The Rad Source 420 XL uses x-rays to decontaminate cannabis product. This system is about half the size of a compact car. (From Rad Source website)

Being able to zap bad microbes from cannabis seems like a pretty good deal, but the concept of cannabis remediation has mixed reviews among consumers.

The idea of smoking flower that has been dipped in hydrogen peroxide or blasted with gamma radiation might seem like the fodder of awful science fiction, the practice is widespread enough that most casual consumers of legal adult use cannabis have been exposed to it, let alone their medical patient counterparts.

Remediation is essentially the method by which producers prevent their products from failing lab tests for impurities – most often microbials such as a bacteria, mold, or yeast.

Contaminated product can be treated with ozone, chlorine dioxide, or hydrogen peroxide. It can also be irradiated with x-rays or gamma rays. In some instances, contaminated flower can also be remediated through the process of extracting the THC for concentrates.

“It’s a very broad term,” said Mike Kahn, CEO of MCR Labs, which operates in Massachusetts and Maine. “If something is wrong you remediate it and make it better.”

That being the case, Kahn said that it was tough to tell how much of the samples his lab received have been preemptively remediated.

More specifically, Kahn said that it was easier to tell if a sample at his lab had been previously remediated through the use of chemicals, though that method was rare in Massachusetts, compared to other states he has observed.

“If they dip the flower in peroxide or alcohol, you can tell,” he said. “The flowers just don’t look right, and the customer can generally tell.”

In comparison, irradiating flower or using ozone was difficult to determine with the naked eye.

Tess Eidem, a microbiologist who has worked for various cannabis companies as well as a remediation company, argued that the availability of remediation can make it easier for large grow operations to ignore nagging cultivation problems that without pre-emptive remediation, would make it harder to pass lab testing.

“If you fail, you’re done, but there’s kind of loopholes, so before you submit the lot for testing, you can basically remediate it,” she said.

Preemptive remediation can theoretically be an effective method to pass lab tests, but Eidem argued that if the product is already at a point where remediation is needed to help it pass, than damage has already been done.

“It’s already reached some threshold that alters the value or the quality of that product. If you’ve already exceeded that threshold then preemptive remediation is just preventing test failure,” said Eidem.

Ozone treatment and radiation can render microbials inert, but in some cases, the microbial matter remains on the plant. This still leaves a possibility for negative human reactions to the product, especially among medical patients that are immunocompromised.

“So even if they’re dead, if there were a lot of them to begin with, they can still activate your immune system, it can enhance cross sensitivity to cannabis,” she said.

Given the variety of methods available for remediation, different states naturally have different standards for what is allowed.

For example, when Connecticut’s Department of Consumer Protection recently re-examined microbial threshold limits in the state’s cannabis testing requirements, the department noted that it rejected a public suggestion that the state allow producers to remediate cannabis that fails testing.

“The department learned that the reliability and effectiveness of remediation varies widely based on the method used,” said the memo. “Given this variability, and that the request to implement remediation was not substantially reiterated by other commenters, the department is not adopting [public commenter] WI’s suggestion at this time.”

Michigan, on the other hand, allows remediation and just a few months ago regulators openly debated whether or not to require labels that indicate that products have been remediated. Ultimately, the state took no action to make changes.

Massachusetts only allows cultivators and manufacturers to remediate their products twice – once before and after testing. At that point if the product can still not pass testing, the batch must be destroyed.

Maine, allows remediation, with the exception of batches that fail for pesticides or metals. In those cases, the producer retests if they believe their first failure was in error.

Pennsylvania allows cultivators to remediate contaminated flower by processing it into a topical form, but other forms of remediation are not allowed following a failed lab test. This allowance was part of a medical cannabis update that was signed into law June, 2021.

Either way, remediation has a bad reputation among patients – at least among the more vocal patients online.”Buy with your nose,” wrote one user on a Michigan cannabis subreddit. “Remediated weed to me smells slightly musty.”

Note: The original version of this report stated that Pennsylvania allows remediated flower to be processed into a concentrate. That is incorrect, state rules only allow processing into topicals.

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Zack cut his journalistic teeth covering high school sports in the south before spending a decade covering local government, politics and the courts in the Boston, Massachusetts area. He's previously written...