending a law to allow it.

Federal authorities have also been shifting their position. The Justice Department last month moved to reclassify marijuana as a less dangerous drug, though still not a legal one for recreational use.

For several years, sellers on Martha’s Vineyard and the nearby island of Nantucket thought they had a solution. They grew and tested their own pot, eliminating the need to import any from across the water.

But Fine Fettle, a Connecticut-based company that had been the sole commercial grower on Martha’s Vineyard and also runs the island’s other dispensary, told Rose last year that it planned to stop growing pot on Martha’s Vineyard and would close its store when its existing supplies ran out.

Benjamin Zachs, who runs Fine Fettle’s Massachusetts operations, said that when the company opened in Martha’s Vineyard, it knew it was illegal to transport marijuana across federal waterways.

“Candidly, when it started, we thought this was a good thing for business,” Zachs said. “A captured market.”

But over time, pot became cheaper with more varied options on the Massachusetts mainland, while the costs of employing testers on the island rose, making it uneconomic to continue such a niche operation, Zachs said. He added that many people bring their own supplies over on the ferry.

But for people living on the island, taking the ferry to buy pot can be expensive and time-consuming. There’s no dispensary in Woods Hole, where the ferry lands, so they either need to take an Uber from there or bring over a car, and space for vehicles is in hot demand over summer. That leaves medical users such as Sally Rizzo wondering how they will access marijuana. She finds the drug helps relieve her back problems and insomnia.

“The nice thing about getting it at a dispensary is that you can tell them specifically what you’re looking for, and know the milligrams, and know the potency, and what’s in it,” said Rizzo, who submitted an affidavit in support of Rose’s lawsuit.

Rose, 77, has lived on Martha’s Vineyard for more than 20 years and opened his Island Time store three years ago. For now, he’s keeping his core staff of five on the payroll. The dispensary’s green logo looks like a hippyish take on the famous Starbucks emblem, with a relaxed woman smelling a bloom under the words “Stop and smell the flower.” But Rose is anything but relaxed these days.

“I’m on the verge of going out of business,” he said. “While I acknowledge the efforts of the commission to address the issue, I really felt that the only way to get some immediate relief was to file a lawsuit. I was not going to sit on the sidelines. I had to do something.”

Rose was joined in his lawsuit by the Green Lady dispensary on Nantucket, which for now continues to have its own homegrown supply but also faces the same high costs of onsite testing.

In the lawsuit, Rose outlines how he told the commission in November that his business faced an existential crisis because Fine Fettle would no longer be growing pot. In March, he took a chance by buying some pot on the mainland and shipping it across on the ferry.

But the commission ordered Rose to stop selling the product he’d shipped over, putting it into an administrative hold. The commission eventually released the marijuana a few weeks later but told Rose he couldn’t ship over any more. In his suit, Rose complains about the commission’s “arbitrary, unreasonable, and inconsistent policy against transport over state territorial waters.”

Island Time is represented by Vicente, a firm that specializes in cannabis cases. It agreed to delay an emergency injunction against the commission until June 12 after the commission said it would enter into settlement discussions.

“We’re cautiously optimistic that we’ll be able to reach resolution, but if we can’t, we’ll be prepared to make the arguments in court,” said Vicente lawyer Adam Fine.

Until last week, the commission maintained that it wouldn’t comment on pending litigation, other than to say there was no special accommodation to allow pot to be transported from the mainland to the islands. But when commissioners traveled to Martha’s Vineyard, they assured residents they were all on the same page.

“Obviously, this is a super priority for us, because we don’t want to see the collapse of an industry on the islands,” said commissioner Kimberly Roy.

She said nobody could have foreseen that there was going to be such a supply chain issue and they wanted to get it resolved.

“It’s a funny juxtaposition,” she said. “The entire industry is federally illegal. But that’s evolving, too. We are just trying to stay responsive and nimble.”