In the era of legal cannabis, regulations are the name of the game, but stringent potency and purity tests across the state are keeping nearly 18 percent of cannabis products from hitting the dispensary shelves, according to state-provided data.

A little more than 1,900 marijuana samples failed tests through Aug. 29. While small numbers of failed products came from pesticide contamination or E. coli, the vast majority were found to have a different amount of THC than what was listed on the label. Some dispensary representatives say the testing policies are holding products to a tight standard and leaving a small margin for error. The products must test within 10 percent of the product’s claimed potency, according to the state’s rules.

For instance, if a product lists its own THC percentage as 20 percent, the actual potency of the cannabis has to be within about 2 percentage points of that figure. Any potency lower or higher means the state Bureau of Cannabis Control will block the product from being sold.

Data provided by the California Bureau of Cannabis Control

As far as cannabis flowers go, that’s not a lot of wiggle room for the fluctuation of the plant’s potency said Hezekiah Allen, executive director of the California Growers Association.

“It can come down to where you put the plants,” Allen said. “Flowers on the top shelf are getting most of the sun, flowers in the bottom, in the shade, are getting half-sun. Naturally, you’re going to see some variation.”

Small margins are also not that big of a deal to buyers, Allen said. Even if a product’s THC content does differ from what’s listed on the label by a few percentage points, consumers are mainly looking for low-, mid-, or high-grade cannabis, not specific numbers, he said.

“We don’t see our customers saying, ‘Why is this so low?’” said Ray Markland, manager of EcoCann Dispensary in Eureka.

Not all labs test cannabis the same way. Procedures have evolved over the course of this year and especially after July 1, when the state upped the ante with regulations and testing requirements.

“One of the things we’re seeing now is labs are being held to a higher standard,” Markland said. “We’re seeing lower percentage points across the board.”

Some forms of cannabis are inherently prone to a less-than-exact THC count. The companies that sell them are now operating at a loss, said Savannah Snow, manager of the Humboldt County Collective.

Multiple distributors in the county have stopped offering “shatter” — a glass-like concentrate popularly “dabbed” or vaporized with an electric vape pen — because the batches are smaller and the testing expensive.

Cannabis beverages are also taking a hit. Sodas infused with cannabinoid oil usually carry doses of about 10 milligrams, an amount so low that testing doesn’t always detect it. And when the state bureau insists the labeling has to match the content, companies have to price accordingly.

“You might have two cans of soda that are 10 mg and six milligrams,” Snow said. “They take the same amount of money to produce, but now the six-milligram container has a lower price because you can’t ask people to pay the same amount for two different labels.”

For cannabis businesses, speed bumps like these are just another hurdle to cross. Growers recounted believing July 1 would be a day of reckoning for legal cannabis, by way of these newfound testing regulations. But two months later, many who have dug their heels into the industry are set for the long haul.

“Everything’s changing and has been for some time,” Markland said. “This is just another ripple in the wave.”