Minnesota health inspectors monitoring the sale of hemp-derived THC edibles recently found more than 1 in 3 retailers they checked were carrying illegal high-dose products.

The Minnesota Department of Health inspected 167 retailers that sell hemp-derived cannabis products from August through November. They found that 39% carried products with illegally high doses of THC, the psychoactive ingredient in cannabis.

Hemp-derived edibles and beverages may contain no more than 5 milligrams of THC per serving and 50 milligrams per package under current law.

"Illegal, high-dose hemp-derived products may contain hundreds of milligrams of THC per serving, and with multiple servings in a package, this can add up to thousands of milligrams of THC — far above the legal limit," the department wrote in a bulletin last week. "These products are produced by a variety of manufacturers and if consumed may lead to adverse health effects, such as becoming unresponsive, seizures or psychotic episodes."

More than 70% of the retailers who were inspected had "deficiencies of one kind or another," such as incorrect labeling or product placement, Health Department spokesman Garry Bowman said.

High-dose edibles have been a persistent problem in Minnesota's THC market. The state's first pick to lead its new Office of Cannabis Management, Erin DuPree, stepped aside after reports revealed she sold illegal high-dose products at her Apple Valley cannabis shop.

Minnesota's hemp-derived cannabis market was not closely monitored until this summer, when the Health Department was given authority to inspect products and businesses to ensure they comply with dosage limits, testing requirements and labeling laws, among other issues.

The Office of Medical Cannabis within the Health Department is overseeing the inspections. The office's assistant director, Chris Elvrum, said he wasn't surprised to see so many retailers carrying high-dose products.

"I think the marketplace, it just hadn't been regulated for a while, to any great degree," Elvrum said.

The sweep of retailers occurred when the department had only one inspector on staff. Now, the Health Department has five inspectors and will hire a sixth in January, Bowman said.

The extra staff will be needed to adequately monitor the roughly 3,000 businesses that have registered with the state to manufacture and/or sell hemp-derived cannabis products in Minnesota. That includes liquor stores, hemp shops and breweries.

Between July and October, the state collected nearly $3.4 million in taxes on cannabis products, according to the Department of Revenue. That equates to about $34 million in sales over four months and puts Minnesota on track to exceed $100 million in hemp-derived THC edible and beverage sales over the course of a year.

Going forward, Elvrum said state health inspectors will focus their enforcement efforts on the types of businesses that most commonly sell noncompliant products.

"So, smoke shops and some hemp shops and a few convenience stores. But a lot of them are smoke shops or tobacco shops that carry a variety and have these high-dose products," Elvrum said. "Right now, there's about 800 of those registered."

State inspectors will eventually get around to checking liquor stores, bars and restaurants that sell hemp-derived THC seltzers, Elvrum said, though the Health Department has generally found the beverages to be more compliant than gummy products.

When inspectors find illegal products, they ask the retailer to destroy them on the spot or box them up and destroy them later, Elvrum said.

"So far, all of the places we've visited have either done it on the spot [or] in a few cases, we would send our inspector back to watch them destroy it," he said.

Retailers selling products with illegally high doses of THC may be fined up to $10,000 per incident, according to the Health Department. Businesses that sell hemp-derived cannabis products must also register with the state and could be hit with a $10,000 fine if they don't.

Elvrum said health inspectors haven't issued a fine yet but could if they return to one of these businesses and find them selling illegal products again.

"We are generally giving them the benefit of the doubt on the first visit," Elvrum said. "Certainly, repeated violations of the same nature are going to end up being considered for a penalty."

Star Tribune staff writer Brooks Johnson contributed to this story.