The agency charged with regulating Colorado’s first-in-the-nation legal recreational marijuana market potentially put consumers at risk of using contaminated products, a new state audit found.
The report pointed to inconsistent oversight by the Marijuana Enforcement Division and loose state rules around testing marijuana products or contaminants. As a result, it found, nearly 75% of marijuana processed for eventual sale from 2023 through 2025 evaded testing for pesticides.
The audit, released Monday, identified a host of issues, including regulators’ failure to meet regular inspection schedules or to conduct sufficient random checks at dispensaries for contaminated products. It also found that delayed agency warnings to the public allowed potentially contaminated products to remain on shelves for months, sometimes years.
The audit’s conclusions echo several findings of an investigation this year by The Denver Gazette and ProPublica into the Marijuana Enforcement Division’s lapses in policing contaminants entering the legal marketplace.
In one case highlighted by the newsrooms, it took 15 months for a manufacturer to discontinue production of a marijuana sleep aid pill despite consumers warning regulators that the product was harming their livers. The pills had herbal extracts that researchers say can cause liver damage.
Auditors said they did not identify evidence of “widespread health and safety issues” but did find that deficient regulations still left consumers vulnerable.
The audit found that unsafe products had remained on the market for as long as three years before the Marijuana Enforcement Division issued a public warning. The auditor’s review of the agency’s health and safety advisories found that, on average, from 2023 through 2025, contaminated products that were the subject of an advisory remained on shelves for more than seven months. That’s the same number of months the news organizations found contaminated products stayed on shelves before warnings were issued.
The audit also found that it took the agency three and a half months, on average, in 2025 to issue an advisory once it launched an investigation into potential contamination. Even after investigators determined an advisory was needed, it still took the agency a month on average to issue one.
“These issues limit MED’s ability to meet its core objective to identify product safety risks and to help ensure that licensed marijuana businesses meet product safety requirements,” the audit stated. “As a result, there is an increased risk that marijuana products sold in Colorado may have contaminants or that the potency listed on the labels is inaccurate.”
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Colorado allows marijuana businesses to test far less frequently than required by state guidelines if they can show consistent compliance with testing rules. The reduced testing program results “in a significant portion of the marijuana product being sold in Colorado not undergoing testing to ensure it is safe,” the audit stated. Manufacturers also can rely on other testing exemptions, such as for certain marijuana-derived skin and body products, but there is “limited MED oversight” of how manufacturers determine they qualify for an exemption.
Auditors reported that a survey of MED investigators found that more than half said there are or may be widespread marijuana product safety issues in Colorado’s regulated market.
In a statement released Monday night, the Marijuana Enforcement Division emphasized that state auditors found no evidence “to support claims of widespread health and safety issues” with marijuana products for sale in Colorado, but the agency agreed the audit identified areas for improvement. It said that among other things, it would be assessing exemptions to tests currently allowed under state laws and regulations.
The state auditor’s review “allows us to take a critical look at how we can continue to carry out our work, consistent with our commitment to integrity, safety, and continuous operational improvement,” Dominique Mendiola, senior director of the MED, said in a statement.
The auditor’s report highlighted a criticism her agency has repeatedly sidestepped: the absence of independent collection of samples for safety testing. The Denver Gazette and ProPublica found that more than half of states with regulated marijuana markets rely on private labs or an independent third party to collect samples. Colorado marijuana businesses are free to collect their own samples submitted for testing.
The enforcement division’s own investigators told auditors that, as a result, Colorado relies largely on an honor code to ensure the safety of marijuana sold in the state’s dispensaries.
Auditors said that allowing businesses to select their own samples “increases the risk that businesses do not pick samples that are representative of the overall quality of their marijuana product.”
MED regulators at the start of the year said they planned to pursue an overhaul that would have required private lab personnel to collect samples, but they abandoned that effort after manufacturers said it would increase their costs. On Monday, Kyle Lambert, the enforcement division’s deputy senior director, told legislators that the agency opted against an overhaul this year, chiefly because he said it would be a geographic challenge to do away with self-sampling for rural businesses.
“It was decided now wasn’t the right time to propose that as a policy change,” Lambert said, adding that the agency still might revisit the issue.
State Sen. Byron Pelton, a Republican from Sterling, pushed back, saying it was a loophole he thinks the agency should consider closing.
“If I’m a shady character, I know which products I’m going to go sampling and which ones I’m not,” he said. “That’s a pretty gray area to me.”
The audit also questioned the agency’s reliance on businesses voluntarily recalling contaminated marijuana products, saying that “some of these recalls did not succeed at stopping the businesses from selling potentially unsafe product.”
Just last month, The Denver Gazette and ProPublica reported that a Colorado manufacturer voluntarily flagged 49 of its popular marijuana vapes for recall, nearly six weeks after a third-party lab notified the company and regulators that it detected methylene chloride, a chemical the Environmental Protection Agency has sought to ban for most uses because it can cause cancer. The MED issued a health and safety advisory a day after the publications first reported the manufacturer had warned dispensaries to stop selling the vapes, which consumers had been purchasing for over a year.
