Maine marijuana growers are increasingly using radiation and other methods to remove contaminants from their products, a process consumers are likely in the dark about.

Despite a state policy requiring remediated products to be labeled as such, Maine’s Office of Cannabis Policy is not enforcing that rule.

In response to a complaint by a dispensary owner in late February, deputy director of operations Vern Malloch acknowledged, “we are not requiring labeling of remediated or treated product,” according to records obtained through a media request.

“We plan to issue guidance on this in the near future,” Malloch wrote.

Office of Cannabis Policy Director John Hudak also told lawmakers last year that the agency hasn’t enforced remediation labeling requirements since at least November 2024.

“The Office began receiving pushback from cannabis cultivators who did not want to label their cannabis if they ‘treated’ their cannabis with radiation or ozone prior to submitting the cannabis for mandatory testing,” Hudak wrote in testimony last year.

A spokesperson for the agency declined to answer specific questions Monday, but confirmed the agency stopped enforcing the rule after some growers raised concerns over the “misleading impact” that labeling treated cannabis has on consumers.

“Requiring label disclosure of the use of irradiation or ozone treatment implies a consumer risk that is not scientifically supported and is potentially misleading in its implication about potential harm from exposure,” Alexis Soucy, OCP’s director of media relations, wrote in an email.

Over the last couple years, several marijuana products have been subjected to recall because of high levels of mold, yeast and other contaminants. Unsafe levels of mold in cannabis can cause flu-like symptoms, including respiratory issues, sinus infections, headaches and dizziness.

But rather than tossing their product, growers can turn to a process called irradiation, often involving gamma rays or X-rays, to remove contaminants.

Supporters say it’s a safe way to reduce waste and prolong shelf lives. Mold and yeast grow naturally just about everywhere and many species are benign. Standard cannabis mold testing does not differentiate between harmful and harmless microbes.

Opponents, however, argue there isn’t enough research about remediating cannabis to say whether it’s safe or not. There is not much data on whether the various types of remediation are effective at killing microbes or are safe for consumers, most of whom don’t know about the practice.

“It’s a complex topic without many answers,” said Yasha Kahn, who co-founded MCR Labs, one of four licensed cannabis testing facilities in Maine. “Hopefully, the rescheduling can lead to more research.”

The federal government moved last week to reclassify cannabis from a Schedule I to Schedule III drug. Decades-long restrictions on cannabis research will be lifted, which acting Attorney General Todd Blanche said will allow for studies into “marijuana’s safety and efficacy.”

Kahn, who operates several testing labs throughout New England, said irradiating cannabis has become increasingly prevalent in legal markets across the country and the world. It’s still debated whether irradiation works as well as it’s supposed to, he said.

‘THIS IS A FAIRLY NEW PROCESS’

There are numerous kinds of cannabis remediation, each with its own pros and cons. Growers most commonly use X-rays, gamma radiation or ozone gas to remove mold and microbes.

Radiation does not kill all the mold, yeast and other microbes present in cannabis outright, Kahn said. Certain species of mold, like harmful mycotoxins, can often survive remediation. Others can remain dormant for months following the procedure.

“Irradiation gets rid of mold’s ability to procreate, and not necessarily permanently,” he said. “You can take that same product and test it again, months from then, and there’s going to be mold growth.”

Some in the industry, like organic marijuana farmer Lizzy Hayes in Mercer, fear that having the option to remediate cannabis removes the incentive to grow clean cannabis. If you can simply use radiation to eliminate mold from harvested crops, she said, why would you put effort into growing mold-free products?

Part of the blame, according to Hayes, lies at the feet of Maine’s recreational cannabis testing regime. Unlike the state’s medical marijuana market, batches of recreational cannabis products must be tested for contaminants like mold, yeast and heavy metals before they can be put on a dispensary shelf.

But since the mold test only detects the presence of mold, not whether it’s harmful, Hayes said many growers save themselves the trouble and irradiate their cannabis by default rather than risking a failed test.

“When you have a regulatory system that incentivizes irradiation, it’s also making it so that customers don’t have access to as high quality of a product,” she said.

Some in the industry disagree. A bill was proposed last year to codify requirements around labeling treated cannabis and inspecting remediation equipment. It was ultimately defeated after many Maine cannabis growers testified in opposition to the bill.

“Radiation and ozone treatment methods are well-established, scientifically validated technologies commonly used in industries far beyond cannabis,” wrote Jacob Racioppi, owner of Goose River Cannabis in Unity. “In fact, they are standard in the food industry.”

Joel Pepin, co-founder of JAR Cannabis Company, owns and operates one of about a dozen X-ray machines in Maine’s cannabis industry. He estimated that about half of Maine’s recreational cannabis has been treated by similar methods. It would be overkill, he said, to require all of that product to be labeled over scientifically unfounded concerns.

“If we apply this same logic to other industries in Maine, then why doesn’t this bill also require dental patients to wear a shirt that says, ‘treated by X-ray’ after leaving the dental office?” Pepin testified.

Neither Racioppi nor Pepin responded to requests for an interview.

Lorri Maling, laboratory director at cannabis testing facility Nelson Analytical, seconded Pepin that remediating cannabis is “more in use now than it was a few years ago.”

While some opponents of irradiation claim the process reduces THC content and eliminates terpenes — the chemicals that give different cannabis strains unique scents and effects — Maling said there’s no data to back that up. Nor is there much data to back up many other conclusions about the effects of irradiating cannabis.

Most of the studies on the effects of irradiation have been on fruits and vegetables, she said, which have not shown any negative effects — though there’s no guarantee that any remediation method will kill all bacteria.

“This is a fairly new process for cannabis,” Maling wrote in an email. “I really cannot say that it is safe or unsafe for cannabis as there really is not enough data on this.”