Medical marijuana dispensaries are beginning to open in Hawaii, but they're not allowed to sell their products.

Instead, the leafy medicinal greens they've harvested are sitting on a shelf unsold because nearly a year after dispensaries were legally allowed to open, the state has not yet certified any labs to run required safety tests.

That means dispensaries such as Aloha Green on Oahu have no income despite payroll, rent and operations expenses that top $100,000 a month.

"For us it's a little frustrating, having so many people on board, but it has to be done," said James H.Q. Lee, CEO of Aloha Green. "I'm more concerned for the patients, because people have been calling: 'We see it online, when are you going to open? We need our medical cannabis.'"

Hawaii was among the first states to legalize medical marijuana 17 years ago, but dispensaries were only legalized in 2015. The state's 17,000 registered patients have been left to grow marijuana plants on their own or buy it on the black market.

The delays have been frustrating to potential customers, executives and employees in the nascent industry.

Since they're paying for the space, Aloha Green decided to open their doors to the public Thursday for education and outreach.

"That's indicative of how creative the licensees are having to be, because they're bleeding money," said Carl Bergquist, executive director of the Drug Policy Forum of Hawaii.

By law, dispensaries were allowed to open in July 2016, but none could open their doors or even begin growing cannabis because the state had not approved software to track the product from seed-to-sale.

"People are hoping for dispensaries to open, but they're just waiting and waiting," said Jari Sugano, whose 8-year-old daughter suffers from a form of severe epilepsy that can be treated with medical cannabis. "In the end, the delays are going to come back on the patient to pay back."

But state officials and lawmakers say they're working as fast as they can to set up an industry from scratch while ensuring patient safety.

"The dates that were in the legislation were unrealistic," said Keith Ridley of the Department of Health. "I think we need to reset our timeframes."

Nationwide, it often takes states a year-and-a-half to two years to open medical marijuana dispensaries after passing a law, said Becky Dansky, legislative analyst for the national Marijuana Policy Project. The fastest state to set up dispensaries was Minnesota, which took about 13 months to open a narrow program; on the other hand, Maryland has no dispensaries open nearly five years after passing a law, she added.

"The idea of having dispensaries open in a year was extremely ambitious," Dansky said of Hawaii.

Hawaii also faces unique challenges as an isolated island state with a small population, which makes opening a testing lab difficult.

"Everything's inflated. Lease areas, getting expensive equipment shipped on-island, finding the space," said Michael Rollins, chief administrative officer of PharmLabs, a lab based on Maui that is awaiting certification from the Department of Health.

Given Hawaii's small population, it's not a certainty that labs will earn enough revenue to cover costs, unlike Seattle, with its large population and laws permitting recreational marijuana, Dansky said. Some states with small populations, such as Rhode Island, do not require lab testing, she said.

Changes in Hawaii's regulations are also complicating the process for labs that are trying to open, Rollins said. For example, labs were originally required to test for 700 different pesticides, but the rule was changed to require testing for about 150 pesticides, he said. "That changes what type of equipment you need," he said.

State officials say they are waiting on documents from the three laboratories that have applied, and are likely to approve at least one lab sometime this summer. But they don't want to rush and risk approving an unsafe product.

Aloha Green had expected labs to open in May, Lee said. The crop can keep for up to one year in a cool, dark environment, but over time it loses potency, said Tai Cheng, chief operating officer of Aloha Green.

"I understand people's frustration, but building an industry up from the bottom up, requiring as much regulation as we have, is going to take time," said Hawaii Rep. Della Au Bellati, who pushed for the dispensary law.